Math/Physics/Chem
What's the difference between anions that end in -ous and -ic?
-ous endings indicate lesser charge; while -ic endings indicate greater charge
What is the cosine of 0 degrees?
1
What is the sin of 90 degrees?
1
What is the sine of 90 degrees?
1
When glycerol reacts with three different fatty acids, how many stereogenic centers does the product triacylglycerol contain?
1 When glycerol reacts with three different fatty acids, how many stereogenic centers does the product triacylglycerol contain?
What are the 2 main solubility rules?
1. All salts containing ammonium (NH4+) and alkali metal (Group 1) cations are water-soluble. 2. All salts containing nitrate (NO3-) and acetate (CH3COO-) anions are water-soluble.
How do we add multiple vectors
1. Resolve the vectors to be added into their x- and y- components. 2. Add the x-components to get the x-component of the resultant (Rx). Add the y-components to get the y-component of the resultant (Ry). 3. Find the magnitude of the resultant by using the Pythagorean theorem. If Rx and Ry are the components of the resultant then R= √R²x +R²y 4. Find the direction (θ)of the resultant by using the relationship θ= tan-¹ Ry/Rx.
How do we create an IQR?
1. To calculate the position of the 1st quartile (Q1) in a set of data sorted in ascending order, multiply n by 1/4. 2. If this is a whole number, the quartile is the mean of the value at this position and the next highest position. 3. If this is a decimal, round up to the next whole number, and take that as the quartile position. 4. To calculate the position of the third quartile (Q3), multiply the value of n by 3/4. Again, if this is a whole number take the mean of this position and the next. If it is a decimal, round up to the next whole number, and take that as the quartile position.
What is the specific heat of water?
1 cal/g*K aka 4.184 J/g*K
What is the sqrt(2)
1.4
What is the sqrt (3)
1.7
What is the y-intercept of the Lineweaver-Burk plot?
1/ Vmax
What is the cosine of 60 degrees?
1/2
What is the sine of 30 degrees?
1/2
If you have multiple lenses in contact, how do you calculate the focal length?
1/f = (1/f1)+(1/f2)+(1/f3)+....+1/fn *An example of lenses in contact is a corrective contact lens worn directly on the eye
What is the NMR for carboxylic acids?
10.5 to 12 ppm
What is the density of water?
1000 kg/m³ = 1 g/ cm³
What is 1000 mOsm/L in moles per liter?
1000mOsm/L = 1000E-3 mol/L = 1 mol/L
What is Faraday's constant?
10^5 C/ mol e- One faraday (F) is equivalent to the amount of charge contained in one mole of electrons
What is the NMR for alkynes?
2 to 3 ppm
Calculate the normality of the following solutions: 2M Al(OH)3 16M H2SO4
2M Al(OH)3 = 6 (because there are 3 OH-) 16M H2SO4 = 32 (because there are 2 H+)
What is the NMR for Aromatics?
6 to 8.5 ppm
What is the NMR for aromatics?
6 to 8.5 ppm
What is the datum?
A fixed reference point where all measurements will be referenced back to
What is centripetal force?
A force that acts on a body moving in a circular path and is directed toward the center around which the body is moving. As a force, the centripetal force generates centripetal acceleration. Remember from the discussion of Newton's laws that both force and acceleration are vectors and the acceleration is always in the same direction as the net force. Thus, it is this acceleration generated by the centripetal force that keeps an object in its circular pathway. When the centripetal force is no longer action on the object, it will simply exit the circular pathway and assume a path tangential to the circle at that point.
What is weight? How is it calculated?
A vector quantity. It is a measurement of gravitational force on an object: Fg= mg
What is a longitudinal wave?
A wave in which the vibration of the medium is parallel to the direction the wave travels
What is the continuity equation for fluids?
A1v1=A2v2 It tells us that fluids will flow more quickly through narrow passages and more slowly through wider ones. It is a statement of the conservation of mass as applied to fluid dynamics.
Describe antidiuretic hormone
ADH aka vasopressin is a peptide hormone synthesized by the hypothalamus and released by the posterior pituitary in response to high blood osmolarity. It directly alters the permeability of the collecting duct, allowing more water to be reabsorbed by making the cell junctions of the duct leaky. Increased concentration in the interstitium (hypertonic to the filtrate) will then cause the reabsorption of water from the tubule. Note: alcohol and caffeine both inhibit ADH release and lead to frequent excretion of dilute urine.
What's the difference between ADH and aldosterone?
ADH only governs water reabsorption and thus results in a lower blood osmolarity. Aldosterone causes both salt and water reabsorption and does not change blood osmolarity.
Malonyl-CoA is produced from acetyl-CoA through the action of acetyl-CoA carboxylase. The byproducts of this reaction are:
ADP + Pi Since the enzyme is a carboxylase, this implies that it adds a CO2 molecule to acetyl-CoA
What is Newton's second law?
Acceleration results from the sum of the force vectors when that sum is non-zero: Fnet= ma A constant force on a mass produces a constant acceleration.
Which gas will exert a higher pressure under the same, nonideal conditions: methane or chloromethane?
According to the van der Waals equation, if a is increased while b remains negligible, the correction term (n²a)/V² gets larger, and the pressure drops to compensate. Therefore, methane will behave more ideally than chloromethane because a is smaller for methane. The real pressure of methane will thus be higher (closer to ideal).
What is the fundamental unit of newton?
(Kg *m) / s²
What is the formula for percent composition by mass?
(mass of solute/ mass of solution) * 100%
Draw Ethanol
C2H5OH
Draw Propane
CH3CH2CH3 (pro meaning 3 carbons)
Draw Acetone
CH3COCH3
What are case-control studies?
Case-control studies start by identifying the number of subjects with or without a particular outcome and then look backwards to assess how many subjects in each group had exposure to a particular risk factor. For example, a study in which 100 patients with lung cancer and 100 patients without lung cancer are assessed for their smoking history would be an example of a case-control study.
What is the formula for catalytic efficiency?
Catalytic efficiency= Kcat/Km
Describe circular motion
Circular motion occurs when forces cause an object to move in a circular pathway. In uniform circular motion, the instantaneous velocity vector is always tangent to the circular path. What this means is the the object moving in the circular path has a tendency (inertia) to break out of its circular pathway and move in a linear direction along the tangent. It is kept from doing so by a centripetal force, which always points radially inward. Thus, in all circular motion, we can resolve the forces into radial and tangential components. Note: In uniform circular motion, the tangential force is zero because there is no change in the speed of the object.
What are the two equations for magnitude of an electric field?
E= Fe/q or E= kQ/ r² *where E is the electric field magnitude in newtons per coulomb, Fe is the magnitude of the force felt by the test charge q, k is the electrostatic constant, Q is the source charge magnitude, and r is the distance between the charges.
What is the formula for calculating the uniform electric field between capacitor plates?
E= V/d or V/L *note: the direction of the electric field at any point between the plates is from the positive plate toward the negative plate. This should not be surprising, as electric field lines always point in the direction a force would be exerted on a positive charge.
What is the formula for photon energy?
E=hf *where h is Planck's constant (6.626e-34 J*s)
How are the electrodes set up in a galvanic cell?
Each electrode is made of a conductive metal that is bathed in an electrolyte containing its cation and sulfate.
How does enthalpy change in exothermic processes?
It decreases because heat is released
If you see a sparingly soluble salt with the formula MX what is the Ksp?
Ksp= x² (assuming no common ion effect)
If you see a sparingly soluble salt with the formula MX₂ what is the Ksp?
Ksp=4x³ (assuming no common ion effect)
Describe entropy on a macroscopic level and in statistical terms
On a macroscopic level, entropy can be thought of as the tendency towards disorder. Statistically, entropy is the measure of the spontaneous dispersal of energy at a specific temperature, increasing the number of available microstates for a given molecule (increased microstates= distribution of potential energy over larger number of microstates= increased entropy).
Order of polarity of functional groups
Phosphate > Amino = Carboxyl > Hydroxyl > Carbonyl > Sulfhydryl > Methyl (the H+ add polarity so that CH3BR is more polar than CBR)
When are sparingly soluble salts?
Solutes with a molar solubility under 0.1 M with a negative Gibb's free energy
Why is total resistance of the capillary system low when capillaries are so tiny?
There are many of them in parallel, increasing the overall cross- sectional area
What doe sit mean if a group of outcomes is said to be exhaustive?
There are no other possible outcomes
Chemiluminescence of which of the following colors corresponds to radiation with the highest frequency? A. Red B. Yellow C. Green D. Violet
Violet shortest wavelength, highest frequency
What is the formula for work dealing with gas?
W=P∆V *note: When a gas expands, we say work has been done by the gas and the work is positive. When a gas is compressed, we say work has been done on the gas and the work is negative.
What is the formula for wavenumber?
Wavenumber = 1/ wavelength
What effect would increasing each of the following have on flow rate: the radius of the tube, pressure gradient, viscosity, and length of tube
When comparing systems, flow rate would increase when increasing either the radius or the pressure gradient, but would decrease with increasing viscosity or length of the tube. However, in one singular system, where we are comparing point A in the system to point B in the same system, changing cross-sectional area has no effect.
During which electronic transitions is photon emission most common?
When electrons transition from a higher energy state to a lower energy state they will experience photon emission.
How do we calculate the position of the median?
median position = (n+1) /2 *where n is the number of data values Note: in a data set with an even number of data points, this equation will solve for a noninteger number; for example, in a data set with 18 points, it will be (18+1)/2 = 9.5. The median, in this case, will be the arithmetic mean of the ninth and tenth items in the data set when sorted in ascending order.
What are the units for concentration?
mol/L
What is the formula for molality?
molality of the solution = moles of solute/kg of solvent *Note: molality is only required for boiling point elevation and freezing point depression
What is the term for nearsightedness?
myopia; it is fixed with a diverging (concave) lens
What is the formula for calculating possible number of peptides that contain one each of n amino acids?
n! (n factorial) for n= 3, for example, n! = 3! which means that 3 x 2 x 1 = 6 possible peptides
How do we determine splitting in NMR?
n+1 rule: If a proton has n protons that are three bonds away, it will be split into n+1 peaks. Note: do NOT include protons attached to oxygen or nitrogen
What is the formula for the index of refraction?
n= c/v *where c is the speed of light in a vacuum, v is the speed of light in the medium, and n is a dimensionless quantity called the index of refraction
How do we calculate moles?
n= mass/ molar mass n=m/M
What is the equation for exponential decay?
n= n₀e^(-λt) *where n₀ is the number of undecayed nuclei at time t=0.
What does the Pauli Exclusion Principle state?
no two electrons in the same atom can have the same set of four quantum numbers
What stabilizes tertiary structure of proteins?
non-covalent molecular interactions from the side chains and hydrophobic interactions R group interactions that contribute to tertiary structure include hydrogen bonding, ionic bonding, dipole-dipole interactions, and London dispersion forces - basically, the whole gamut of non-covalent bonds.
An opera singer ahs two precisely identical glasses. The singer produces a pure a tone as possible and shatters the first glass at a frequency of 808 Hz. She then sings a frequency of 838 Hz in the presence of the second glass. The second glass will likely...
not shatter because the applied frequency is not equal to the natural frequency of the glass. If she produced a frequency that is not equal to the natural frequency of the glass, then the applied frequency will not cause the glass to resonate, and there will not be the increase in wave amplitude associated with resonating objects.
Deprotonating a molecule makes it more...
nuclephilic
Is H2SO4 an oxidizing or reducing agent?
oxidizing
Is PCC an oxidizing or reducing agent?
oxidizing (named pyridinium chlorochromate)
What is the formula for density?
p= m/V
What is the formula for dipole moment?
p=qd
What is the formula comparing pH and pOH?
pH +pOH= 14 *as pH increases, pOH decreases by the same amount
What is the formula for pH?
pH=-log[H+]
What is the formula for pOH?
pOH = -log[OH-]
Glucose reabsorption in the nephron occurs in the...
proximal tubule
What is the formula for heat transfer (the heat absorbed or released in a given process)?
q=mc∆T Hint: "q=MCAT"
How do we compare the heat absorbed or released between two objects?
qcold= -qhot *this is because the cold object gains heat while the hot object loses it
What are vectors
quantities that have magnitude and direction ex: displacement, velocity, acceleration, and force.
List the vessels in the renal vascular pathway, starting from the renal artery and ending at the renal vein.
renal artery --> afferent arteriole --> glomerulus --> efferent arteriole --> vasa recta --> renal vein
What is the heat of fusion?
the amount of energy required to change a substance from the solid phase to the liquid phase at its melting point.
Field lines for a positive charge:
they point away from the atom
Field lines for a negative charge:
they point into the atom
What is the most stable conformation of cyclohexane?
the chair formation; it minimizes all three types of strain
hydrolysis
the chemical breakdown of a compound due to reaction with water.
Gauge pressure
the difference between the actual pressure and the atmospheric pressure
What is terminal velocity?
the greatest velocity a falling object reaches: An object in free fall will experince a growing drag force as the magnitude of its velocity increases. Eventually, this drag force will be equal in magnitude to the weight of the object and the object will fall with constant velocity. According to Newton's first law. This velocity is called the terminal velocity.
What is gram equivalent weight? How is it calculated?
the measure of the mass of a substance that can donate one equivalent of the species of interest gram equivalent weight= mass of compound (g)/ n (equivalents)
What is the coordination number?
the number of ions of opposite charge that surround the ion in a crystal. So in CH4 the coordination number is 4
What is the atomic number?
the number of protons in an atom
What is the mass number
the number of protons plus neutrons
What is benefience?
the obligation to act in the patient's best interest
What does pro- mean?
three carbons
What is deposition?
transition from gas to solid
What is sublimation?
transition from solid to gas
What is the formula for velocity without time?
v² =v₀² + 2ax
What is the formula for angular frequency?
w= 2pif= (2pi)/T
What is a transverse wave?
waves in which the particles vibrate in an up and down motion; they oscillate perpendicular to the propagation of the wave
Is acetic acid a strong or weak acid?
weak
Is hydrofluoric acid strong or weak?
weak
What is the formula for displacement with average velocity?
x= vbar * t
What is the formula for entropy of the universe?
∆Suniverse= ∆Ssytem+∆Ssurroundings > 0 *note that the entropy of a system and its surroundings will never decrease; it will always either increase or remain zero
What is the standard change in entropy formula ?
∆S°rxn= ∑S°f,products -∑S°f,reactants
What is the emperical formula?
the simplest whole number ratio of the elements in a compound. For example, writing CH instead of C6H6 (C6H6 is the molecular formula as it gives the actual numbers)
What is convection?
the transfer of heat by the physical motion of fluid over a material. Because convection involves flow, only liquids and gases can transfer heat by this means.
What is the formula for mole fraction?
XA= moles of A/total moles of all species
What does it mean for a reaction to be stereospecific?
You can only get one product from the reaction. You get a specific product
What is an isothermal process?
a process that occurs with no change to internal energy (occurs at constant temp). Here ∆U=0 and thus Q=W *note this is because temperature and internal energy are directly proportional
What is a racemic mixture?
a racemic mixture contains equal amounts of both (+) and (-) enantiomers and thus has no optical activity
What is an aqueous solution?
a solution in which the solvent is water
protic
a solvent with a hydrogen attached to a highly electronegative atom
standing wave
a wave that appears to stand in one place, even though it is really two traveling waves interfering as they pass through each other --same amplitudes with opposite direction
Would acid dissolve better in aqueous acid or aqueous base?
aqueous base
What is the formula for the location of dark fringes (minima) in a slit lens set up
asinθ=nλ *where a is the width of the slit, θ is the angle between the line drawn from the center of the lens to the dark fringe and the axis of the lens, n is the integer indicating the number of the fringe, and λ is the wavelength of the incident wave Note bright fringes are halfway between dark fringes
intermolecular forces
attractive forces between different particles.
How do simple machines make work easier?
by using a smaller force through a greater distance. The factor of force required decreases as the factor of distance is increased
What is the formula for the speed of light?
c = λv
What is the formula comparing wavelength and frequency?
c= ƒλ
Stereogenic center
carbon with 4 different groups attached to it. doesn't have a symmetric plane. chiral
What are materials that offer almost no resistance to electric flow called? What about those that offer very high resistance? What about those that fall somewhere in the middle?
conductors; insulators; resistors
Converging lenses are
convex
What is the formula relating the frequency and length of a standing wave on a closed pipe?
f= (nv)/4L *where n is the harmonic
What is the formula for the focal length of a spherical mirror?
f= r/2
What is the function of a lipase?
fat digestion: hydrolysis of triacylglycerides
What stabilizes secondary structure of proteins?
hydrogen bonds
What is the term for farsightedness?
hyperopia; it is fixed with a converging (convex) lens
as electronegativity increases, acidity
increases
What do we use to calculate angles?
inverse sine (sin^-1); inverse cosine (cos^-1); or inverse tangent (tan^-1)
What are calorimeters an example of?
isolated systems
What happens when an alcohol is oxidized?
it becomes a carbonyl
What makes a molecule organic?
it contains carbon
Atomic oxygen is extremely reactive and not found in any significant quantity on earth's surface because
it is a free radical.
Given 1atm, what is the pressure in Pa, mmHg, and torr?
1 atm= 1.013E5 Pa = 760 mmHg = 760 torr
What are combustion reactions?
A combustion reaction is a special type of reaction that involves a fuel -usually a hydrocarbon- and an oxidant (normally oxygen). In its most common form, these reactants form the two products of carbon dioxide and water. Again, combustion involves oxidation (using O2 or similar) of a fuel (typically a hydrocarbon)
What does the first-order rate law tell us about a reaction?
A first order rate law with a single reactant suggests that the reaction begins when the molecule undergoes a chemical change all by itself, without a chemical interaction, and usually without a physical interaction with any other molecule
What is a first-order reaction?
A first-order reaction has a rate that is directly proportional to only one reactant, such that doubling the concentration of that reactant results in a doubling of the rate of formation of the product. For a reaction that is: aA +bB → cC + dD the rate law for a first-order reaction is: rate= k [A]^1 or rate= k [B]^1 *k has the units s^-1 A classic example of a first-order reaction is the process of radioactive decay.
What is a zero order reaction?
A zero-order reaction is one in which the rate of formation of a product is independent of the changes in concentrations of any of the reactants. These reactions have a constant reaction rate equal to the rate constant (rate coefficient), k. For a reaction that is: aA +bB → cC + dD The rate law for a zero-order reaction is: rate= k [A]^x[B]^y *k has units M/s Note: temperature and the addition of a catalyst are the only factors that can change the rate order of a zero-order reaction. Look at the picture of the graph, rate= -slope
What are double replacement experiments?
Aka metathesis reactions, in these reactions elements from two different compounds, swap places with each other to form two new compounds. This type of reaction occurs when one of the products is removed from the solution as a precipitate or gas or when two of the original species combine to form a weak electrolyte that remains undissociated in solution. Ex: When solutions of calcium chloride and silver nitrate are combined, insoluble silver chloride forms in a solution of calcium nitrate.
What is the frequency factor
Aka the attempt frequency of the reaction, it is a measure of how often molecules in a certain reaction collide, with the units s^-1
What is buoyant force?
the upward force exerted by a fluid on a submerged object; it is equal to the weight of the fluid that the object displaces. One way to conceptualize the buoyant force is that it is the force of the liquid trying to return to the space from which it was displaced, thus trying to push the object up and out of the water. This is an important concept because the buoyant force is due to the liquid itself, not the object. If two objects placed in a fluid displace the same volume of fluid, they will experience the same magnitude of buoyant force even if the objects themselves have different masses.
Draw Methanol
CH3OH (meth meaning one carbon)
What is the activation energy?
The minimum energy of collision necessary for a reaction to take place (aka Ea or "the energy barrier").
What is the Arrhenius equation?
k=Ae^(-Ea/RT) * where k is the rate constant of the reaction, A is the frequency factor, Ea is the activation energy of the reaction, R is the ideal gas constant, and T is the temperature
Describe the (E) and (Z) forms of molecules
(E) and (Z) nomenclature is used for compounds with polysubstituted double bonds. To determine the (E)/(Z) designation, one starts by identifying the highest-priority substituent attached to each double-bonded carbon using the Cahn-Ingold-Prelog priority rules. The alkene is named (Z) if the two highest priority substituents on each carbon are on the same side of the double bond and (E) if they are on opposite sides. Z = "z"ame side and E= "e"pposite side
What is the direction of magnetic force on a moving ion?
A magnetic force acts on a moving charge in a direction that is perpendicular to both the velocity of the charge and the direction of the magnetic field.
What is a positive control?
A positive control is a test using a substance known to produce a positive result. Testing the positive control allows you to see how to visualize a positive result and ensures that the reagents and protocols are working properly
What does a positive value for "o" mean in terms of lenses? A negative?
A positive value means that the object is on the same side of the light source. A negative value means that the object is on the opposite side of the lens from the light source. --This is true for mirrors as well
What is a primary amine? Secondary? Tertiary?
A primary amine is only directly connected to one R group. A secondary amine is directly connected to 2 R-groups A tertiary amine is connected to 3 R-groups
What is an isobaric process?
A process in which pressure remains constant as volume changes, the area under the graph will be a rectangle of length P and width width ∆P. Here work can be calculated as: W=P∆V
Kinetic control
A reaction in which the product ratio is determined by the rate at which the products are formed.
Thermodynamic control
A reaction in which the product ratio is determined by the relative stability of the products.
What do the sign and scale of the exponents of Keq tell us?
A reaction that strongly favors products will have a large, positive exponents, and the larger the exponent the less reactant that will present in equilibrium. In other words, a large positive exponent indicates a reaction that foes almost to completion. On the other hand, a large negative exponent indicates a reaction that strongly favors reactants at equilibrium. In this case, only a small amount of reactant is converted to product. When performing equilibrium calculations, a Keq much less than 1 allows a very convenient and very necessary short cut to be used: the amount that has reacted can be considered negligible compared to the amount of reactant that remains.
Describe rechargable cells
A rechargeable cell or rechargeable battery is one that can function as both a galvanic and electrolytic cell.
What is the direction of current in a recharging cell?
A recharging cell is called a electrolytic cell. When these batteries are being recharged, an external voltage is applied in such a way to drive current toward the positive end of the secondary battery.
What is a magnetic field?
A result of moving charge. The SI unit for magnetic field strength is "tesla" (T), where 1 T= 1 (N*s)/ m*C
What is mass?
A scalar quantity that describes the amount of matter in an object. It would be the same on earth and the moon. (kg)
What is Graham's Law? Write the equation
Graham's law describes the behavior of gas diffusion or effusion, stating that gases with lower molar masses will diffuse or effuse faster than gases with higher molar masses at the same temperature: r₁/r₂ = sqrt(M₂/M₁) *where r₁ and r₂ are the diffusion rates of gas 1 and gas 2 respectively and M₁ and M₂ are the molar masses of gas 1 and gas 2 respectively.
If methane and isobutane are placed in the same container under the same conditions, which will exert the higher pressure (consider both as having negligible attractive forces)?
Isobutane is larger and will thus have a larger correction term for the size of the molecule, b. This makes V-nb smaller. The pressure or volume must rise to compensate. Because the two gases are in the same size container, isobutane must exert a higher pressure.
How to name extended polyatomic anions
In extended series of oxyanions, prefixes are also used. Hypo- and hyper, written as per-, are used to indicate less oxygen and more oxygen. Ex:) ClO- hypochlorite ClO2- chlorite ClO3- chlorate ClO4- perchlorate
What factors affect the stability of cyclic organic compounds?
In general, small rings (containing less than 5 carbons) are extremely unstable due to both torsional an angle strain.
How are significant digits determined in measurements?
In measurements, the last digit is usually an estimation and is not considered significant.
What is the oxidation number of oxygen?
In most compounds, the oxidation number of oxygen is -2. The two exceptions are peroxides (O2,2-), for which the charge on each oxygen is -1, and compounds with more electronegative elements such as OF2, in which oxygen has a +2 charge.
What are spectator ions?
Ions that don't take part in the overall reaction but simply remain in the solution unchanged. They are present in complete ionic equations but not net ionic equations.
Describe isoelectric focusing
Isoelectric focusing is a technique used to separate amino acids or polypeptides based on their isoelectric points (pI). The positively charged amino acids (protonated at the solution's pH) will migrate toward the cathode; negatively charged amino acids (deprotonated at the solution's pH) will migrate toward the anode.
Describe the common ion effect
It is the fact that the solubility of a salt is considered reduced when it is dissolved in a solution that already contains one of its constituent ions as compared to its solubility in a pure solvent. Note, however, that the presence of the common ion has no effect on the value of the solubility product constant itself. --molar solubility is reduced while Ksp remains constant
How do you calculate the coefficient of friction?
It is the frictional force divided by the normal force
What is conductivity?
It is the reciprocal of resistance and is a measure of permissiveness to current flow. It is measured in siemens (S)
What is the role of histidine tagging in separation and purification?
It is used for affinity column chromatography
What is a dipole?
It results from two equal and opposite charges being separated a small distance d from each other. It can be transient (as in the case of moment-to-moment changes in electron distribution that create London dispersion forces) or permanent (as in the case of the molecular dipole of water or the carbonyl function group)
Describe Avogadro's principle and write the equation
It states that all gases at the same temperature and pressure will occupy equal volume. n/V=k or n1/V1 = n2/V2 *where k is a constant
What is Kirchhoff's loop rule?
It states that around any closed loop, the sum of voltage sources will always be equal to the sum of voltage (potential) drops. This is a consequence of the conservation of energy. All the electrical energy supplied by a source gets fully used by other elements within that loop. No excess energy appears, and no energy disappears that cannot be accounted for. Of course energy can be changed from one form to another, so the KE of the electrons can be converted to thermal energy, light, or sound by the particular apparatus that is connected to the circuit. Remember that although Kirchhoff's loop rule is a consequence of the law of conservation of energy, this law is in terms of voltage (joules per coulomb), not just energy (joules). This can be expressed mathematically as: Vsource= Vdrop
What is Kirchhoff's Junction Rule?
It states that at any point or junction in a circuit, the sum of currents directed into that point equals the sum of currents directed away from that point. This is an expression of conservation of electrical charge and can be expressed as : Iinto the junction= Ileaving the junction
What is the work-energy theorem?
It states that the net work done by forces acting on an object will result in an equal change in the object's kinetic energy. In other words Wnet= ∆ KE= Kf-Ki pg62 of math and phys if needed
Describe Boyle's law. What is the equation?
It states that the pressure of a gas is inversely related to its volume: PV=k or P1V1=P2V2 *where k is a constant
What happens when an amino acid is phosphorylated?
It takes on a negative charge. This typically happens with STY (serine, threonine, and tyrosine) on their hydroxyl side chains
What is the IR absorption frequency for a carbonyl ?
It will be a sharp peak at around 1700 cm^-1
Where do we find the peak of a carbonyl function group?
It will be sharp peak at around 1700 cm^-1
Describe the possible changes in Gibb's free energy and what they mean
It's all about reaching equilibrium. Movement toward the equilibrium position is associated with a decrease in Gibbs free energy (∆G<0) and is spontaneous. When a system releases energy, it is said to be exergonic--Gibbs free energy decreased because it was being released. On the other hand, movement away from the equilibrium position is associated with an increase in Gibbs free energy (∆G >0) and is nonspontaneous. Such a reaction is said to be endergonic--the energy available to do work increased because the reaction took in energy. Once at the energy minimum state --equilibrium--the system will resist any changes to its state, and the change in free energy is 0. (If ∆G is zero, the system is in a state of equilibrium; ∆H=T∆S)
What is the sin of 0 degrees?
0
What is the sin of 180 degrees?
0
What is the tan of 180 degrees?
0
What is the tangent of 0 degrees?
0
What is the oxidation number of a free element?
0 For example, the atoms in N2, P4, S8, and He all have oxidation numbers of zero.
What is the log of 1?
0 It's the opposite of the fact that 10^0 = 1 (any number to the zeroth power = 1)
What is the formula for static friction?
0≤fs≤µsN where µs is the unitless coefficient of static friction and N is the normal force Note the less-than-or-equal-to signs in the equation. These signify that there is a range of possible values for static friction. The minimum, of course, is zero. This would be the case if an object were resting on a surface with no applied forces. The maximum value of static friction can be calculated from the right side of the equation. One should not assume that objects that are stationary are experiencing maximal static force of friction. Consider trying to push a heavy piece of luggage. When a 25 N force is applied, the bag does not move. When a 50N force is applied, the bag still does not move. When a 100N force is applied, the bag slides a meter or so and slows to a rest. This setup implies that the maximal value f static friction is somewhere between 50 and 100N; any applied forces less than this threshold will not be sufficient to move the bag as there will be an equal but opposite force of static friction opposing the bag's motion.
For problems involving the determination of the limiting reagent, what are the two principles we must keep in mind?
1. All comparisons of reactants must be done in units of moles. Gram-to-gram comparisons will be useless and may even be misleading. 2. It is not the absolute mole quantities of the reactants that determine which reactant is the limiting reagent. Rather, the rate at which the reactants are consumed (the stoichiometric ratios of the reactants) combined with the absolute mole quantities determines which reactant is the limiting reagent.
What is the IR absorption frequency for an O-H ?
it will be a broad peak at around 3300 cm^-1 for alcohols or 3000 cm^-1 for carboxylic acids *The carbonyl of a carboxylic acid pulls some of the electron density out of the O-H bond, shifting the absorption to a lower wave number
What is percent composition? How is it calculated?
the percent of a specific compound that is made up of a given element. It is calculated by: percent composition = (mass of element in formula/ molar mass) * 100 % Note: One can calculate the percent composition of an element by using either the emperical or the molecular formula. It is also possible to determine the molecular formula given both the percent compositions and molar mass of a compound.
equivalence point
the point at which the two solutions used in a titration are present in chemically equivalent amounts
What is Lorentz force?
the sum of electrostatic and magnetic forces acting on an object
What is the resultant? How is it calculated?
the sum of two or more vectors. It can be calculated using two methods: *one method of adding vectors is the tip-to-tail method *another method for finding the resultant is breaking each vector into perpendicular components
What is the triple point?
the temperature and pressure at which all three phases of matter coexist in an equilibrium
What is the critical point?
the temperature and pressure at which liquids and gases become indistinguishable The heat of vaporation at this point and for all temperatures and pressures above this point is 0
What is absolute (aka hydrostatic) pressure? How is it calculated?
the total pressure that is exerted on an object that is submerged in a fluid; it is equal to pressure at the surface of the fluid (usually atmospheric pressure) plus the pressure due to the fluid itself P= P0 + density(g)z *z is the depth of the object *P is the absolute pressure *P₀ is the incident or ambient pressure (the pressure at the surface)
What makes a substance soluble?
Its ability to have intermolecular interactions with water -- form hydrogen bonds
What is the SI unit for energy?
Joule (J) --> (kg*m²)/ s²
Formula comparing the acid dissociation constant to the dissociation constant of its conjugate base and the base dissociation constant to its conjugate acid
Ka,acid x Kb,conjugate base = Kw = 10^-14 Kb,base x Ka, conjugate acid = Kw= 10 ^-14
What is the formula for the acid dissociation constant?
Ka= ([H₃O+][A-])/ [HA] *this is only used for weak acids. The smaller the Ka, the weaker the acid, and consequently, the less it will dissociate
What is the formula for the base dissociation constant?
Kb= ([B+][OH-])/ [BOH] *this is only used for weak bases. The smaller the Kb, the weaker the base, and consequently, the less it will dissociate
What is the formula for Kequilibrium?
Keq= kf/k/r= [products]^x/ [reactants]^y
How are ketones named?
Ketones are named by replacing the -e with the suffix -one. When naming ketones by their common names, the two alkyl groups are named alphabetically, followed by -ketone. When ketones are named as substituents, use either the prefix oxo- or keto-.
What is kinetic friction and how is it calculated?
Kinetic friction exists between a sliding object and the surface over which it slides. It is calculated by: fK=µkN Note: wheel roiling along the road does not experience kinetic friction (fK) because it is not sliding along the pavement. It maintains an instantaneous point of static contact with the road and thus experiences fs. If it were to slide on ice then it would be fK.
What is the first law of thermodynamics?
The 1st law of thermodynamics accounts for the conservation of mechanical energy which states that energy is never created nor destroyed, it is transformed from one form to another. -- mechanical energy can be "lost" to heat due to friction however so it may not stay constant. This is shown by the formula: ∆U = Q- W
What is the third law of thermodynamics?
The 3rd law of thermodynamics states that the entropy of a perfectly organized crystal at absolute zero is zero.
What's the difference between Bronsted-Lowry and Lewis acids and bases?
The Bronsted-Lowry definition revolves around protons; the Lewis definition around electrons.
Describe the distal convoluted tubule
The DCT responds to aldosterone, which promotes sodium reabsorption. Because sodium ions are osmotically active particles, water will follow the sodium, concentration the urine and decreasing its volume. The DCT is also a site of waste product secretion like the PCT.
What has to happen for amide to be hydrolyzed by water?
The carbonyl O must be protonated, so it would have to take place in highly acidic conditions. This reaction can take place in super basic conditions as well but the nucleophile will be -OH instead and the product would be a deprotonated carboxylate anion. *has to be highly acid or highly basic conditions
What is the half equivalence point?
The center of the buffering region where [HA] = [A-].
What are the rays we draw for a concave mirror?
There are 3: 1. A ray that strikes the mirror parallel to the axis (the normal passing through the center of the mirror) is reflected bac through the focal point. 2. A ray that passes through the focal point before reaching the mirror is reflected bac parallel to the axis. 3. A ray that strikes the center of the mirror and reflects back at the same angle relative to normal.
Describe paramagnetic materials
These are materials with atoms that have unpaired electrons, thus they have a net omagnetic dipole moment, however, the atoms in these materials are usually randomly oriented so that the material itself creates no net magnetic field. Paramagnetic materials will become weakly magnetized in the presence of an external magnetic field, aligning the magnetic dipoles of the material with the external field. Upon removal of the external field, the thermal energy of the individual atoms will cause the individual magnetic dipoles to reorient randomly.. Some paramagnetic materials include aluminum, copper, and gold.
Describe Ruffini endings.
These are sensory receptors located in the dermis that respond to stretch
Describe Merkel cells (discs)
These are sensory receptors present at the epidermal-dermal junction. These cells are connected to sensory neurons and are responsible for deep pressure and texture sensation with the skin.
What are decomposition reactions
They are the opposite of combination reactions a single reactant breaks down into two or more products, usually as a result of heating, high frequency radiation, or electrolysis. A---> B + C
Describe the Bowman's capsule
This is a cuplike structure around the glomerulus. Bowman's capsule leads to a long tubule with many distinct areas; in order, these are the proximal convoluted tubule, descending and ascending loops of Henle, distal convoluted tubule, and collecting duct.
Describe LiAlH4
This is a very strong reducing agent that turns carbonyls into alcohols --ALL carbonyls
What is the mnemonic for image types with a single lens or mirror (assuming o is positive)?
UV NO IR Upright images are always virtual No image is formed with the object is a focal length away Inverted images are always real
When do we use UV spectroscopy?
UV spectroscopy is most useful for studying compounds containing double bonds or heteroatoms with lone pairs that create conjugated systems
Describe an ohmmeter
Unlike ammeters and voltmeters, ohmmeters do not require a circuit to be active (in fact, some ohmmeters will give false readings or can be damaged by an active circuit). Ohmmeters will often have their own battery of known voltage and then function as ammeters through another point in the circuit. Because only one circuit element is being analyzed, Ohm's law can be used to calculate resistance by knowing the ohmmeter's voltage and the current created through another point in the circuit. Thus, ohmmeters are inserted around a resistive element to measure resistance they are self-powered and have negligible resistance.
What are configurational isomers?
Unlike conformational isomers that interconvert by simple bond rotation, configurational isomers can only change from one form to another by breaking and reforming covalent bonds. The two forms of configurational isomers are enantiomers and diastereomers. Both enantiomers and diastereomers can be considered optical isomers because the different aptial arranfement of groups in these molecules affects the rotation of plane-polarized light.
What is the strength of using the median for analysis?
Unlike the mean, the median tends to be the least susceptible to outliers. However, it may not be useful for data sets with very large ranges or multiple modes.
Shock waves have the greatest impact when the source is traveling...
exactly at the speed of sound Shock waves are the buildup of wave fronts as the distance between those wave fronts decreases. This occurs maximally when an object is traveling exactly the same speed of sound as the wave is traveling the speed of sound. Once an object moves faster than the speed of sound, some of the effects of the shock wave are mitigated because all of the wave fronts will trail behind the object, destructively interfering with each other.
What is the formula relating the frequency and length of a standing wave on a string?
f= (nv)/2L *where n is the harmonic
What is the equation for beat frequency
fbeat= |f1-f2|
What is the NMR for Aldehydes?
9 to 10 ppm
How do you solve logA^B?
As BlogA
How can we use equivalence point to tell the strength of the acids and bases being mixed in titration?
*Strong Acid + weak base: equivalence point pH < 7 *Strong acid + strong base: equivalence point = 7 *weak acid + strong base: equivalence pH >7
What is the oxidation number of a Group IA element in a compound?
+1
What is the cosine of 180 degrees?
-1
What is the oxidation number of each group VIIA element in a compound?
-1 ; except when combined with an element of higher electronegativity. For example, in HCL, the oxidation number of Cl is -1; in HOCl, however, the oxidation number of Cl is +1. *going up the periodic table has a greater increase in electronegativity than going across.
A charge of 2uC flows from the positive terminal of a 6 V battery, through a 100 ohm resistor, and back through the battery to the positive terminal. What is the total potential difference experienced by the charge?
0 V Kirchhoff's loop rule states that the total potential difference around any closed loop of a circuit is 0V. Another way of saying this is that the voltage gained din the battery (6V) will be used up through the resistors. Because this charge both started and ended at the positive terminal, its total potential difference is therefore 0V. 6V, is the voltage gained in the battery as well as the voltage dropped in the resistors --creating a net sum of 0V.
What is the cosine of 90 degrees?
0 degrees
What is velocity at maximum height of a projectile?
0 m/s
What is the NMR for alkyl goups?
0 to 3 ppm
What is the molar concentration of Na+(aq) in a solution that is prepared by mixing 10 mL of a 0.010 M NaHCO3(aq) solution with 10 mL of a 0.010 M Na2CO3(aq) solution?
0.015 mole/L Since 1 equivalent of NaHCO3 provides 1 equivalent of Na+, the molar concentration of Na+(aq) in 0.010 M NaHCO3(aq) solution is also 0.010 M = 0.010 mole/L. The molar concentration of Na+(aq) in 0.010 M Na2CO3(aq) solution is 0.020 mol/L since 1 equivalent of Na2CO3 provides 2 equivalents of Na+. When equal volumes of these two solutions are mixed, the resulting molar concentration is equal to their average, (0.010 mol/L + 0.020 mol/L)/2.
What is the ideal gas constant?
0.0821 (L*atm)/ (mol*K)
What is the sin of 30 degrees?
0.5
How much volume does a mole at STP occupy?
22.4 L
What are standard conditions?
25 degrees celsius (298K), 1 atm pressure, and 1 M concentrations
Objects A and B are submerged at a depth of 1 m in a liquid with a specific gravity of 0.877. Given that the density of object B is one-third that of object A and that the gauge pressure of object A is 3atm, what is the gauge pressure of object B? Explain the answer.
3 atm The absolute and gauge pressure depend only on the density of the fluid, not of the object. When the pressure at the surface is equal to atmospheric pressure, the gauge pressure is given by Pgauge= rho*g*z, where rho represents the density of the fluid, not the object. These objects are also at the same depth, so they must have the same gauge pressure.
What is the speed of light?
3.00 x 10^8 m/s
What is the speed of sound through air at 20 degrees celsius?
343 m/s
What is the NMR for Alkenes?
4.6 to 6 ppm
What are the boundaries of the visible spectrum?
400-700 nm
0.44 moles of AgNO3 and 0.20 moles of MgCl2 are mixed together. What is the mass percent composition of Ag in the product?
75.2% The starting number of moles is irrelevant information when calculating the mass percent composition. The products of the reaction are AgCl and Mg(NO3)2. Since the question stem asks about the mass percent composition of Ag, the product of interest is AgCl. It does not matter how many moles of AgCl are formed; there will always be 107.9g of Ag per mole and 35.5 g of Cl per mole of product, since those are the molar masses of Ag and Cl, respectively. The total mass of AgCl is 143.3 g/mol, so the mass percent composition of Ag is 107.9/143.3 or 75.2%.
What is Coulomb's constant
8.99E9 (N*m²)/ C²
What is a cell diagram and how is it read? Use Zn(s) | Zn2+ (1M) || Cu2+ (1M) | Cu (s) to explain
A cell diagram is a shorthand notation representing the reactions in an electrochemical cell. The following rules are used in constructing a cell diagram: 1. The reactants and products are always listed from left to right in this form: anode | anode solution (concentration) || cathode solution (concentration) | cathode 2. A single vertical line indicates a phase boundary 3. A double vertical line indicates the presence of a salt bridge or some other type of barrier
What is the equation for the concentration of radioactive substance A at any time t?
A classic example of a first-order reaction is the process of radioactive decay. The equation is as follows: [A]t = [A]0e^(-kt) *Where [A]t is the concentration of A at time t, [A]0 is the initial concentration of A, k is the rate constant, and t is time
what kind of calorimeter is a coffee cup calorimeter?
A constant-pressure calorimeter
What type of calorimeter is a bomb calorimeter?
A constant-volume calorimeter
How does the strength of a strong acid/ base compare to its conjugate?
A strong acid will produce a very weak conjugate base, and a strong base, will produce a very weak conjugate acid
What qualities must a study have to provide justification for intervention?
A study must have both statistical significance and clinical significance to provide justification for intervention. A study without statistical significance may be the result of random chance, whereas one without clinical significance will not impact patients.
What type of enzyme is a kinase?
A transferase
Nucleophile
An atom (or group of atoms) that is attracted to an electron- deficient centre or atom, where it donates a pair of electrons to form a new covalent bond.
What is adhesion?
An attraction between molecules of different substances
What is the empirical formula?
An empirical formula is the simplest ratio of whole number atoms of each element in a compound.
What does a negative change in enthalpy indicate?
An exothermic reaction
How do you solve logA x B?
As logA x logB
Describe the relationship between specific gravity and floating.
Any object with a specific gravity less than or equal to to 1 will float in water and any object with a specific gravity greater than 1 will sink in water. A specific gravity of exactly 1 indicates that 100 percent of the object will be submerged but it will not sink. Note: in the case of pure water, an object's specific gravity as a percent is how much of the object will be under water
How do we identify outliers with an IQR?
Any value that falls more than 1.5 interquartile ranges below the first quartile or above the third quartile is considered an outlier. Do 1.5 * IQR
How do you solve LogA/B?
As logA- logB
What is the formula for calculating the magnetic field from a loop of wire?
B = µ₀I / 2r *where B is the magnetic field at a distance r from the wire, µ₀ is the permeability of free space, and I is the current.
What is the formula for calculating the magnetic field from a straight wire?
B = µ₀I / 2πr *where B is the magnetic field at a distance r from the wire, µ₀ is the permeability of free space, and I is the current.
What are the metalloids?
B, Si, Ge, As, Sb, Te, At Big Sized Genitals Assure Some Terrible Accidents
Describe bias in research in terms of accuracy and precision
Because bias is a systemic error in data, only an inaccurate tool will introduce bias, but an imprecise tool will still introduce error.
What is the difference between bias and confounding?
Bias is a systemic (unidirectional) error that occurs during the selection of subjects or the measurement and collection of data. Confounding is an error that occurs during data analysis, in which an association is erroneously drawn between two variables because of a shared connection to a third variable.
How des the transition state theory compare with the collision theory of chemical kinetics?
Both theories require a certain activation energy to be overcome in order for a reaction to occur (therefore not all reactions will occur). The transitions state theory focuses on forming a high-energy activated complex that can then proceed forward or backward, forming the products or reverting to the reactants, respectively. The collision theory focuses on the energy and the orientation of reactants, and considers each potential reaction to be "all-or-nothing" (either there is enough energy to form the products, or there is not).
How can we find the sqrt of a large number?
Break it up into smaller square roots. For example: sqrt (180)= sqrt (4) * sqrt (5) 8 sqrt (9) = 2 * sqrt (5) * 3 = 6sqrt(5)
Under normal physiological circumstances, the primary function of the nephron is to create urine that is: a. hypertonic to the blood b. hypotonic to the blood c. isotonic to the filtrate d. hypotonic to the vasa recta
By the end of the nephron, a lot of water should be reabsorbed form the filtrate so urine should be hypertonic to the filtrate.
What is the formula for capacitance involving the permittivity of free space, the are of overlap, and the separation of the plates?
C = ε₀(A/d) * where ε₀ is the permittivity of free space, A is the area of overlap of the two plates, and d is the separation of the two plates
What is the formula for the capacitance due to a dielectric material?
C'= κC *note that incorporating the dielectric constant into the basic equation for capacitance reveals that "capacitors are CAκεd with charge (C=Aκε/d)"
What is the formula for electric field involving voltage?
E= (V- IR/L)
A scientist wishes to test the effects of various solutes on osmotic pressure. She has two chambers filled with distilled water and separated by a semipermeable membrane. In each trial, she adds .2 moles to one of the chambers and measures the osmotic pressure. Which of the following solutes will produce the greatest change in osmotic pressure? A. NaCl B. HCO3- C. CaCl2 D. Glucose
CaCl2 Osmotic pressure is a colligative property, meaning it is a property that is dependent upon the number of particles present and, ideally speaking, not the identity of those particles. The answer that would affect osmotic pressure the most is the compound that would produce the greatest number of particles. Equal amounts (.2 moles) of each is added, so the number of particles will depend upon the solubility and dissociation products. Choice C will produce the greatest number of particles since it is soluble and dissociates into three particles. Choice A while soluble, sodium chloride will only dissociate into two particles. Choice B the bicarb ion is a weak acid (and weak base) and will only dissociate slightly. Choice D glucose is a covalently bond molecule that will not dissociate.
Describe capacitors
Capacitors are characterized by their ability to hold charge at a particular voltage. When two electrically neutral metal plates are connected to a voltage source, positive charge builds up on the plate connected to the positive (higher potential) terminal, and negative charge builds p on the plate connected to the negative (lower potential) terminal.
Describe the formation of cyclic anhydrides
Certain cyclic anhydrides can be formed by heating carboxylic acids. The reaction is driven forward by the increased stability of the newly formed ring; as such, only anhydrides with five- or six-membered rings are easily made. Just as with all anhydride formations, the hydroxyl group of one -COOH acts as the nucleophile, attacking the carbonyl on the other -COOH. Note: Anhydrides often have higher boiling points than their related carboxylic acids, based solely on their much greater weight.
Describe electron capture
Certain unstable radionuclides are capable of capturing an inner electron that combines with a proton to form a neutron while releasing a neutrino. The atomic number is now one less than the original but the mass number remains the same. Electron capture is a rare process that is perhaps best thought of as the reverse of beta- decay.
Describe Charles' Law and write the equation
Charles the Vth over Talks The law states that, at constant pressure, the volume of a gas is proportional to its absolute temperature, expressed in kelvins. V/T= k or V1/T1= V2/T2
What are catalysts?
Chemical agents that selectively speed up chemical reactions without being consumed by the reaction. The only effect of the catalyst is a decrease in the energy of activation, Ea for both forward and reverse reactions. The presence of the catalyst has no impact on the free energies of the reactants or the products or the difference between them. This means that catalysts change only the rates of reactions, and in fact, change the forward rate and the reverse rate by the same factor. Consequently, they have no impact whatsoever on the equilibrium position or the measurement of Keq--THEY DO NOT AFFECT FREE ENERGY. Catalysts are also unable to make a nonspontaneous reaction spontaneous.
What are chemical properties?
Chemical properties have to do with the reactivity of the molecule with other molecules and result in changes in chemical composition. IN organic chemistry, the chemical properties of a compound are generally dictated by the functional groups in the molecule.
What is the hybridization of chiral centers?
Chiral centers are sp3 hybridized and attached to 4 different compounds.
What is a complex ion?
Complex ions or coordination compounds are composed of metallic ions bonded to various neutral compounds and anions, referred to as ligands. Formation of complex ions increases the solubility of other wise insoluble ions (the opposite of the common ion effect)--page 320. The process of forming a complex ion involves electron pair donors and electron pair acceptors such as those seen in coordinate covalent bonding.
What is the difference between creation of images by convex mirrors and concave mirrors?
Concave mirrors are converging systems and can produce real, inverted images or virtual, upright images, depending on the placement of the object relative to the focal point: if the object is beyond the focal point the image will be real and inverted, if the object is on the focal point there will be no image, if the object is in front of the focal point the image will be virtual and upright. Convex mirrors are diverging systems and will only produce virtual upright images that get smaller the further away the object is.
Describe concentration cells
Concentration cells are a special type of galvanic cell. Like all galvanic cells, it contains two half-cells connected by a conductive material, allowing a spontaneous redox reaction o proceed, which generates a current and delivers energy. The distinguishing characteristic of a concentration cell is in its design: the electrodes are chemically identical. For example, if both electrodes are copper metal, they have the same reduction potential. Therefore, current is generated as a function of a concentration gradient established between the two solutions surrounding the electrodes. The concentration gradient results in a potential difference between the two compartments and drives the movement of electrons in the direction that results in equilibration of the ion gradient. The current will stop when the concentrations of ionic species in the half-cells are equal. This implies that the voltage (V) or electromotive force of a concentration cell is zero when the concentrations are equal.
In statistics what is confidence?
Confidence is the probability of correctly failing to reject a true null hypothesis (reporting no difference between two populations when one doesn't exist).
Which of the following relationships between measurement error and overall error is correct? A. Unreliable data leads to confounding B. Invalid data leads to confounding C. Unreliable data leads to bias D. Invalid data leads to bias
D. Invalid data leads to bias Data that is off in a systemic way (reads at a value that is not the true value) will cause bias. This type of data error is an example of a lack of validity (or accuracy). Unreliable data suffers from random, not systemic, error. Confounding arises from errors in data analysis, not data collection
What is direct current?
DC; Current that flows in only one direction
What is a diamagnetic material?
Diamagnetic materials are made of atoms with no unpaired electrons and that have no net magnetic field. These materials are slightly repelled by a magnet and so can be called weakly antimagnetic. Diamagnetic materials include common materials that you wouldn't expect to get stuck to a magnet wood, plastics, water, glass, and skin, just to name a few.
What is diffraction?
Diffraction refers to the spreading out of light as it passes through a narrow opening or around an obstacle. Interferences between diffracted light rays lead to characteristic fringes in slit-lens and double-slit systems.
Review page 171 mixed-order rate law
Done
How do we calculate efficiency?
Efficiency = Wout/ Win= (load)(load distance)/ (effort)(effort distance)
What is efficiency?
Efficiency is the ratio of the machine's work output to work input when non-conservative forces are taken into account.
How does the presence of halogens affect the acidity of a carboxylic acid molecule?
Electron withdrawal stabilizes the conjugate base of a carboxylic acid, the carboxylate ion, and thus the acidity of a carboxylic acid is increased by the presence of an electron-withdrawing group such as chlorine. The proximity of the electron-withdrawing group to the carboxyl group determines the degree of stabilization of the carboxylate ion. The closer it is to the carboxylic acid, the more stable the conjugate base is and thus the stronger the acid
Describe the inductive effects on acids
Electronegative elements positioned near an acidic proton increases acidic strength by pulling electron density out of the bond holding the acid proton. This weakens proton bonding and facilitates dissociation. Thus, acids that have electronegative elements nearer to acidic hydrogens are stronger than those that do not.
How do distance and charge relate to electrostatic force and electric field?
Electrostatic force is directly related to each charge and related to the distance by an inverse square relationship. Electric field is unrelated to test charge but is still related to distance by an inverse relationship. Note that it is the source charge that creates the electric field --not the test charge.
Describe enols
Enols get their name from the presence of a carbon-carbon double bond (the en- component) and an alcohol. Enols are important intermediates in many reactions of aldehydes and ketones. The enolate carbanion results from the deprotonation of the alpha-carbon by a strong base. Common strong bases include the hydroxide ion, lithium diisopropyl amide (LDA), and potassium hydride (KH). Note: a 1,3-dicarbonyl is particularly acidic because there are two carbonyls to delocalize negative charge and, as such, is often used to form enolate carbanions. Once formed, the nucleophilic carbanion reacts readily with electrophiles.
Describe entropy and Gibbs free energy in a reaction that is at dynamic equilibrium
Entropy is at a maximum and gibb's free energy is at a minimum
Describe entropy
Entropy is the measure of the spontaneous dispersal of energy at a specific temperature (how much energy is spread out or how widely spread out energy becomes in a process). When energy is distributed into a system at a given temp, it entropy increases. When energy is distributed out of a system, at a given temp, its entropy decreases.
What is a ternary complex?
Enzyme simultaneously bound to two substrates.
What is the formula for changing from Fahrenheit to Celsius?
F= (9/5)C + 32
What is the formula for magnetic force on a current-carrying wire?
FB= ILBsinθ *where I is the current, L is the length of the wire in the field
What is the formula for magnetic force on a moving point charge?
FB= qvBsinθ *where q is the charge, v is the magnitude of its velocity, B is the magnitude of the magnetic field, and θ is the smallest angle between the velocity vector v and the magnetic field B. Notice that the magnetic force is a function of the sine of the angle, which means that the charge must have a perpendicular component of velocity in order to experience a magnetic force. If the charge is moving parallel or antiparallel to the magnetic field vector, it will experience no magnetic force. This is due to the fact that sin0 and sin180 equal 0.
True or False: The sum of the voltage sources in a circuit is equal to the sum of the voltage drops in that circuit.
False. While the voltage sources and voltage drops are equal in any closed loop, this is not necessarily true for the entire circuit. For example, a 9 V battery that powers 10 light bulbs in parallel has a 9 V voltage source and a 9 V drop across each light bulb -- a total of 90V of drop across all of the light bulbs combined.
What is the formula for buoyant force?
Fb = ρ(fluid) * V (fluid displaced) * g = ρ(fluid) V(object submerged) g
What is the formula for centripetal force?
Fc = mv²/r
What is required to see an IR spectra?
For an absorbance to be recorded, the vibration must result in a change in the bond dipole moment. This means the molecules that do not experience a change in dipole moment, such as those composed of atoms with the same electronegativity or molecules that are symmetrical, do not exhibit absorption. For example, we cannot get an absorption from O2 or Br2, but we can from HCl or CO. Symmetric bonds such as the triple bond in acetylene (C2H2) will also be silent.
What causes fluorescence?
Fluorescence is a special stepwise photon emission in which an excited electron returns to the ground state through one or more intermediate excited states. Each energy transition releases a photon of light. With smaller energy transitions than the initial energy absorbed, these materials can release photons of light in the visible range. In other words, fluorescence occurs when a species absorbs high-frequency light and then return to its ground state in multiple steps. Each step has less energy than the absorbed light and is within visible range of the electromagnetic spectrum.
Describe the Venturi effect
For a horizontal flow, there is an increase relationship between pressure and speed, and in a closed system, there is a direct relationship between cross-sectional area and pressure exerted on the walls of a tube.
Describe mesocompounds
For a molecule to have optical activity, it must not only have chiral centers within it but must also lack a plane of symmetry. Thus if a plane of symmetry exists, the molecule is not optically active even if it posses chiral cents. This plane of symmetry can occur either through the chiral center or between chiral centers. A molecule with chiral centers that has an internal plane of symmetry is called a meso compound. Meso compounds are essentially the molecular equivalent of a racemic mixture.
What is the formula for determining the rate of a reaction?
For a reaction that is: aA +bB → cC + dD the equation is: rate= (-∆[A]/ a ∆t) = (-∆[B]/b (∆ t)) = (+ ∆ [C]/ c (∆ t)) = (+ ∆ [D]/ d (∆ t)) *the letters in italics are the coefficients from the equation for example in 2HCl, "2" would be "a"
What is the equation for rate law?
For a reaction that is: aA +bB → cC + dD the rate law is: rate= k [A]^x[B]^y *the "x" and "y" are based on some experimental values and "k" is a proportionality constant *only the reactants are used in a rate law
How do we determine the number of stereoisomers?
For any molecule with n chiral centers, there are 2^n possible stereoisomers
How do electrons flow in electrochemical cells?
From anode to cathode from A to C (order in the alphabet)
Which nucleotides have three bonds?
G and C
How do galvanic, concentration, and voltaic cells relate in terms of reactions?
Galvanic cells and concentration cells house spontaneous reactions, whereas electrolytic cells contain nonspontaneous reactions.
Describe gamma decay
Gamma decay is the emission of gamma-rays, which are high-energy (high-frequency) photons. They carry no charge and simply lower the energy of the parent nucleus without changing the mass number or the atomic number. The high-energy state of the parent nucleus may be represented by an asterisk.
Describe Gay-Lussac's Law. Write the equation
Gay-Lussac's law is a special case of the ideal gas law for which volume and number of moles are held constant; it shoes a direct relationship between temperature and pressure: P/T=k or P1/T1= P2/T2 *where k is a proportionality constant
In a neutral solution, a region of a protein has a solvation nshell with the hydrogens of water directed towards the protein. Which of the following are most likely to predomiante in the segment? A. Phenylalanine and tyrosine B. Hisidine and lysine C. Alanine and teyptophan D. Glutamic acid and aspartic acid
Glutamic acid and aspartic acid SInce the hydrogens are directed twards the protein, it can be reasonably concluded that the region is predominantly negatively charged.
What are the two main examples of conservative forces?
Gravity and electrostatic forces
Name 4 ions that are always soluble
Group I metal, ammonium, nitrate, and acetate salts are always soluble
How do substituents affect the acidity of a carboxylic acid?
Groups like -NO2 or halides are electron withdrawing and increase acidity. In contrast, -NH2 or -OCH3 are EDG that destabilize the negative charge, decreasing the acidity of the compound. The closer the substituent groups are to the carboxyl group, the greater the effect will be.
What is heat?
Heat (Q) is the transfer of energy from one substance to another as a result of their differences in temperature. Heat is therefore a process function, not a state function.
Describe Henry's law and write the equation for it
Henry's law states that the amount of gas dissolved in solution is directly proportional to the partial pressure of that gas at the surface of a solution: [A]= kH x PA or [A]₁/P₁ = [A]₂/P₂ *where [A] s the concentration of A in solution and kH is Henry's constant. This, the solubility of a gas will increase with increasing partial pressure of the gas.W
A scientist uses thin-layer chromatography on silica plates to separate a mixture of phenylalanine and tyrosine. Does phenylalanine have a higher or lower Rf than tyrosine?
Higher, because tyrosine is more polar than phenylalanine Silica plates are very polar, thus the stationary phase is polar. Molecules with an affinity for polar phases will have a lower Rf. Since tyrosine is more polar (due to the additional hydroxyl group) it will have a greater preference for the stationary phase than phenylalanine, and phenylalanine will have a higher Rf.
What is the radius of curvature?
How far the center of curvature is from the mirror
Describe hydrogen bonds
Hydrogen bonding involves a highly electronegative atom (F,O,B) and a hydrogen. It is a noncovalent bond. It causes increased melting points, boiling points, and solubility in water.
By what method does proteolytic cleavage take place?
Hydrolysis Thus peptide bonds are FORMED via hydration
If the surface area of electrode material in an electrochemical cell is tripled, what else is necessarily tripled? I. E°cell II. Current III. Keq
II only Potential as measured by E°cell is dependent only on the identity of the electrodes and not the amount present. Similarly, the equilibrium constant depends only on the identity of the electrolyte solutions and the temperature. However, as the electrode material is increased, the surface area participating in oxidation-reduction reactions is increased and more electrons are released, making statement II correct.
What is standard temperature and pressure?
STP 0 degrees celcius (273 K) and 1 atm
Describe hydroxyquinone
Hydroxy quinone contains two carbonyls and a variable number of hydroxyl groups. Hydroquinones behave like quinones with electron-donating groups, making these slightly less electrophilic (though still highly reactive)
What is the formula for sound intensity?
I = P/A *where P is the power and A is the area. The SI units are W/m²
Which if the following will affect the frequency of sound waves travelling through air, as measured by a detector? I. Surface area of the detector II. Speed of the source of sound III. Distance from source to detector
II only This question requires application of the Doppler effect: the idea that the speed of both the source and detector of a wave will influence the perceived frequency of that wave. If fine-tuning f that frequency is required, experimenters can change the detected frequency by moving the source at some constant velocity. The surface area of the detector and its distance from the source will only affect the intensity of the wave experienced by that detector.
Describe the stratum spinosum
IN the stratum spinosum, keratinocyte cells become connected to each other; this layer is also the site of Langerhans cells.
How do you calculate the IQR?
IQR = Q3 - Q1
What happens in a slit diffraction with lens
If a lens is placed between a narrow slit and a screen, a pattern is observed consisting of a bright central fringe with alternating dark and bright fringes on each side. The central bright fringe (maximum) is twice as wide as the bright fringes on the sides, and as the slit becomes narrower, the central maximum becomes wider.
What does it mean in terms of energy and calories if a molecule cannot be metabolized?
If a molecule is not metabolized, it can provide no energy and thus no calories.
If air resistance is negligible how does the amount of time it takes an object to ascend and descend compare?
If air resistance is negligible, the amount of time that an object takes to get to its maximum height is the same it takes for it to fall back to its starting height --multiply the value by 2 to get total time.
How do ite/ate and -ous/-ic compare?
If an anion ends in -ite (less oxygen), then the acid will end with -ous acid. If the anion ends in -ate (more oxygen), then the acid will end with -ic acid. Prefixes in the names of the anions are retained. For example: Hypochlorite --> Hypochlorous acid Chlorite --> Chlorous acid Chlorate --> Chloric acid Perchlorate ---> Perchloric acid
How do we select a correct indicator?
If an indicator is chosen correctly and the titration is performed well, the volume difference between the endpoint and the equivalence point is negligible and may be corrected for or simply ignored. Thus, any question involving an ideal indicator will require one to know what the pH of the reaction at the equivalence point will be, whether graphically or mathematically. Once that is determined, select the indicator that has the closest pKa value to it.
What is an easy way to tell if something is an oxidizing agent?
If it contains an O (except for CO) it is an oxidizing agent! (CO is a reducing agent) *PCC and halogens are also oxidizing agents
How do gaseous molecules follow Le Chatelier's principle in regards to changes in volume and pressure? (water and solids are incompressible so this doesn't pertain to them)
If one increases the pressure of a system, it will respond by decreasing the total number of gas moles, thereby decreasing the pressure (note that this scenario assumes that the volume of the system was decreased and then held constant while the system returned to its equilibrium state). When one expands the volume of a system, the total pressure and the partial pressures decrease. The system is no longer in its equilibrium state and will react in the direction of the side with the greater number of moles of gas to restore pressure. Consider the following reaction: N2(g) + 3H2(g)↔2NH3(g) The left side of the reaction has a total number of 4 moles of gas molecules while the right side only has two moles. When the pressure of this system is increased, the system will react in the direction that produces fewer moles of gas. In this case, the direction is to the right, and more ammonia will form. However, if the pressure is decreased, the system will react in the direction that produces more moles of gas; thus, the reverse reaction will be favored, and more nitrogen and hydrogen gas will reform.
How can the standard deviation be used to determine an outlier?
If the data point falls more than three standard deviations from the mean, it is considered an outlier.
Describe the SN1 mechanism
If we start an SN1 reaction with an enantiomerically pure product (that is one enantiomer), the reaction tends to result in a mixture of products where the stereochemistry is the same as the starting material (retention) or opposite (inversion). In other words, some degree of racemization will take place. In this reaction, we find that tertiary alkyl halides react faster than secondary while primary may not happen at all (will go through SN2 instead). This is likely due to the fact that SN1 reactions are done "stepwise" which causes the formation of a carbocation--the formation of the carbocation is the rate-determining step: the leaving group leaves, forming a carbocation, and then the nucleophile attacks the carbocation to give the substitution product. Due to the formation of a carbocation the nucleophile can attack either the back (inversion) or front (retention) of the molecule. Note: the tertiary substitutions happen more quickly because tertiary carbocations are the most stable -- any factor that stabilizes the carbocation, increases the rate at which the leaving group can leave.
Describe flow rate in terms of cross-sectional area and linear speed? What is the formula for their relationship and what is that formula called?
If x liters of fluid pass a point in a given amount of time, then x liters of fluid must pass all other points in the system in the same amount of time. Thus, the flow rate is constant for a closed system and is independent of changes in cross sectional area. However, while the flow rate is constant, the linear speed of the fluid does change relative to cross-sectional area. Linear Speed is a measure of the linear displacement of fluid particles in a given amount of time. The continuity equation: Q= v1A1 = v2A2
Describe circularly polarized light
In circularly polarized light, all of the light rays have electric fields with equal intensity (uniform amplitude) but constantly rotating direction which causes a helical orientation in the propagating wave. Circularly polarized light is created by exposing unpolarized light to special pigments or filters.
What is the formula for Total Mechanical Energy?
TME= UE+ KE= E *where E is total mechanical energy
Describe a fischer-projection
In Fischer projections, horizontal lines indicate bonds that project out from the plane of the page (wedges) whereas vertical lines indicate bonds going into the plane of the page (dashes).
What is the equivalence point?
In acid-base titration it is the point at which the number of acid equivalents present in the original solution equals the number of base equivalents, or vice versa. Note: while a strong acid/strong base titration will have its equivalence point at a pH of 7, the equivalence point does not always occur at pH 7.
Describe secretion in regards to the kidneys
In addition to filtering the blood, the nephrons are able to secrete salts, acids, bases, and urea directly into the tubule by either active or passive transport. Secretion is the movement of solutes from blood to filtrate anywhere besides Bowman's capsule. The quantity and identity of the substances secreted into the nephron are directly related to the needs of the body at that time
How does the acidity of dicarboxylic acids compare to that of monocarboxylic acids?
In dicarboxylic acids, each -COOH group influences the other -COOH group. Carboxylic acids are EWG due to the electronegative oxygen atoms they contain. The net result is that dicarboxylic acids are more acidic than the analogous monocarboxylic acids. However, when one proton is removed from the molecule, the carboxylate anion is formed, resulting in an immediate decrease in the acidity of the remaining carboxylic acid. This makes sense because if the second group were deprotonated it would create a doubly charged species with two negative charges repelling each other. Due to this instability, the second proton is actually LESS acidic (harder to remove) than the analogous proton of monocarboxylic acid.
What's different about the exponents in equilibrium expressions and those in rate laws?
In equilibrium expressions, the exponents are equal to the coefficients in the balanced equation. In rate laws, the exponents must be determined experimentally and often do not equal the stoichiometric coefficients.
How does adding or removing a resistor change the total resistance of a circuit with resistors in series? In parallel?
In series, adding a resistor increases resistance while removing one lowers resistance. In parallel, adding a resistor decreases resistance while removing one will increase it.
Describe the stratum granulosum
In the stratum granulosum, keratinocytes die and lose their nucleus
What is one way in which solubility of a compound can be increased?
Solubility of solids can be increased by increasing temperature. Solubility of gases can be increased by increasing temperature or increasing the partial pressure of the gas above the solvent (Henry's Law).
Describe indicators in titrations
Indicators are weak acids or bases taht have different colors in the ir protonated and deprotonated states. The indicator must be a weaker acid or base than the acid or base being titrated; otherwise the indicator will be titrated first. The point at which the indicator changes to its final color is not the equivalence point but rather the end point.
What is the assumption made about ideal gases?
Individual molecular volume and intermolecular forces are negligible.
What is a statistic?
Information about a sample
What is a parameter?
Information that is calculated using ever person in a population
What is the difference between internal validity and external validity?
Internal validity is the tendency of the same experiment to produce the same results when repeated and provides support for causality. External validity is the ability to take the information generated during research and apply it to a larger group. External validity is also called generalizability.
What happens if you protonate a molecule in a reaction?
It becomes a better leaving group
How do open pipes and strings compare?
Just like strings they can form standing waves. The only difference is that while the string will have two nodes at its ends, the open pipe will have two antinodes at its ends. Thus to determine the harmonic of a string you count the antinodes, but to determine the harmonic of an open pipe you count the antinodes.
What is the formula for Kinetic activity of a gas particle?
KE= 3/2 kB T *where kB is the Boltzmann constant
What is the formula for kinetic energy?
KE= ½ mv²
What is Km?
KM is the concentration of substrate at which the kinetics experiment reaches half the maximum velocity
What is the formula for Kcat?
Kcat= Vmax/[E]total
What is the equilibrium constant formula for water?
Kw = [H₃O+][OH-] = 1E-14 Note: each mole of water that autoionizes produces one mole each of hydrogen (or hydronium) ions and hydroxide ions, so the concentrations of the hydrogen ions and hydroxide ions are always equal in pure water at equilibrium. Thus, the concentration of each of the ions in pure water at equilibrium at 298 K is 10^-7 M. However, the concentrations will not always be equal. In fact, they will only be equal when the solution is neutral. --Nevertheless the product will ALWAYS be 1E-14 when he temperature is 298K.
What are Langerhans cells?
Langerhans cells are special macrophages that reside within the stratum spinosum. These cells are capable of presenting antigens to T-cells in order to activate the immune system.
What is the difference between oxidation number and formal charge>
Oxidation number assumes unequal division of electrons in a bond, "awarding" the electrons to the more electronegative element. Formal charge, on the other hand, assumes equal division of electrons in bonds, "awarding" one electron to each atom in the bond. In reality, the distribution of electron density lies somewhere between these two extremes.
On a globular protein, what are the preferred locations for leucine and phenylalanine residues?
Leucine and phenylalanine both prefer the interior: leucine and phenylalanine have hydrophobic side chains and thus prefer to be buried on the interior.
Describe melanocytes
Melanocytes are a cell type derived from neural crest cells and found in the stratum basale. The cells produce melanin, a pigment that serves to protect the skin from DNA damage caused by ultraviolet radiation. One produced, the pigment is transferred to keratinocytes.
Write the Clausius-Clapeyron equation
Ln (P/P0)= (∆Hvap/R)((1/T₀)-(1/TB)) *where TB is the boiling point at the pressure of interest
Do peptide bonds have high or low reactivity?
Low Peptide bonds are very stable under physiological conditions, which explains the choice of protein as a cellular scaffold.
Is it easier to boil fluid in high pressure or low pressure?
Low pressure, like in the mountains (there's less pressure on the surface of the fluid forcing the molecules down)
What is the IR absorption frequency for a N-H?
N-H bonds are in the same region as O-H bonds (around 3300 cm^-1) but have a sharp peak instead of a broad one
What is the formula for molarity?
M = moles of solute/liters of solution
How do we do multiplication and division with significant figures?
Maintain as many digits as possible throughout the calculations so that there is very little rounding error, then round to the number of significant digits that is the same as the least number of significant digits in any of the factors, divisors, or dividends
Describe the hybridization of octahedral compounds
Octahedral compounds have six σ bonds and no lone pairs. According to valence bond theory, the central atom requires the hybridization of six atomic orbitals, d2sp3.
how to name molecules with two oxyanions
Many polyatomic anions contain oxygen and are therefore called oxyanions. When an element form two oxyanions the name of the one with less oxygen ends in -ite and the one with more oxygen ends in -ate. Ex:) NO2- nitrite vs NO3- nitrate SO32- sulfite vs SO42- sulfate *The "litest" anions have the fewest oxygens; the heaviest anions ate the most oxygens.
What is mechanical advantage? How is it calcilated?
Mechanical advantage is the ratio of magnitudes of the force exerted on an object by a simple machine (Fout) to the force actually applied on the simple machine (Fin). It is calculated by: M.A. = Fout/Fin This tells is the factor by which a simple machine multiplies the input force to accomplish work.
What is the formula for dilution?
MiVi=MfVf
What is a mixed-order reaction?
Mixed order reactions sometiems refer to non-integer orders (fractions) an din other cases to reactions with rate orders that vary over the course of the reaction. Fractions are more specifically described as broken order. In recent times, the term mixed order has come to refer soley to reactions that change order over time.
Describe the structure of NAD
NAD is composed of two nucleotides joined by their phosphate groups
describe NMR spectroscopy
NMR spectroscopy is based on the fact that certain atomic nuclei have magnetic moments that are oriented at random. When such nuclei are placed in a magnetic field, their magnetic moments tend to align either with or against the direction of this applied field. Nuclei with magnetic moments that are aligned with the field are said to be in the alpha-state (lower energy). The nuclei can then be irridated with radiofrequency pulses that match the energy gap between the two states, which will excite some lower- energy nuclei into the beta-state (higher energy). The absorption of this radiation leads to excitation at different frequencies, depending on an atom's magnetic environment. In addition, the nuclear magnetic moments of atoms are affected by nearby atoms that also possess magnetic movements.
Describe NaBH4
NaBH4 is a gentle reducing agent that is NOT strong enough to reduce carboxylic acids.
What is the equivalence point equation?
NaVa = NbVb *where Na and Nb are the acid and base normalities, respectively, and Va and Vb are the volumes of acid and base solutions, respectively.
What is a negative control?
Negative controls ensure no change in the dependent variable when no change is expected. For example, administering an HIV assay to a group of cells known not to be infected with HIV would be a negative control.
What is an imine and how is it formed?
Nitrogen and nitrogen-based functional groups act as good nucleophiles due to the lone pair of electrons on nitrogen and react readily with the electrophilic carbonyls of aldehydes and ketones. In the simplest case, ammonia adds to the carbon atom, and water is lost, producing an imine, a compound with a nitrogen atom double-bonded to carbon atom. Note: Because a small molecule is lost during the formation of a bond between two molecules, this is an example of a condensation reaction. Because nitrogen replaces the carbonyl oxygen, this is also an example of a nucleophilic substitution.
If we want to label a molecule with radioactive tritium (3H), and we are using water as a solvent, should we pick a site on the molecule that can do hydrogen bonding?
No, because then the 3H could be lost to water instead of found on the molecule
Is hydroxide a good leaving group?
No, we want t protonate it into water to make it a better one
How does distance affect non-conservative forces?
Non-conservative forces unlike conservative forces are path dependent. So the longer the distance traveled, the larger the amount of energy dissipated.
What is normality?
Normality (N) is a measure of concentration given in the units equivalents/L.
What is nuclear binding energy?
Nuclear binding energy is the amount of energy that is released when nucleons (proton and neutrons) bind together. The more binding energy per nucleon released, the more stable the nucleus. The four fundamental forces of nature are the strong and weak nuclear force, which contribute to the stability of the nucleus, electrostatic forces, and gravitation. Note: the binding energy per nucleon peaks at the element iron, which implies that iron contains the most stable nucleus. In general, intermediate-sized nuclei are more stable than very large or small nuclei.
Briefly describe the mechanism, of nucleophilic substitution reactions
Nucleophilic acyl substitution is the substitution of an attacking nucleophile for the leaving group of an acyl compounds which includes carboxylic acids, amides, esters, and anhydrides. The nucleophile attacks, opening the carbonyl and forming a tetrahedral intermediate. The carbonyl then reforms, kicking off the leaving group. This reaction is favored by acidic or basic conditions.
Which has a higher electronegativity Cl or O?
O; we increase going to the right but increase more going up
Describe open systems
Open systems can exchange both matter and energy with the environment. In an open system, not only does the matter carry energy, but more may be transferred in the form of heat or work. For example, boiling a pot of water or humans
Describe Bernouilli's Equation
P1 + ρgh1 + 1/2ρv1^2 = P2 + ρgh2 + 1/2ρv(2)^2 *h is the average height of the fluid (or tube above some datum) This equation states that the sum of the static pressure and the dynamic pressure will be constant within a closed container for an incompressible fluid not experiencing viscous drag. It is essentially a statement of energy conservation more energy dedicated toward fluid movement means less energy dedicated toward static fluid pressure, and vice versa.
What is the formula for calculating the power of a resistor?
P= IV= I²R = V²/R This tells us the rate at which energy is dissipated by a resistor
If you have multiple lenses in contact, how do you calculate the power?
P= P1+P2+P3+P4+....+Pn
What is the formula for pressure
P=F/A This is calculated in pascals (the SI unit) which is equivalent to N/m². Thus if a pressure unit is given in something other than Pa, we have to covert it
Write the cell diagram for the discharging state of a lead acid battery.
Pb (s) | H2SO4 (4M) || H2SO4 (4M) | PbO2(s)
A chemist wishing to activate a carboxyl group could effectively do so by: A. Reacting it with SOCl2 B. heating the solution C. Adding aqueous base D. adding excess alcohol and HCl.
Peptide bonds form by the nucleophilic attack of the amino group of an amino acid on the carboxyl group of another. The reaction of thionyl chloride with a carboxylic acid substitutes a chlorine atom for the carboxyl hydroxyl group, producing an acyl chloride. An acyl chloride is the most reactive of the various kinds of carboxylic acid derivatives, and certainly more so than the corresponding carboxylic acid. This is because the chloride ion is a much better leaving group than the hydroxide anion and is therefore more easily displaced by the nucleophilic attack of the amino group.
How is a second-order rate law plotted?
Plotting a reaction that is second-order with respect to a single reactant on a concentration vs time curve results in a nonlinear graph. This curve shows that the rate of formation of product is dependent on the concentration of reactant. Plotting 1/ [A] vs time reveals a linear curve; the slope of such a curve is equal to the rate constant, k
What are physical properties
Physical properties are characteristics of processes that don't change the composition of matter, such as melting point, boiling point, solubility, odor, color, and density.
Describe plane mirrors
Plane mirrors, being flat reflective surfaces, cause neither convergence nor divergence of reflected light rays. Because the light does not converge at all, plane mirrors always create virtual images. In a plane mirror, the image appears to be the same distance behind the mirror as the object is in front of it. In other words, plane mirrors create the appearance of light rays originating behind the mirrored surface. Because the reflected light remains in front of the mirror but the image appears behind the mirror, the image is virtual.
How does the application of a polarized filter impact the wavelength of light passing through the filter?
Plane polarization ahs no effect on the wavelength (or frequency or speed) of light. Polarization does affect the amount of light passing through a medium and light intensity.
Describe plane polarized light
Plane polarized light (or linearly polarized light) is light in which the electric fields of all the waves are oriented in the same direction (that is, their electric field vectors are parallel). It flows that their magnetic field vectors are also parallel, but convention dictates that the plane of the electric field identifies the plane of polarization. Unpolarized light has a random orientation of its electric field vectors: sunlight and light emitted from a light bulb are prime examples. Note: Plane polarized light is created by passing unpolarized light through a polarizer.
How is a first-order rate law plotted?
Plotting a first-order reaction on a concentration vs time curve results in a nonlinear graph. This curve shoes that the rate of formation of product is dependent on the concentration of reactant. Plotting ln [A] vs time reveals a straight line; the slope of such a line is the opposite of the rate constant, k.
How do you use the right-hand rule to determine the direction of a magnetic field around a wire?
Point your thumb in the direction of the current and wrap your fingers around the current-carrying wire. Your fingers then mimic the circular field lines, circling around the wire.
How to name polyatomic anions containing hydrogen
Polyatomic anions often gain one or more H+ ions to form anions of lower charge. The resulting ions are named by adding the word hydrogen or dihydrogen to the front of the anion's name. An older method uses the prefix bi- to indicate the addition of a single hydrogen atom. Ex:) HCO3- --> hydrogen carbonate or bicarbonate HSO4- --> hydrogen sulfate or bisulfate H2PO4- --> dihydrogen phosphate
What does a positive change in potential energy, heat, and work mean? What about negative?
Positive: A positive change in potential energy means that temperature of the system is increasing. A positive heat value means that heat is flowing into the system. A positive work value means that work is being done by the system (expansion). Negative: A negative change in potential energy means that temperature of the system is decreasing. A negative heat value means that heat is flowing out of the system. A negative work value means that work is being done on the system (compression).
Describe KMnO4
Potassium permanganate is a very strong oxidizing agent. It will oxidize primary alcohols and aldehydes to carboxylic acids, secondary alcohols to ketones, form diols from alkenes, and oxidatively cleave carbon-carbon multiple bonds.
What is the formula for the power of a lens?
Power (Dioptres, D) = 1/Focal length (m) Note: P has the same sign as f and is therefore positive for a converging lens and negative for a diverging lens
What is power? How is it calculated?
Power refers to the rate at which energy is transformed from one system to another. It is calculated by the equation: P= W/t = ∆E/t
What is the Cahn Ingold Prelog priority rule?
Priority is assigned based on the atom bonded to the double-bonded carbons: the higher the atomic number, the higher the priority. If the atomic numbers are equal, priority is determined by the next atoms outward: again, whichever group contains the atom with the highest atomic number is given top priority.
What is systemic desensitization?
Systemic desensitization is the use of increasingly proximal stimuli to gradually reduce the fear response in an individual. Since the amygdala is the brain structure that is more responsible for the fear response, its function would be diminished when exposed to the stimulus in question.
What is Poiseuille's Law?
Q = (pi*r^4*changeP)/ (8*viscosity*L) *Q= flow rate
What is the formula for the reaction quotient?
Qc = [C]^c[D]^d / [A]^a[B]^b *remember that only species in solution are included
What are scalars?
Quantities that only have a magnitude; no direction Ex: distance, speed, energy, pressure, and mass
Describe quinones
Quinones are not necessarily aromatic because they lack the classic aromatic conjugated ring structure. Some quinones do have an aromatic ring, but this is not always the case. Quinones serve as electron acceptors biochemically, specifically in the electron transport chain in both photosynthesis and aerobic respiration.
What is the formula for resistance?
R= (rho* L)/ A *where rho is the resistivity, L is the length of the resistor, and A is its cross-sectional area.
Gringard Reagent
RMgX Uses a nucleophilic attack to make more carbon-carbon bonds
What are the length of the waves from longest to shortest (low frequency to high frequency)?
Radio waves, microwaves, infrared light, visible light, ultraviolet light, x-rays, and gamma rays: Raging Martians Invaded Venus Using X-ray Guns
What is Raoult's Law?
Raoult's law states that ideal solution behavior is observed when solute-solute, solvent-solvent, and solute-solvent interactions are all very similar.
Compare kinetic and thermal control of reactions
Reactions may have both kinetic and thermodynamic products that can be regulated by temperature and the presence of a catalyst. Kinetic Products are higher in free energy than thermodynamic products and can form at lower temperatures. These are sometimes termed "fast" products because they can form more quickly under such conditions. Thermodynamic Products are lower in free energy than kinetic products and are therefore more stable. Despite proceeding more slowly than the kinetic pathway, the thermodynamic pathway is more spontaneous (more negative ∆G).
When do real gases deviate from ideal behavior? How?
Real gases deviate from ideal behavior under high pressure (low volume) and low temperature conditions: At moderately high pressures, low volumes, or low temperatures , real gases will occupy less volume than predicted by the ideal gas law because the particles have intermolecular attractions (this is negligible in ideal gases but not real gases). At extremely high pressures, low volumes, or low temperatures, real gases will occupy more volume tan predicted by the ideal gas law because the particles occupy physical space --while the ideal gas law assumes that a gas can be compressed to take up zero volume, this is not actually physically possible, gas particles themselves take up space.
How do you break disulfide bonds?
Reduce them! dump electrons on them. This would happen in the cytosol since it is a REDUCING environment.
What is the formula for standard deviation?
SD=sqrt(Σ(x-xbar)^2)/(n-1))
How is the Rf value calculated?
Rf= Distance travelled by sample spot/Distance travelled by solvent spot
Describe rotational equilibrium
Rotational equilibrium exists when the vector sum of all the torques acting on an object is zero. This is called the second condition of equilibrium.
What is rotational motion?
Rotational motion occurs when forces are applied against an object in such a way as to cause the object to rotate around a fixed pivot point, also known as the fulcrum. Application of force at some distance between the fulcrum generates torque (T) or the moment of force. The distance between the applied force and the fulcrum is termed the lever arm. It is the torque that generates rotational motion, not the mere application of the force itself. This is because torque depends not only on the magnitude of the force but also on the length of the lever arm and the angle at which the force is applied. The equation for torque is a cross product: T= r * F = rFsinθ *where are is the length of the lever arm and
What amino acids can be phosphorylated?
Ser, Thr, Tyr S T Y They are phosphorylated on their hydroxyl side chains. This is used for enzyme activation/inactivation
What are the polar amino acids?
Serine (S), Threonine (T) Cysteine(C), Tyrosine (Y), Asparagine (N), Glutamine (Q) Stop Talking, Call Your New Queen
Assume the likelihood of having a male child is equal to the likelihood of having a female child. In a series of ten live births, the probability of having at least one boy is?
Simplify this question by recording it as the probability of not having all girls. Having at least one boy and having all girls are mutually exclusive events, and no other possibilities can occur. Thus, the probability of having all girls is (0.5)^10 and the probability of having at least one boy is 1- (0.5)^10, or 99.90%
How do you calculate the tension of two ropes holding a block?
T1 + T1 = mg
What is the center of curvature?
The point in the center of the sphere from which the mirror was sliced. Thus, the center of curvature is in front of a concave mirror but behind a convex mirror.
In magnetic resonance imaging (MRI), hydrogens in tissues are subjected to a magnetic field. In response, the protons emit radio frequency radiation, which is imaged as a bright area. Which of the following tissues is LEAST likely to show up as bright region in an MRI scan? A. Kidney B. Eyes C. Femur D. Biceps
Since, as stated in the question stem, MRI relies on the imaging of protons, and the brightness is proportional to the number of protons, this question is really asking which tissue is likely to not have very many protons. That is, since most of the photons in biological tissues are found in water, the question is really "which of the following tissues had the lowest water content?" Soft tissues like internal organs (for example, the kidney), eyes, and muscles (like the biceps) will have a higher water content than bones like the femur.
What is the difference between sin and cosine in going from 0 degrees to 90 degrees?
Sine increases going from 0 to 90 while cosine decreases.
In what segments of the nephron is sodium actively transported out of the nephron?
Sodium is actively transported out of the nephron in the proximal and distal convoluted tubules where the concentration of sodium outside of the nephron is higher than inside this, energy is required to transport the sodium molecules against their concentration gradient. In the inner medulla, however, sodium and other ions diffuse passively down their concentration gradients at the thin ascending limb of the loop of Henle. The thick ascending limb of the loop of Henle is thick because its cells contain mainly mitochondria -- which produce the ATP needed for active transport of sodium and chloride out of the filtrate.
Which of the following properties of a 2.3 MHz ultrasound wave remains unchanged as it passes into human tissues? A. Frequency B. Wave speed C. Amplitude D. Wavelength
Solution: The correct answer is A. The answer to this question is A because the frequency of a wave is not affected by the medium through which it propagates.
Describe resistivity
Some materials are intrinsically better conductors of electricity than others. For example, copper conducts electricity better than plastic, which is why electrical wires have a copper core surrounded by a layer of plastic rather than the other way around. The number that characterizes the intrinsic resistance to current flow in a material is called the resistivity (rho), for which the SI unit is the ohm-meter.
What is the difference between specific heat and heat capacity?
Specific heat (c) is the energy required to raise the temperature of one gram of a substance by one degree Celsius. Heat capacity (mc) is the product of mass and specific heat and is the energy required to raise any given amount of a substance one degree Celsius.
What is spherical aberration?
Spherical aberration is a blurring of the periphery of an image as a result of inadequate reflection of parallel beams at the edge of a mirror or inadequate refraction of parallel beams at the ends of a lens. This creates an area of multiple images with very slightly different image distances at the edge of the image which appears blurry. This is a result of an imperfection in the optical system.
What is the difference between standard conditions and STP?
Standard conditions are used for kinetics, equilibrium, and thermodynamics problems; STP is used for ideal gas calculations.
What are state functions?
State functions are thermodynamic properties that are a function of only the current equilibrium state of a system. In other words, state functions are defined by the fact that they are independent of the path taken to get to a particular equilibrium state. The state functions include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy. On the other hand, process functions, such as work and heat, describe the path taken to get from one state to another.
What is the second law of thermodynamics?
Statistically speaking, energy flows from hot to cold until both objects reach equlibrium
What are the steps for balancing a redox reaction? Balance MNO₄- + I- → I₂ +Mn₂+
Step 1: Separate the two half reactions. Step 2: Balance the atoms of each half-reaction. First, balance all atoms except H and P. Next, in an acidic solution, add H2O to balance the O atoms and then add H+ to balance the H atoms. In a basic solution use OH_ and H2O to balance the O and H atoms. Step 3: Balance the charges of each half-rection. Add electrons as necessary to one side of the reaction so that the charges are equal on both sides. Step 4: Both half-reactions must have the same number of electrons so that they cancel each other out in the next step. IN this example, you need to multiply the oxidation half-reaction by 5 and the reduction half-reaction by 2. Step 5: Add the half-reactions, canceling out terms that appear on both sides of the reaction arrow. Step 6: Confirm that mass and charge are balanced. There is a +4 net charge on each side of the reaction equation, and the atoms are stoichiometrically balanced. 2MNO₄- + 16 H+ + 10I- → 5I₂ + 2Mn₂++ 8 H2O
What's the difference between stereoisomers and structural (constitutional) isomers?
Stereoisomers have the same connectivity while structural (constitutional) isomers do not
Is NaOH a weak or strong base?
Strong
Describe strong acids and bases
Strong acids and bases completely dissociate into their component ions in aqueous solutions. For example, when sodium hydroxide is added to water, the ionic compound dissociates according to the net ionic equation: NaOH(s) -> Na+(aq) + OH- 9aq) Hence, in a 1 M NaOH solution, complete dissociation yields 1 M Na+ and 1 M OH-.
Describe the strong nuclear force
Strong nuclear force is one of the four primary forces and provides the adhesive force between nucleons (protons and neutrons_ with the nucleus.
What property or properties do structural isomers have in common?
Structural isomers share a molecular formula, and not necessarily anything else.
Describe the setup for NMR
TMS is used as the control and is located at 0ppm . You do NOT count this peak when determining the structure of a molecule. As you move to the left of TMS, the frequency shift increases and you are moving downfield. If an EWG is near the hydrogen, it will deshield the hydrogen and pull its NMR peak downfield. If an EDG is added, it will shield the proton and pull its NMR peak upfield. The height of the peaks represent the ratio of hydrogens that have the same magnetic quality on a methyl group. For example CH3 would be one tall peak and HOCl2 would have one shorter peak at a ratio of 3:1. IF there are two protons in close proximity that are not magnetically identical, spin-spin coupling (splitting) occurs.
What is the difference between heat and temperature?
Temperature is an indirect measure of the thermal content of a system that looks at the average kinetic energy of particles in a sample. Heat is the thermal energy transferred between objects as a result of differences in their temperatures. the most we can say about temperature is that when a substance's thermal energy increases, its temperature also increases. Nevertheless, we cannot say that something that is hot necessarily has greater thermal energy (in absolute terms) than a substance that is cold. For example, we might determine that a large amount of lukewarm water has a greater total heat content than a very small amount of hot water.
What determines electrolytic conductivity?
The strength of a solution. Distilled deionized water has such a low ion concentration that it may be considered an insulator, while sea water and orange juice are excellent conductors.
Absorption of ultraviolet light by organic molecules always results in what process?
The absorption of ultraviolet light by organic molecules ALWAYS results in electronic excitation --the excitation of bound electrons
What elements are found in nature only in their charged states?
The alkali metals (Group IA or Group I) and the alkaline metals (Group IIA or Group 2), which have charges of +1 and +2, respectively, in the natural state.
What does R33G mean?
The arginine in the 33rd position is replaced with glycine
What keeps chair conformations stable as far as bonded groups?
The bulkiest group will favor the equitorial position to reduce nonbonded strain (flagpole interactions). In rings with more than one substituent, the preferred chair form is determined by the larger group, which will prefer the equatorial position.
How do we calculate the heat released by a bomb calorimeter?
The calorimeter is a closed system, so no heat leaves the system and qr= qw + qb
What is normal force?
The component of force between two objects in contact that is perpendicular to the plane of contact between the object and the surface on which it rests: "N"
What is true about circuits in series?
The current is the same throughout
How does a change in electric potential energy from -4J to -7J reflect on the stability of a system?
The decrease in potential energy indicates that the system has become more stable
What is gauge pressure? How is it calculated?
The difference between in absolute (aka hydrostatic) pressure and atmospheric pressure. Pgauge= Ptotal-Patm = (P0+ rho(g)h)-Patm In liquids, gauge pressure is caused by the weight of the liquid above the point of measurement. *Pt is the absolute pressure *P₀ is the incident or ambient pressure (the pressure at the surface) *rho is the density of the fluid not the object Note: When P0=Patm, then Pgague simply = rho*g*z
In an experiment to determine the efficiency of a new assistive device for seniors, a kinesiologist sets up an experiment with several weights and pulleys. When he calibrates the scale it registers each weight as three kilograms greater than it actually is. What impact does this have on the experiment? A. The efficiency will be most skewed for the smallest weights B. The efficiency will be skewed equally for all weights C. The efficiency will be least skewed for the smallest weights D. The constant difference will not skew efficiency measures
The efficiency will be most skewed for the smallest weights. Since efficiency = (load * load distance)/ (effort * effort distance), if the weights (load) were erroneously high but the effort was measured accurately, efficiency measures will be erroneously calculated as higher than actual efficiency. Since efficiency is directly proportional to load, error in efficiency (%) is directly proportional to error in load (%). The error in load (%) = absolute error/ actual load. As the actual load decreases, the percent error increases.
What is the "effort"?
The effort is the input force of a simple machine, which acts over a given effort distance to determine the work input of the simple machine
Compare filtrate to blood
The filtrate is similar in composition to blood but does not contain cells or proteins due to the filter's ability to select based on size. The filtrate is isotonic to blood so that neither the capsule nor the capillaries swell.
What would happen if a person who weighed 170 lbs stepped onto a scale that was precise but not accurate?
They may get readings between 129 and 131, a relatively narrow range.
Describe the acidity of carboxylic acids
The hydroxyl hydrogen of a carboxylic acid is quite acidic. This results in a negative charge that remains after the hydrogen is removed and resonance stabilization occurs between both of the electronegative oxygen atoms. Delocalization of the negative charge results in a very stable carboxylate anion. The more stable the conjugate base is, the easier it is for the proton to leave, and thus, the stronger the acid.
What happens when a battery, resistor, and capacitor are in series?
The initial voltage on the capacitor is zero and as charge accumulates, the voltage rises towards the voltage of the battery --the rise is asymptotic
What is effusion?
The flow of gas particles under pressure from one compartment to another through a small opening.
Dynamic pressure
The force exerted by a fluid in motion Dynamic pressure = 1/2 rho * v^2
What are the requirements for a hydrogen bond?
The formation of a hydrogen bond requires both a hydrogen bond donor (a molecule with a hydrogen bonded to a highly electronegative atom such as oxygen or nitrogen) and a hydrogen acceptor (an electronegative atom (such as O or N) with an available lone pair of electrons.
What does it mean if Q < Keq?
The forward reaction ahs not yet reached equilibrium. There is a grater concentration of reactants (and smaller concentration of products) than equilibrium. The forward rate of reaction is increased to restore equilibrium.
What does it mean if Q > keq?
The forward reaction has exceeded equilibrium. There is a greater concentration of products ( and smaller concentration of reactants) than equilibrium. The reverse rate of reaction is increased to restore equilibrium.
What is static friction?
The friction that exists between a stationary object and the surface on which it's resting: fs.
What is true about oxyanions that contain halogens? Like ClO-?
The halogen is assigned a positive oxidation state
What is enthalpy?
The heat content of a system at constant pressure. THIS IS ONLY WHEN THE SYSTEM IS UNDER CONSTANT PRESSURE
Describe the blood supply to the kidneys
The kidney has one of the few portal systems in the body. A portal system consists of two capillary beds in series through which blood must travel before returning to the heart. The renal artery branches out, passes through the medulla, and enters the cortex as afferent arterioles. The highly convoluted capillary tufts derived from these afferent arterioles are known as glomeruli. After blood passes through a glomerulus. the efferent arterioles then form a second capillary bed. The capillaries surround the loop of Henle and are known as vasa recta.
What is type 1 error?
The likelihood that we report a difference between two populations when one does not actually exist, we incorrectly reject the null hypothesis. This is a false positive --an innocent man goes to jail
What is the "load"?
The load is the output force of a simple machine which acts over a given load distance to determine the wok output of the simple machine
What is the fundamental frequency?
The lowest frequency of a standing wave that can be supported in a given length of string. The first harmonic.
What would happen if a person who weighed 170 lbs stepped onto a scale that was accurate but not precise?
They may get readings between 150 and 190 pounds.
Describe the mass defect
The mass defect is the difference between the mass of the unbonded nucleons and the mass of the bonded nucleons. The unbonded nucleons have more energy and therefore more mass than the bonded constituents. The mass defect is the amount of mass converted to energy during nuclear fusion.
What is the amplitude of a wave?
The maximum displacement from the equilibrium position to the top of a crest or the bottom of a trough
What value can be disrupted by an outlier?
The mean; when this happens, the mean may not be an appropriate measure for the data
What is a median?
The median value for a set of data is its midpoint., where half of the data points are greater than the value and half are smaller.
What is the threshold frequency?
The minimum frequency of light that causes the ejection of electrons, fT. The threshold frequency depends on the type of metal being exposed to radiation.
Describe the stratum corneum
The most superficial layer of skin, the stratum corneum contains up to several dozen layers of flattened keratinocytes, forming a barrier that prevents invasion by pathogens and that helps to prevent loss of fluids and salt.
How do you determine whether or not an element can be reduced?
The oxidation states in the molecule are found by subtracting their assigned electrons from their periodic group number
Why is carbonyl carbon an electrophile?
The oxigen is more electronegative and pulls electrons away from teh carbon, makig the carbon electrophillic and a ggod target for neutrophiles
Why are phenols typically stronger acids than simple alcohols?
The oxygen-containing anion is resonance-stabilized by the ring
isoelectric point
The pH value at which the amino acid exists as a zwitterion
What is a "period" and how is it calculated?
The period (T) of a wave is the number of seconds it takes to complete a cycle. It is calculated by : T= 1/f
What is vapor presssure?
The pressure exerted by evaporated particles above the surface of a liquid.
In statistics what is alpha?
The probability of making a type I error: a false positive. Alphas are so cocky they say things are true even when they aren't.
mutarotation
The rapid interconversion between different anomers of a sugar
What is Kcat?
The rate constant of the rate limiting step of a reaction. The rate of the 'choke point' of a reaction sequence is equal to the rate of the reaction overall. kcat is the "turnover number" for an enzyme. It measures the number of substrate molecules turned over (into product) per enzyme molecule, per second.
What is specific gravity? What is the formula for it? What is it used for?
The ratio of the density of a fluid compared with the density of pure water: SG= p/ (1 g/cm3) Can be used to determine if an object will sink or float in water
What is electric potential?
The ratio of the magnitude of a charge's electric potential energy to the magnitude of the charge itself V= U/q so V= kQ/r *the unit is 1 V which equals 1 J/C
Tautomerization
The rearrangement of bonds within a compound, usually by moving a hydrogen and forming a double bond
How does the skin affect osmolarity?
The skin helps to maintain the osmolarity of the body. This is because the skin is relatively impermeable to water. This prevents not only the entrance of water through the skin, but also the loss of water from the tissues. This becomes very important in cases such as burns or large losses of skin as dehydration of the tissues becomes a real threat to survival.
What is solubility?
The solubility of a substance is the maximum amount of that substance that can be dissolved in a particular solvent at a given temperature. When this maximum amount of solute has been added, the dissolved solute is in equilibrium with its undissolved state, and we say that the solution is saturated. If more solute is added, it will not dissolve. but rather remain in a solid form, precipitating to the bottom of the container.
What are the state functions?
The state functions include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy. When I'm under pressure and feeling dense all I want to do is watch TV and get HUGS.
What is hydrostatics?
The study of fluids at rest and the forces and pressures associated with standing fluids
What is absolute zero?
The theoretical temperature at which there is no thermal energy
Describe the keto-enols
The two isomers, which differ in the placement of a proton and the double blond. are called tautomers. The equilibrium between the tautomers lies far to the keto side, so there will be many more keto isomers in solution. The process of interconverting from the keto to the enol tautomer is called enolization, or more generally, tautomerization. By extension, ay aldehyde or ketone with a chiral alpha-carbon will rapidly become a racemic mixture as the keto and enol forms interconvert, a phenomenon known as alpha-racemization.
How can Kw be changed?
The value of Kw, like any other equilibrium constant, is dependent ONLY on temperature. Therefore, isolated changes in concentration, pressure, or volume will not affect Kw, only changes in temperature will.
What are the rays we draw for a convex lens?
There are three: 1. Principal ray: A ray parallel to the axis that refracts through the focal point of the front face of the lens 2. Central ray: a ray that goes through the center of the lens and continues straight through with no refraction 3. Focal ray: A ray that travels through or toward the focal point before reaching the lens, it reflects parallel to the axis
A point mutation occurs, changing the sequence 5'AUGAUCUGUUGCUGAUAG-3' to 5'AUGAUCUGCUGCUGAUAG-3' What is the likely effect on the subsequent polypeptide?
There will be no effect Looking at the sequences, it can be seen that the mutation occurs n the 3rd nucleotide of a codon and it changes a U to a C. Both uracil and cytosine are pyrimidines and there s a wobble in the 3rd nucleotide, which allows the reasonable conclusion that there will not be a change in the amino acid, the primary structure, the secondary structure, or the tertiary structure.
What are neutralization reactions?
These are a specific type of double-displacement reaction in which an acid reacts with a base to produce a salt (and, usually, water). For example, hydrochloric acid and sodium hydroxide will react to form sodium chloride and water.
Describe weak acids and bases
These are acids and bases that only partially dissociate in aqueous solutions. A species is a weak acid if its Ka is <1 and its a weak base if its Kb is <1.
Describe Pacinian corpuscles
These are sensory receptors located in the dermis that respond to deep pressure and vibration
Describe Meissner's corpuscles
These are sensory receptors located in the dermis that respond to light touch
Describe the innervation of sweat glands
They are innervated by postganglionic sympathetic neurons that utilize acetylcholine
Describe diastereomers
They are stereoisomers that are not mirror images. Unlike enantiomers, diastereomers have different chemical properties (however, they might behave similarly in particular reactions because they have the same functional groups) and physical properties from each other.
Describe splitting a vector into components for vector addition
This involves breaking each vector into perpendicular components. In most cases, these components are horizontal and vertical (x- and y- components, respectively ); however in some instances -- such as inclined planes -- it may make more sense to define the components as parallel and perpendicular to some other surface. Given the vector V, we can find the x- and y- components by drawing a right triangle with V as the hypotenuse.
What is chelation?
This occurs in complex ions where the central metal cation is bonded to the same ligand in multiple places. This generally requires large organic ligands that can double back to form a second (or even third) bond with the central cation. Chelation therapy is often us to sequester toxic metals.
Describe the gauche conformation
This occurs when the largest groups of a molecule are 60 degrees apart. Note: gauche means unsophisticated or awkward, the large group is standing awkwardly too close to another group
Describe the eclipsed conformation
This occurs when the largest groups of the molecule are 120 degrees apart and overlap with the hydrogen atoms on the adjacent carbon.
Describe the totally eclipsed conformation
This occurs when the largest groups of the molecule directly overlap each other with 0 degrees separation. This is the molecule's highest energy state. Totally eclipsed molecules are the least favorable energetically because the two largest groups are synperiplanar (in the same plane, on the same side).
Which elements have the same reactivity?
Those in the same group
How many moles of electrons pass through a circuit containing a 100V battery and a 2 ohm resistor over a period of 10 seconds? (Note: F = 9.65E4 C/ mol e- )
To determine the moles of charge that pass through the circuit over a period of 10S, we will have to calculate the amount of charge running through the circuit. Charge is simply current multiplied by time, and the current can be calculated using Ohm's law: V= IR and I=Q/∆t → Q= V∆t / R Q= ((100 V)(10s))/ 2 ohm = 500 C Then, calculate the number of miles of charges that this represents by using Faraday constant and approximating F as 10⁵ C/mole e- 500 C [mol e- / 10⁵ C] = 5E-3 mol e-
How do we determine what type of titration graph we are looking at?
To identify which type of titration is being shown in a graph, identify the starting position in the graph (pH>>7 = titrand is a strong base, >7 (slightly) = weak base, <7 (slightly)= weak acid, <<7 pH = strong acid), and determine where the equivalence point is
Why must the person either lean forward or slide their feet under the chair in order to stand up?
To keep the body in equilibrium while rising As the person is attempting to stand, the only support comes from the feet on the ground. The person is in equilibrium only when the center of mass is directly above their feet. Otherwise, if the person did not lean forward or slide the feet under the chair, the person would fall backward due to the large torque created by the combination of the weight of the body (applied at the person's center of mass) and the distance along the horizontal between the center of mass and the support point.
Describe fractional distillation
To separate two liquids with similar boiling points (less than 25 degrees celsius apart) , we use fractional distillation. In this technique, a fractionation column connects the distillation flask to the condenser. A fractionation column is a column in which the surface area is increased by the inclusion of inert objects like glass beads or steel wool. As the vapor rised up the column, it condenses on these surfaces and refluxes back down until rising heat causes it to evaporate again, only to condense again in the column. Each time the condensate evaporates, the vapor consists of a higher proportion of the compound with the lower boiling point. By the time the top of the column is reached, only the desired product drips down to the receiving flask.
What does the direction of rotation mean as in terms of torque?
Toques that generate clockwise rotation are considered negative , while torques that generate counterclockwise rotation are positive. Thus, in rotational equilibrium, it must be that all of the positive torques exactly cancel out all of the negative torques. Similar to the behavior defined by translational equilibrium, there are two possibilities of motion in the case of rotational equilibrium: Either the object is not rotating at all (that is, it is stationary), or t is rotating with a constant angular velocity. The MCAT almost always takes rotational equilibrium to mean that the object is not rotating at all
A dipole is placed in an electric field and is allowed to come to equilibrium. How would the dipole react if the direction of the electric field is suddenly reversed?
Torque is a function of both force applied and the angle at which it is applied. A dipole placed in an electric field will experience a torque until it comes to rest oriented within the field, at which point the angle between the plane of the dipole and the field is 0degrees. Once this point is reached, inverting the electric field has no impact on the dipole because it will now have an angle of 180 degrees, the sine of which is still 0. Note: however, that this is an unstable setup any deviation in the dipole from its rest position will immediately result in torque on the dipole and force it to realign with the new field.
What does a carboxylase do?
Transfers CO2 groups with the help of biotin
How are reaction intermediates and transition states different?
Transition states are distinguished from reaction intermediates in that transition states are theoretical constructs that exist at the point of maximum energy, rather than distinct identities with finite lifetimes.
How do we name phenols with substituents?
Two groups on adjacent carbons are called ortho, or o-. Two groups separated by a carbon are called meta-, or m-. Two groups on opposite sides of the ring are called para-, or p-.
What is the formula for electric potential energy?
U = kQq / r
What is the formula for potential energy stored in a capacitor?
U=½ CV²
How to calculate E cell?
Used in place of E°cell when the cell is not at standard conditions: E cell= E°cell - (0.0592/ n) log Q
How do we find the mole fraction of a gas?
Using its partial pressure: PA= XA * PT where XA= moles of gas A/ total moles of gas
How do we calculate the number of moles being deposited on a plate?
Using the electrodeposition equation: Calculating Moles of Metal, It is Not Fun mol M = It/nF * where mol M is the amount of metal ion being deposited at a specific electrode, I is the current, t is time, n is the number of electron equivalents for a specific metal ion, and F is the Faraday constant. Note: This equation can also be used to determine the amount of gas liberated during electrolysis
What is the formula for electric potential near a dipole?
V= (kqd/ r²) cos θ
What is Ohm's Law?
V=IR
Why does valine have a higher melting point than Butane?
Valine is not only larger (increasing the dispersion forces), but it is also capable of strong dipole-dipole interactions (including hydrogen bonding).
Describe vapor pressure depression. What's the equation for it?
Vapor pressure depression follow Raoult's law. The presence of other solutes decreases the evaporation rate of a solvent without affecting is condensation rate, thus decreasing its vapor pressure. PA =XAP°A *where PA is the vapor pressure of the solvent A when solutes are present, XA is the mole fraction of the solvent A in the solution, and P°A is the vapor pressure of solvent A in its pure state. Note: vapor pressure depression also explains boiling point elevation- as the vapor pressure decreases the temperature (energy) required to boil the liquid must be raised.
Describe vacuum distillation
We use vacuum distillation whenever we want to distill a liquid with a boiling point over 150 degrees Celsius. By suing a vacuum, we lower the ambient pressure, thereby decreasing the temperature that the liquid must reach in order to have sufficient vapor pressure to boil. This allows us to distill compounds with higher boiling points at lower temperatures so that we do not have to worry about degrading the product.
How does the strength of a weak acid/ base compare to its conjugate?
Weak acids and bases tend to have conjugates that are also weak --but stronger than the conjugates of strong acids and bases
When do we reject the null hypothesis?
When P ≤ 0.05 or P < alpha
Describe a conductor in regard to charge
When a conductor is given a charge, the charges will distribute approximately evenly upon the surface of the conductor. Conductors are able to transfer and transport charged and are often used in circuits or electrochemical cells. Conductors are often conceptualized as nuclei surrounded by a sea of free electrons that are able to move rapidly throughout the material and are only loosely associated with positive charges. Conductors are generally metals, although ionic (electrolyte) solutions are also effective conductors.
Describe dielectrics in circuit capacitors
When a dielectric material is placed in a charged capacitor within a circuit --that is, still connected to a voltage source -- the charge on teh capacitor increases. The voltage must remain constant because it must be equal to that of the voltage source. By increasing the amount of charge stored on the capacitor, the dielectric has increased the capacitance of the capacitor by a factors of he dielectric constant. Thus, when a dielectric material is introduced into a circuit capacitor, the increase in capacitance arises from an increase in stored charge.
What does expansion and compression of a gas mean for work?
When a gas expands, we say work has been done by the gas and the work is positive. When a gas is compressed, we say work has been done on the gas and the work is negative.
How does light bend in response to indices of refraction?
When light enters a medium with a higher index of refraction from whince it came (n2>n1), it bends toward the normal (sinθ₂<sinθ₁). When light enters a medium with a lower index of refraction (n2<n1), it bends away from the normal (sinθ₂>sinθ₁)
What is Snell's Law? What is the equation for it
When light is in any medium besides a vacuum, its speed is less than c. There will thus be a refraction. Snell's law states that there's an inverse relationship between the index of refraction and the sine of the angle of refraction (measured from the normal): n₁sinθ₁=n₂sinθ₂
When do waves have a phase difference of λ/2 ?
When the crest of one wave lines up perfectly with the trough of another--they are perfectly out of phase
What do you get when you mix a strong acid and a weak base?
You get a salt but no water will be formed because weak bases are often not hydroxides. In this case, the cation of the salt is a weak acid and will react with the water solvent, reforming some of the weak base through hydrolysis: Reaction I: HCl (aq) + NH3 (aq) --> NH4+ (aq) + Cl- Reaction II: NH4+ (aq) + H2O --> NH3 (aq) + H3O+ (aq) The resultant H3O+ will cause the pH of the solution to be slightly acidic
What do you get when you mix a weak acid with a strong base?
You get a slightly basic solution because the salt hydrolyzes (due to reaction with water) resulting in formation of OH-: Reaction I: CH3COOH(aq) + NaOH(aq) --> Na+(aq) + CH3COO- (aq) + H2O Reaction II: CH3COO- (aq) + H2O (l) --> CH3COOH(aq) +OH-(aq)
Describe Young's double slit experiment
Young's double slit experiment shows the constructive and destructive interferences of waves that occur as light passes through parallel slits, resulting in minima (dark fringes) and maxima (bright fringes) of intensity.
What is the formula for latent heat?
aka Heat of transformation q= mL *L (latent heat) can be heat of fusion, vaporization, solidification etc.
What is attenuation?
aka damping it is a decrease n amplitude of a wave caused by an applied or nonconservative force
What is the Hawthorne effect?
aka observation bias a study's results are affected by participant's knowledge that they are taking part in an experience or being treated differently than usual
What is the formula for potential difference?
aka voltage: ∆V= Vb - Va = Wab/ q *where Wab is the work needed to move a test charge q through an electric field from point a to point b. If it is negative, this represents a decrease in electric potential energy.
virtual image
an image that forms at a location from which light rays appear to go but do not actually go
What are intermolecular bonds?
bonds between molecules
What are intramolecular bonds?
bonds within molecules
What gives rise to surface tension?
cohesion
Diverging lenses are
concave
What is the formula for the location of dark fringes (minima) in a multiple-slit lens set up
dsinθ=(n+(1/2))λ *where d is the distance between the two slits, θ is the angle between the line drawn from the midpoint between the two slits to the dark fringe and the normal, n is an integer indicating the number of the fringe, and λ is the wavelength of the incident wave
What is the fundamental unit of charge?
e = 1.6*(10^-19) C
How do we subtract vectors?
equivalent to addition of its negative: do addition with B being negative in value and facing the opposite direction
What is the formula for the doppler effect?
f¹= f (v± vD)/ (v( -/+)vs) *where f¹ is the perceived frequency, f is the actual emitted frequency, v is the speed of sound in the medium. vD is the speed of the detector, and vs is the speed of the source. Note: the upper sign should be used when the detector or source is moving toward the other object. The lower sign should be used when the detector or source is moving away from the other object. Top sign for toward. Bottom sign for away. It's detector/source as in Nintendo DS.
What is equipoise?
genuine uncertainty about which arm of a clinical trial will provide the most benefits or harms to patients, research subjects, or future patients
What is the only amino acid that does not have a chiral center?
glycine
Do example on page 374
good job
Draw Aspartate
good job
What is the conversion equation for log to ln?
logx = lnx / 2.303
What time of waves are sound waves?
longitudinal waves
Are silica gel and alumina polar or nonpolar?
polar
What emf do galvanic (voltaic cells) have?
positive: the discharge is spontaneous
In electrochemical cells, salt bridges:
prevent charge buildup in galvanic cells Note: electrolytic cells do not require a salt bridge; current flow is maintained by the battery
What is an adiabatic process?
process in which no heat exchange occurs between the system and the surroundings: Q= 0. This means that ∆U=-W
What is the formula for the rate of a reaction?
rate= Z * f *where Z is the total number of collisions per second and f is the fraction of collisions that are effective
What is an isovolumetric process?
reaction where the volume remains the same and thus no work is accomplished; aka isochoric. Here W=0 and this ∆U=Q.
Is carbon a reducing or oxidizing agent?
reducing agent
stereospecific
single reactant forms an unequal mixture of stereoisomers
What are diastereomers?
stereoisomers that share the came connectivity but are not mirror images of each other
intramolecular forces
strong attractive forces within the same molecule or compound
What is the only factor that can change Ksp?
temperature
In order to be transported from the skin to the liver via the bloodstream, vitamin D3 must...
travel through the circulatory system attached to a vitamin D-binding protein. Vitamin D3 is a fat-soluble molecule that comes from a steroid precursor. It is insoluble in aqueous environments despite its polar -OH group (this polar group is heavily outweighed by the many carbon atoms). In order to leave the cell, it needs no channel and cannot be contained by a vesicle, it travels freely through the lipid bilayer. The only way for it to travel through the aqueous environment of the blood, however, is attached to a polar molecule, like a protein.
What are combination reactions
two or more reactants react to form one product Ex:) 2H2 + O2 --> 2H2O A+B ---> C
What is the tan of 90 degrees?
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What is the formula for the root-mean-square speed of a gas particle?
urms= sqrt( (3RT)/M) *where R is the ideal gas constant, T is the temperature, and M is the molar mass in Kg (since we are using joules we must use kg/mol)
What is the formula for the propagation speed of a wave?
v= f*λ
What is the formula for the speed of sound?
v= sqrt (B/rho) *where B is the bulk modulus, a measure of the medium's resistance to compression (B increases from gas to light to sloid). And where "rho" is the density of the medium Note: because the bulk modulus increases disproportionately more than density as one goes from gas to liquid to solid, sound travels fastest through a solid and slowest through a gas.
What is the formula for change in velocity in respect to time?
v= v₀ + at
What is the formula for enthalpy of a reaction? What does the sign mean?
∆Hrxn=∆Hproducts-∆Hreactants A positive ∆Hrxn corresponds to an endothermic process, and a negative ∆Hrxn corresponds to an exothermic process
What is the standard enthalpy change formula involving bonds?
∆H°rxn= ∑∆Hbonds broken-∑∆Hbonds formed = total energy absorbed- total energy released
What is the formula for the standard heat of formation
∆H°rxn= ∑∆H°f,products -∑∆H°f,reactants
What is the formula for thermal expansion for solids?
∆L = αL∆T *where α is the coefficient of linear expansion Hint: when the temperature of an object changes, its length changes αL∆T (aLOT)
What is ∆Q when a system is exothermic?
∆Q <0
What is ∆Q when a system is endothermic?
∆Q >0
What is the formula for change in entropy?
∆S= Qrev / T *where Qrev is the heat gained or lost in a reversible process and T is the temperature in Kelvin The units are typically J/ (mol*K)
What is the formula for boiling point elevation?
ΔTb = iKbm *where i is the van't Hoff factor , Kb is a proportionality constant, and m is the molality of the solution Remember that the van't Hoff factor corresponds to the number of particles into which a compound dissociates in solution. For example. i=2 for NaCl. This temperature is in Kelvin.
What is the formula for sound level
β= 10 log (I/I₀)
What is the formula for comparing sound levels?
βf= βi + 10 log (If/Ii)
Formula for the emf of a battery when no current is running
ε= V+ (i*rinternal) *where ε is the emf, V is the voltage provided by the cell, i is the current through the cell, and rinternal is the internal resistance
What is the formula relating the wavelength and length of a standing wave on a string?
λ= (2L)/n *where n is a nonzero positive integer called the harmonic. The harmonic corresponds to the number of half-wavelengths supported by the string. As a shortcut, for strings attached at both ends, the number of antinodes present will tell you which harmonic it is.
What is the formula relating the wavelength and length of a standing wave in a closed pipe?
λ= (4L)/n
What is the van der Waals equation of state?
(P+(n²a)/V²)(V-nb) = nRT This equation attempts to correct for the deviations from ideality that occur when a gas does not closely follow the ideal gas law. *Here a and b are physical constants experimentally determined for each gas. The a term corrects for the attractive forces between molecules and as such will be smaller for gasses that are small and less polarizable. The b corrects for the volume of the molecules themselves. Larger molecules thus have larger values of b. a is the van der Waals term for the attractive forces. b is the van der Waals term for big particles.
Describe (R) and (S) forms of molecules
(R) and (S) are used for chiral (stereogenic) centers in molecules. We go through a set sequence to determine this absolute configuration: Step 1: Assign Priority Using the Cahn-Ingold-Prelog priority rules, assign priority to the four substituents, looking only at the atoms directly attached to the chiral center. Once again, higher atomic number takes priority over lower atomic number. If the atomic numbers are equal, priority is determined by the combination of the atoms attached to these atoms; if there is a double bond it is counted as two individual bonds to that atom. Step 2: Arrange in Space Orient the molecule in 3D space so that the atom with the lowest priority is at the back of the molecule Step 3: Draw a circle
What is the cosine of 30 degrees?
(sqrt3)/ 2
What is the tan of 30 degrees?
(sqrt3)/3
What is the formula for the rate at which nuclei decay?
(∆n/∆t)= -λn *where λ is the decay constant and n is the number that remain
What is the cosine of 45 degrees?
(√2)/2
What is the sine of 45 degrees?
(√2)/2
What is the sine of 60 degrees?
(√3)/2
What are the effects of the signs of ∆H and ∆S on spontaneity? In cases such as: +∆H and +∆S +∆H and -∆S -∆H and +∆S -∆H and -∆S
* If +∆H and +∆S, then the reaction is only spontaneous at high temperatures *If +∆H and -∆S, then the reaction is nonspontaneous at all temperatures *If -∆H and +∆S, then the reaction is spontaneous at all temperatures *If -∆H and -∆S, then the reaction is spontaneous at low temperatures Hint:∆G is temperature dependent when ∆H and ∆S have the same sign. Don't forget that temperature here can only be in Kelvins, there is no negative Kelvin
Describe how vasodilation and vasoconstriction play a role in thermoregualation
*Arterial vasodilation maximizes heat loss to cool down the body. This brings a large quantity of blood to the skin, which accelerates the evaporation of sweat by maximizing heat energy available for the liquid-gas exchange that sweat does. *Arterial vasoconstriction limits the quantity of blood reaching the skin. Minimizing heat energy that is available to be lost.
How do you name carboxylic acids? Cyclic carboxylic acids? Carboxylic acid salts? Dicarboxylic acids?
*In the IUPAC system of nomenclature, carboxylic acids are named by adding the suffix -oic acid to the parent root when the carboxylic acid is the highest priority functional group. When this is true, the carbonyl carbon becomes carbon one. *Cyclic carboxylic acids are named by listing the cycloalkane with the suffix carboxylic acid. *Salts of carboxylic acids are named beginning with the cation, followed by the name of the acid with the ending -oate replacing -oic acid. *Dicarboxylic acid IUPAC names have the suffix -dioic acid: ethanedioic acid, propanedioic acid, butanedioic acid, etc.
How do you use the right-hand rule to determine the direction of a magnetic field involving a moving point charge? What formula relates to this?
*Point your thumb in the direction of the velocity: this indicates the direction of movement, like a hitchhiker's thumb *Point your fingers in the direction of the magnetic field: these are the field lines. They are parallel like the uniform magnetic field lines. *Your palm is the force on a positive charge: you might give a "high five" to a positive person *The back of your hand is the force on the negative charge: you might backhand a negative person Th formula that relates to this is FB=qVBsin
What are the rules of the law of mass action?
*The concentrations of pure solids and pure liquids fo not appear in the equilibrium constant equation. This is because the equilibrium expression is technically based on the activities of compounds, not concentrations; the activities of pure solids and liquids are defined to be 1. * Keq is the characteristic of a particular reaction at a given temperature; the equilibrium constant is temperature dependent. * The larger the value of Keq, the farther to the right the equilibrium position. * If the equilibrium constant for a reaction written in one direction is Keq, the equilibrium constant for the reverse reaction is 1/Keq.
Which amino acids are hydrophilic? Which are hydrophobic? Where are they found?
*all amino acids with charged side chains (H,R,K, and D, E) are hydrophilic as are the amides (N & Q) and Serine and Threonine (S &T) --She's Taking No Questions. These amino acids are thus typically found on the surface of proteins. *amino acids with long akyl side chains (A, I, L, V, and F) are all strongly hydrophobic and thus likely to be found in the interior of proteins -- Very Fobic And Loving It *The remaining amino acids fall in the middle and classify as neither.
pyridinium chlorochromate (PCC)
*oxidizes primary alcohols to aldehydes --lacks the water necessary to hydrate the aldehyde so it cannot oxidize it any further *oxidizes secondary alcohols to ketones
What is the oxidation number of a group IIA element in a compound?
+2
What is the minimum value of 2 cosθ - 1?
-3 The minimum value of the cosine funciton is -1 (cos 180 degrees = -1). Therefore the minimum value of 2 cosθ - 1 is 2 x (-1) -1 = -3
Describe peptide bonds
-between amino acids -primary structure -type of covalent bond -Peptide bonds are formed when two amino acids are joined together by dehydration synthesis. -Peptide bonds are broken by hydrolysis. Since peptide bonds are resonant, they have a partial double bond character, which restricts them to a planer molecular geometry.
Describe sp2 hybridization
1. Trigonal planar structure 2. sp2 hybridization creates 3 identical orbitals of intermediate energy and length and leaves one unhybridized p orbital 3. 3 effective pairs of electrons surround the carbon (double bond treated as one effective pair) * a c-to-c double bond is an sp2 hybridization
A voltaic cell provides a current of 0.5 A when in a circuit with a 3 ohm resistor. If the internal resistance of the cell is 0.1 ohms, what is the voltage across the terminals of the battery when there is no current flowing?
1.55 V This question tests our understanding of batteries in a circuit. The voltage across the terminals of the battery when there is no current flowing is referred to as the electromotive force (emf or εof the battery). However, when a current is flowing through the circuit, the voltage across the terminals of the battery is decreased by an amount equal to the current multiplied by the internal resistance of the battery. Mathematically this is given by the equation: V= ε - (i*rinternal) To determine the emf of the battery, first, calculate the voltage across the battery when the current is flowing. For this we can use Ohm's law: V=IR =(0.5A)(3 ohms) = 1.5 V Because we know the internal resistance of the battery, the current, and the voltage, we can calculate the emf: ε= V+ (i*rinternal) =1.5 V + (0.5 A)(0.1 ohms) = 1.5 + 0.05 = 1.55 V
What is the formula comparing focal length, object distance, image distance, and radius of curvature for spherical mirrors?
1/f = (1/o) + (1/i) = 2/r
What is the formula for the focal length of thin spherical lenses (lenses with negligible thickness)?
1/f = (1/o) + (1/i) = 2/r
What is the formula for the focal length of lenses where the thickness cannot be neglected?
1/f = (n-1) [(1/r₁) - (1/r₂)]
What is Avogadro's number?
6.02 x 10^23 it tells us how many units of anything per mole
ZnCO3 (Ksp = 2 X10^-10) s added to a saturated solution of Zn(OH)2 (Ksp = 3x10^-16) and a precipitate is noted. The identity of the precipitate is most likely: A. Zn(OH)2 B. Zn C. H2CO3 D. ZnCO3
A A saturated solution of Zn(OH)2 implies hat the addition of any Zn2+ or OH- ions would cause a precipitate to form. ZnCO3 is more soluble than Zn(OH2) and as such, would dissociate into Zn2+ and CO₃²- ions. This would lead to the precipitation of Zn(OH)2.
Describe Bronsted-Lowry acids and bases.
A Bronsted-Lowry acid is a species that donates hydrogen ions (H+), while a Bronsted-Lowry base is a species that accepts them.
Describe Lewis acids and bases
A Lewis acid is defined as an electron pair acceptor and a Lewis base is defined as an electron-pair donor, The electron pair being donated is a lone pair and is not involved in any other bonds.
What is the direction of current in a discharging cell?
A discharging cell is galvanic (voltaic) cell. Here current flows from the positive, higher potential end of the cell around the circuit to the negative, lower potential end of the cell.
Describe buffer solutions
A buffer solution consists of a mixture of a weak acid and its salt (which is composed of its conjugate base and a cation) or a mixture of a weak base and its salt (which is composed of its conjugate acid and an anion).
Describe optical activity and describe the labeling of molecules based on optical activity
A compound is optically active if it has the ability to rotate plane-polarized light. Ordinary light is unpolarized, which means that it consists of waves vibrating in all possible planes perpendicular to its direction of propagation. A polarizer allows light waves oscillating only in a particular direction to pass through, producing plane-polarized light. Optical activity refers to the rotation of this plane-polarized light by a chiral molecule. A compound that rotates the plane of polarized light to the right, or clockwise, is dextrorotatory (d-) and is labeled (+). A compound that rotates light toward the left, or counterclockwise, is levorotatory (l-) and is labeled (-). The direction of rotation cannot be determined from the structure of a molecule and must be determined from the structure of a molecule and must be determined experimentally. Note: d- and l- are NOT the same as D- and L- configs found on carbohydrates (D-, R-, S-, and L- can be determined by structure)
What is the difference between a constant-pressure calorimeter and a constant-volume calorimeter?
A constant-pressure calorimeter (coffee cup calorimeter) is exposed to constant (atmospheric pressure). As the reaction proceeds, the temperature of the contents is measured to determine the heat of the reaction. A constant-volume calorimeter (bomb calorimeter) is one in which heats of certain reactions (like combustion_ can be measured indirectly by assessing temperature change in a water bath around the reaction vessel.
What is potentiometric titration?
A form of redox titration where no indicator is used. Instead, the electrical potential difference (voltage) is measured using a voltmeter. As a redox titration progresses, its voltage changes; this is analogous to following an acid-base titration with a pH meter instead of a color indicator.
A solution is prepared with an unknown concentration of a theoretical compound with a Ka of exactly 1.0. What is the pH of this solution? A. Higher than 7 B. Exactly 7 C. Less than 7 D. There is not enough information to answer the question.
A higher Ka implies a stronger acid. Weak acids usually have a Ka that is several orders of magnitude below 1. The pKa of a compound is the pH at which there are equal concentrations of acid and conjugate base, the pKa of this compound would be -log 1 = 0. Which such a low pKa, this compound must be an acid. Therefore the pH of any concentration of this compound must be below 7.
What is the hypodermis?
A layer of connective tissue that connects the skin to the rest of the body. This layer contains fat and fibrous tissue.
Strecker synthesis
A method of synthesizing amino acids that uses condensation between an aldehyde and hydrogen cyanide, followed by hydrolysis.
What is total internal reflection?
A phenomenon in which all the light incident on a boundary is reflected bac to the original material. This results with any angle of incident greater than the critical angle, θc.
What is a type II error?
A type II error occurs when we incorrectly fail to reject the null hypothesis. It is the likelihood that we report no difference between two populations when one actually exists. This is a false negative -- a guilty man is set free
Describe an ideal voltmeter
A voltmeter, like an ammeter, requires a circuit to be active. Voltmeters are used to measure the voltage drop across two points in a circuit. They are wire in parallel to these two points. Because the foal with any meter is to minimize its impact on the rest of the circuit, and voltmeters are wired in parallel, an ideal voltmeter has infinite resistance.
Describe the structure of acetone
Acetone exists in two forms, with the keto form predominating. This occurs because the carbon-oxygen double bond (the carbonyl bond) is much stronger than the carbon-carbon bond. Acetone has a low boiling point and is polar and aprotic --there is no hydrogen attached to electronegative atoms (FON) (this makes it unable to participate in hydrogen bonding--which is the hallmark of a protic solvent, such as ethanol).
Describe anhydrides
Acid anhydrides are formed via the removal of water from two molecules of carboxylic acid --through nucleophilic acyl substitution. They are highly reactive compounds and are named after the carboxylic acid that was used as a reactant. Acid anhydrides are not soluble in water--due to their high reactivity, upon coming into contact with water, they reform the original carboxylic acid.
Describe the acyl derivatives
Acyl derivatives encompass all molecules with a carboxylic acid-derived carbonyl, including carboxylic acids, amides, esters, anhydrides, and others. These reactions are favored by a good leaving group. Note: Remember, weak bases, which are often the conjugate bases of strong acids, make good leaving groups. These reactions are also favored in either acidic or basic conditions, which can alter the reactivity of the electrophile and nucleophile.
What is disproportionation?
Aka dismutation, it is a specific type of redox reaction in which an element undergoes both oxidation and reduction in producing its products.
Describe precision
Aka reliability It is the ability of the instrument to read consistently, or within a narrow range.
Describe accuracy
Aka validity It is the ability of an instrument to measure a true value. For example. an accurate scale should register a 170-pound person's weight as 170 pounds.
What causes nonbonded strain?
Aka van der walls repulsion This results when nonadjacent atoms or groups compete for the same space. Nonbonded strain is the dominant source of steric strain in the flagpole interactions of the cyclohexane boat confirmation. To alleviate strain, cyclohexanes adopt various nonpolar conformations. Cyclobutane puckers into a slight V shape; cyclopentane adopts what is called an envelope conformation; and cyclohexane exists in mainly three conformations called the chair, boat, and twit-or skew boat forms. The most stable conformation of cyclohexane is the chair conformation, which minimizes all three types of strain.
Is alcohol a good or poor leaving group?
Alcohol is a poor leaving group. However they can be protonated or reacted to form much better leaving groups
How do we name molecules that contain an alcohol?
Alcohols are named in the IUPAC system by replacing the -e ending of the root alkane with the ending -ol. If the alcohol is the highest priority functional group, the carbon atom attached to it receives the lowest possible number. Alternatively, the common naming practice is to name the alkyl group as a derivative, followed by alcohol. When the alcohol is not the highest priority group, it is named as a substituent, with the prefix hydroxy-
Describe alcohol as a protecting group
Aldehydes and ketones can be reacted with two equivalents of an alcohol or a diol, forming acetals (primary carbons with two -OR groups and a hydrogen atom) or ketals ( secondary carbons with two-OR groups). Carbonyls are very reactive with strong reducing agents like lithium aluminum hydride (LiAlH4). Acetals and ketals on the other hand do not react with LiAlH4. The acetal or ketal thereby protects the aldehyde or ketone from reaction. After reducing other functionalities in the molecule, the acetal or ketal can be reverted back to a carbonyl with aqueous acid, a step called deprotection.
How are aldehydes named
Aldehydes are named by replacing the -e at the end of an alkane name with the suffix -al. Common names for the first five aldehydes are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and valeraldehyde. When aldehydes are named as substituents, use the prefix oxo-. If the aldehyde is attached to a ring, the suffix -carbaldehyde is used instead. Note: Notice that these common names have a pattern that can help us: form- means one carbon and acet- means two carbons
Describe aldosterone
Aldosterone is a steroid hormone that is secreted by the adrenal cortex in response to decreased blood pressure: Decreased blood pressure stimulates the release of renin from juxtaglomerular cells in the kidney. Renin then cleaves angiotensinogen, a liver protein, to form angiotensin I. This peptide is then metabolized by ACE in the lungs to form angiotensin II, which promotes the release of aldosterone from the adrenal cortex. Note: aldosterone will also increase potassium and hydrogen ion excretion
Compare and contrast galvanic cells and electrolytic cells
All types f electrochemical cells have a reduction reaction occurring at the cathode, an oxidation reaction occurring at the anode, a current flowing from cathode to anode, and electrons from anode to cathode. However, electrolytic cells, in almost all their characteristics and behavior, are otherwise the opposite of galvanic cells. Whereas galvanic cells house spontaneous oxidation-reduction reactions that generate electrical energy electrolytic cells house nonspontaneous reactions that require an input of energy to proceed. Therefore, the change in free energy for electrolytic cells is positive.
Describe alpha decay
Alpha decay is the emission of an alpha-particle, which is a 4,2He nucleus that consists of 2 protons, 2 neutrons, and 0 electrons. The alpha particle is very massive compared to a beta particle and carries double the charge. Alpha particles interact with matter very easily; hence they do not penetrate shielding (such as lead sheets) very extensively. The emission of an alpha-particle means that the atomic number of the daughter nucleus will be two less than that of the parent nucleus, and the mass number will be four less. Note: alpha particles do not have any electrons so they carry a charge of +2
What is an isochoric process?
Also called an isovolumetric process. It is a process in which volume stays constant as pressure changes so ∆V=0 and no work is done. (there is no area to calculate in the P-V curve)
How does current flow?
Although current involves negatively charged particles (electrons) moving in a circuit from low potential to high potential, current is defined as the movement of positive charge from the high-potential end of a voltage source to the low potential end. This means that the direction of current is the direction in which a positive charge would flow (from higher potential to lower potential). Thus, the direction of current is opposite to the direction of actual electron flow.
How does temperature affect resistance?
Although not evident from the resistance equation, most conductors have greater resistance at higher temperatures. This is due to increased thermal oscillation of the atoms in the conductive material, which produces a greater resistance to electron flow. Because temperature is an intrinsic quality of all matter, we can think of the resistivity as a function of temperature. A few materials do not follow this general rile, including glass, pure silicon, and most semiconductors
What is an amide?
Amides are defined as organic compounds in which an amine functionality is directly bonded to a carbonyl carbon.
What are lactams?
Amides that are cyclic are called lactams and are named by replacing -oic acid with -lactam. They may also be named by indicating the specific carbon that is bonded during cyclization of the compound.
How is acyl nucleophilic substitution a condensation reaction?
Amides, esters, and anhydrides are all carboxylic acid derivatives. Each of these is formed by a condensation reaction with a carboxylic acid--a reaction that combines two molecules into one, while losing a small molecule. In this case, the small molecule is water, which is created from the hydroxyl group of the carboxylic acid and a hydrogen associated with the incoming nucleophile.
What is an Arrhenius acid? An Arrhenius base?
An Arrhenius acid will dissociate to form an excess of H+ in solution and an Arrhenius base will dissociate to form an excess of OH- in solution. These behaviors are generally limited to aqueous acids and bases. Arrhenius acids and bases are easily identified; acids contain H at the beginning of their formula (HCl, HNO3, H2SO4, and so one) and bases contain OH at the end of their formula (NaOH, Ca(OH)2 Fe(OH)3, and so one.
Describe an ideal ammeter
An ammeter requires a circuit to be active. An ideal ammeter has zero resistance and no voltage drop across itself. It is best placed in series where the current is being measured.
What is an amphoteric species?
An amphoteric species is one that reacts like an acid in a basic environment and like a base in an acidic environment. The most common example is water. When water reacts with a base it behaves like an acid: H2O + B- -->HB + OH- When water reacts with an acid it behaves as a base: HA+ H2O ---> H3O+ + A-
Sarin is a potent organophosphate that can be used in chemical warfare. AS an inhibitor of acetylcholinesterase, sarin causes excessive buildup of acetylcholine in all synapses where it is a neurotransmitter. Which of the following symptoms would most likely be seen in an individual with sarin poisoning? A: increased urination and increased sweating B: Increased urination and decreased sweating C: Decreased urination and increased sweating D: decreased urination and decreased sweating
An excess of acetylcholine will lead to activation of all parasympathetic neurons, preganglionic sympathetic neurons, and the postganglionic sympathetic neurons that innervate sweat glands. Because the parasympathetic nervous system causes contraction of the bladder, one would expect increased urination. The increased activation of the sweat glands would lead to increased sweating as well.
Describe an insulator in regard to charge
An insulator will not easily distribute a charge over its surface and will not transfer that charge to another neutral object very well -- especially not to another insulator. On a molecular level, the electrons of insulators tend to be closely linked with their respective nuclei. By extension, most nonmetals are insulators. Experimentally, insulators serve as dielectric materials in capacitors, as well as in isolating electrostatic experiments from the environment to prevent grounding.
What is the geometry of the hexafluoroaluminate ion (AlF63-)?
An ion consisting of a central metal ion and six ligands is expected to have an octahedral geometry: a top atom, a bottom atom, and four middle atoms
What is Newton's first law?
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless s net force acts upon it: Fnet= ma = 0
When is an object considered chiral?
An object is considered chiral if its mirror image cannot be superimposed on the original object; this implies that the molecule lacs an internal plane of symmetry. Note: achiral objects have mirror images that can be superimposed
When does an object float? When does it sink?
An object will float if its average density is less than the average density of the fluid it is immersed in. It will sink if its averaged density is greater than that of the fluid.
Describe the reactivity of the carboxylic acid derivatives
Anydrides are most reative, followed by esters (which are essentially tied with carboxylic acids, then finally amides. This can be explained by the structure of these molecules. Anhydrides, with ther resonance stabilization and three elecltron withdrawing oxygen atoms, are the most electrophillic. Esters, by comparison, laco one wlectron withdrawing carbonyl oxygen and are slightly less reactive. Finally, amides, with an elctron DONATING amino group, are the least reaactive toward nucleophiles.
How do you solve log1/A?
As -logA
Why does S2 have a longer double bond than O2?
As one descends a group in the periodic table, atomic radius increases and Zeff decreases. Due to a larger electron cloud (more inner electrons) the S to S bond needs to be longer.
How is X^-A solved?
As: 1/(X^A)
How is (X/Y)^A solved?
As: X^A/Y^A
A mercury barometer is primarily affected by atmospheric pressure. What would happen to the level of the mercury in the column if: *the barometer was moved to the top of a mountain *the barometer was placed ten meters under water
At the top of the mountain, atmospheric pressure is lower, causing the column to fall. Under water, hydrostatic pressure is exerted on the barometer in addition to atmospheric pressure causing the column to rise.
Describe the atomic radius trned?
Atomic radius tends to decrease from left to right across a given row of the table. This is because, as one moves across the row, the effective nuclear charge increase, drawing in the outermost electrons. It also increases a you move down the group as you add more subshells.
How are the electrodes set up in an electrolytic cell?
Because electrolysis is nonspontaneous, the electrode (Anode or cathode) can consist of any material so long as it can resist the high temperatures and corrosion of the process. Note: electrolytic cells rely on batteries to supply sufficient energy to drive the oxidation-reduction reaction in the direction that is thermodynamically unfavorable (spontaneous)
Which type of nuclear decay could be detected in an atomic absorption spectrum?
Because gamma radiation produces electromagnetic radiation (rather than nuclear fragments), it can be detected on an atomic absorption spectrum.
Why isnt [H2O] included in the Kw equation?
Because water only dissociates a tiny amount, meaning there is so much water compared to the amount of H+ and OH- ions that the concentration of water is considered to be constant. So it would cancel out
What are beta- carboxylic acids?
Beta-carboxylic acids are dicarboxylic acids in which each carboxylic acid is positioned on the beta carbon of the other. These compounds are notable for the high acidity of the alpha-hydrogens located on the carbon between the two carboxyl groups. Loss of this acidic hydrogen atom produces a carbanion which is stabilized by the electron-withdrawing group of both carboxyl groups.
Describe beta decay
Beta-decay is the emission of a beta particle, which is an electron and is given the symbol e- or beta-. Electrons do not reside in the nucleus, but they are emitted by the nucleus when a neutron decays into a proton, a beta-particle, and an antineutrino. Because an electron is singly charged and 1836 times lighter than a proton, the beta radiation from radioactive decay is more penetrating than alpha radiation. In some cases of induced decay (positron emission), a positron is released which has the mass of an electron but carries a positive charge. The position is given the symbol e+ or beta+.
List the structures in the excretory pathway, from where filtrate enters the nephron to the excretion of urine from the body.
Bowman's space --> proximal convoluted tuble --> descending limb of the loop of Henle -- ascending limb of the lop of Henle --> distal convoluted tubule --> collecting duct --> renal pelvis --> ureter --> bladder --> urethra
An experimenter is attempting to investigate the effect of a new antibiotic on E. coli. He plates cells and administers one milliliter of the antibiotic. Which of the following is an appropriate negative control in this experiment? A. A plate with no cells that was coated with one milliliter of antibiotic B. A plate with E.coli and no additional treatment C. A plate with E.coli and one milliliter of isotonic saline D. A plate of epithelial cells treated with one milliliter of antibiotic
C. A plate with E.coli and one milliliter of isotonic saline The purpose of a control is to keep the conditions of two experiments as close as possible to establish causality. In this case, the one milliliter volume addition might have impacted the growth of E. coli; thus we must control for this by administering an equal volume of a theoretically inert compound to a plate of E.coli.
Which of the following would best establish a causal link? A. A cross-sectional study using survey data for hand-washing and colds. B. A case-control study of an exposure during childhood and development of a certain disease later in life C. A randomized clinical controlled trial of a new antipyretic drug D. An IQ test where the results are later segregated by gender
C. A randomized clinical controlled trial of a new antipyretic drug An experiment will always establish a clearer causal link than an observational study. A, B, and D are all examples of observational studies
Describe chromium in oxidation
Chromium is a strong oxidizing agent that oxidizes primary alcohols all the way to carboxylic acids and secondary alcohols to ketones. Common examples of chroimium0conaining oxidizing agents include sodium and potassium dichromate salts (Na2Cr2O7 and K2Cr2O7). Again, as with other strong oxidizing agents, these will fully oxidize primary alcohols to carboxylic acids and secondary alcohols to ketones.
What is autoionization?
Due to its amphoteric nature, water can react with itself, this is the process known as autoionization: H2O (l) + H2O(l) ↔ H3O+ (aq) + OH-(aq)
What are the major waste products excreted in urine?
Dump the H.U.N.K *H+ *urea *NH3 * K+
Describe closed pipes
Closed pipes are closed on one end and open on the other-- thus one end is an antinode and the other is a node. Thef irst harmonic in a closed pipe consists of only the node at the closed end and the antinode at the open end. In a sinusoidal wave, the distance from a node to the following antinode is one-quarter wavelength. Thus, unlike strings or open pipes, the harmonic in a closed pipe is equal to the number of quarter-wavelengths supported by the pipe. Note: Because the closed end must have a node and the open end must have an antinode, there can only be odd harmonics in a closed pipe.
Describe closed systems
Closed systems are capable of exchanging energy, but not matter, with the surroundings. For example, gasses in vessels can move pistons but wont leave the system.
Describe capacitors in parallel
Capacitors wired in parallel, produce a resultant capacitance that is equal to the sum of the individual capacitances. Therefore, CP increases as more capacitors are added. Note: Just as we saw with resistors in parallel, the voltage across each parallel capacitor is the same and is equal to the voltage across the source.
Describe the hydrogen bonding of carboxylic acids
Carboxylic acids are polar because they contain a carbonyl group and can also form hydrogen bonds because they contain a hydrogen bonded to a very electronegative atom (in this case, as the hydroxyl oxygen). Carboxylic acids display particularlyly strong intermolecular attractions because both the hydroxyl oxygen and carbonyl oxygen can participate in hydrogen bonding. As a result, carboxylic acids tend to form dimers: pairs of molecules connected by two hydrogen bonds. Multiple hydrogen bonds elevate the boiling and melting points of carboxylic acids past those of corresponding alcohols. Boiling points also increase with increasing molecular weight.
Describe the synthesis of amides from carboxylic acids. How are the resultant amides named?
Carboxylic acids can be converted into amides if the incoming nucleophile is ammonia (NH3) or an amine. This can be carried out in either an acidic or basic solution to drive the reaction forward. Note that loss of hydrogen from the nucleophile is required for this reaction to take place. Thus only primary and secondary amine will undergo this reaction. Amides are named by replacing the -oic acid suffix with amide in the name of the parent carboxylic acid. Any alkyl groups on the nitrogen are placed at the beginning of the name with the prefix N-. Amides exist in a resonance state where delocalization of electrons occurs between the oxygen and nitrogen atoms.
What affect does changing the concentrations of a conjugate pair but not the ratio have on the Henderson-Hasselbalch equation?
Changing the ratio of the conjugate base to the acid would lead to a change in the Ph of the buffer solution. But when you change the concentration while maintaining a constant ratio, it is the buffering capacity --the ability to which the system can resist changes in pH-- that is changed. For example, if you were to double the concentrations of both the acid and its conjugate base, while pH would not change, the buffering capacity would increase such that addition of a small amount of acid to base will now cause even less deviation in the pH.
After randomization, it is discovered that one group in a study has almost twice as many women as the other. What should the researchers do?
Check the randomization algorithm; if it is fair, continue with the research. Note: participants should never be assigned by the researcher, nor should one continue randomizing samples to reach a desired outcome -- these are likely to introduce more error than leaving unequal groups.
What are cohort studies?
Cohort studies are those in which subjects are sorted into groups based on differences in risk factors ( exposures), and then assessed at various intervals to determine how many subjects in each group had a certain outcome. For example, a study in which 10 smokers and 100 nonsmokers are followed for 20 years while counting the number of subjects who develop lung cancer in each group would be an example of a cohort study. Note: A longitudinal study is an observational research method that follows the same subjects over time. Therefore, a cohort study is a form of longitudinal study.
What are conformational isomers?
Conformational isomers or conformers are stereoisomers that differ in rotation around single ( sigma) bonds. Of all of the isomers, conformational isomers are the most similar. Conformational isomers are, in fact, the same molecule, only at different points in their natural rotation around single (sigma) bonds. Conformational isomers arise from the fact that varying degrees of rotation around single bonds can create different levels of strain.
What are conservative forces? How can they be determined?
Conservative forces are those that are path independent and that do not dissipate energy. The two most common are gravitational and electrostatic. Methods for determining if a force is conservative are: A. Consider the change in energy of a system in which the system is brought back to its starting position. If the net change is zero regardless of the path taken to get back to its original position, then the forces acting on the object are conservative. The energy that was "spent" will be regained. B. Consider the change in energy of a system moving from one setup to another. If the energy change is equal regardless of the path taken, then the forces acting on the object are all conservative.
How to use the right-hand rule for a cross product resultant vector
Consider a resultant where C= A x B: 1. Start by pointing your thumb in the direction of vector A 2. Extend your fingers in the direction of vector B. 3. Your palm established the plane between the two vectors. The direction your palm points is the direction of the resultant C.
Describe standing waves
Consider the case when both ends of a string are fixed and traveling waves excited in the string. Certain wave frequencies will cause interference between the traveling wave and its reflected wave such that they form a waveform that appears to be stationary. IN this case, the only apparent movement of the string is fluctuation at fixed pints along the length of the string. These waves are known as standing waves. Points in the wave that remain at rest(where amplitude is constantly 0) are known as nodes. Points midway between the nodes fluctuate with maximum amplitude and are known as antinodes.
What is critical speed? How is it calculated?
Critical speed is the speed at which a fluid can maintain laminar flow; beyond it , turbulent flow occurs. It is calculated by: vc= (NR* viscosity)/ (rho* D) *NR is a dimensionless constant called the Reynolds number which depends on factors such as the size, shape, and surface roughness of any objects within the fluid *D is the diameter
What are cross-sectional studies?
Cross-sectional studies attempt to categorize patients into different groups at a single point in time. For example, a study to determine the prevalence of lung cancer in smokers and nonsmokers at a given point in time would be an example of a cross-sectional study
What is current? What is the formula for it?
Current is the amount of charge Q passing through the conductor per unit time, ∆t: I= Q/ ∆t The SI unit of current is the ampere (1 A = 1 C/S)
How do you name monatomic anions?
Drop the ending of the name of the element and add -ide Ex: H- -->Hydride F- --> fluoride O2- --> Oxide S2- --> Sulfide N3- --> Nitride
What is decarboxylation?
Decarboxylation describes the complete loss of the carboxyl group as carbon dioxide. This is a common way of getting rid of a carbon from the parent chain. 1,3-dicarboxylic acids and other beta-keto acids may spontaneously decarboxylate when heated. Under these conditions, the carbonyl group is lost and replaced with hydrogen. Because both the electrophile and nucleophile are in the same molecule, the reaction proceeds through a six-membered ring in its transition state. The enol that is finally formed from the destruction of the ring tautomerizes to the more stable keto form.
Describe detection bias
Detection bias results from educated professionals using their knowledge in an inconsistent way. Because prior studies have indicated there is a correlation between two variables, finding one of them increases the likelihood that the researcher will search for the second. For example, high blood pressure and diabetes Mellitus are more common in the obese population; thus, a physician may screen obese patients for hypertension and diabetes at a higher rate than healthy-weight patients, inflating the true value of the secondary measurement.
How does the diffraction pattern for a single slit differ from a slit with a thin lens?
Diffraction through a single slit does not create characteristic fringes when projected on a screen, although the light does spread out. When a lens is introduced into the system, the additional refraction of light causes constructive and destructive interference, creating fringes.
Describe distillation
Distillation takes advantage of differences in boiling point to separate two liquids by evaporation and condensation. The liquid with the lower boiling point will vaporize first, and the vapors will rise up the distillation column to condense in a water cooled condenser. This condensate then drips down into a vessel. The end product is called the distillate. The heating temperature is kept low so that the liquid with the higher boiling point will not be able to boil and therefore will remain in liquid in the initial container.
Describe simple distillation
Distillation takes advantage of differences in boiling point to separate two liquids by evaporation and condensation. The liquid with the lower boiling point will vaporize first, and the vapors will rise up the distillation column to condense in a water cooled condenser. This condensate then drips down into a vessel. The end product is called the distillate. The heating temperature is kept low so that the liquid with the higher boiling point will not be able to boil and therefore will remain in liquid in the initial container. Note: This technique should only be used to separate liquids that boil below 150 degrees Celsius and have at least a 25 degrees celsius difference in boiling points.
What type of reactions are not redox reactions?
Double-displacement/ Metathesis Reactions Note: This means that in double-displacement reactions where both reactants and both products are aqueous, there is no net ionic equation.
What is the difference between the two types of beta decay?
During beta- decay, a neutron is converted into a proton and a beta- particle (Z= -1, A=0) is emitted. Hence the atomic number of the daughter nucleus will be one higher than that of the parent nucleus, and the mass number will not change. During beta+ decay, a proton is converted into a neutron and a beta+ particle (Z=+1, A=0) is emitted. Hence, the atomic number of the daughter nucleus will be one lower than that of the parent nucleus and the mass number will not change.
How do you calculate the standard electromotive force?
Emf or E°cell: E°cell= E°red, cathode - E°red,anode
Describe enantiomers
Enantiomers have the same connectivity but opposite configurations at every chiral center in the molecule. Enantiomers have identical physical and chemical properties with two notable exceptions: optical activity (they rotate plane-polarized light in opposite directions) and reactions in chiral environments.
What do you get when you mix a strong base and a strong acid?
Equimolar amounts of salt and water. The acid and base neutralize each other so the resulting solution is neutral (pH=7). Note: here the salt does not react with the water because it has been neutralized
Describe the synthesis of esters. How are they named?
Esters are a hybrid between a carboxylic acid and an ether (ROR), which can be made by reacting carboxylic acids with alcohols under acidic conditions. Esterification is a condensation reaction with water as a side product. In acidic solutions, the carbonyl oxygen can be protonated, which enhances the polarity of the bond, thereby placing additional positive charge on the carbonyl carbon and increasing its susceptibility to nucleophilic attack. This condensation reaction occurs most rapidly with primary alcohols. Esters are named in the same manner as salts of carboxylic acids: replace the suffix -ioic with -oate. Note: esters can also be obtained from the reaction of anhydrides with alcohols.
What are lactones?
Esters that are cyclic are called lactones an are named by replacing -oic acid with -lactone.
In what directions do current and electrons flow through electrochemical cells (batteries)
For all electrochemical cells, the movement of electrons is from anode to cathode, and the current (I) runs from cathode to anode --in physics it is typical to state that current is the direction of flow of a positive charge through a circuit.
What is Coulomb's Law for calculating electrostatic force?
Fe= kq₁q₂ / r² *where Fe is the magnitude of electrostatic force, k is Coulomb's constant, q₁ and q₂ are the magnitudes of the two charges, and r is the distance between the charges.
Describe ferromagnetic materials
Ferromagnetic materals have unpaired electrons and permanent atomic magentic dipoles that are normally oriented randomly so that the material has no net magnetic dipole. However, ferromagentic materials will become strongly magnetized when exposed to a magnetic field or under certain temperatures. Common ferromagnetic materials include iron, nickel, and cobalt. Bar magnets are ferromagnetic materials with a north and south pole. Field lines exit the north pole and enter the south pole. Because magnetic field lines are circular, it is impossible t have a monopole magnet.
What is the formula for the magnitude of gravitational force between two objects?
Fg= Gm₁m₂/ r² *where G is the universal gravitational constant (6.67E-11 (N*m²) / Kg²) and r² is the distance between the centers of the two masses
What is the formula for the weight of a buoyant object?
Fg= pVg
Describe the loop of Henle
Filtrate from the convoluted tubule enters the descending limb of the loop of Henle, which dives deep into the medulla before turning around to become the ascending loop of Henle. The descending limb is permeable only to water, and the medulla has an ever-increasing osmolarity as the descending limb travels deeper into tit. As the descending limb transverses deeper into the medulla, the increasing interstitial concentration favors the outflow of water from the descending limb, which is reabsorbed into the vasa recta. The ascending limb of the loop of Henle is permeable to salt but not water; therefore, salt is reabsorbed both passively and actively. It has a diluting segment in the outer medulla; because salt is actively reabsorbed in this site, the filtrate actually becomes hypotonic compacted to the blood. At the beginning of the loop of Henle, the filtrate is isotonic to the interstitium. Thus from the beginning to the end of the loop of Henle, there is a slight degree of dilution. Far more important, however, is the fact that the volume of filtrate has been significantly reduced, demonstrating a net reabsorption of a large volume of water.
What is the pH of a solution containing 5mM H2SO4?
First convert the concentration to 5E-3 M. Next, because sulfuric acid is a strong acid, we can assume that, for the majority of sulfuric acid molecules (Although not all), both protons will dissociate. The concentration of hydrogen ions is therefore 2 x 5E-3, or 10-2. The equation for pH is pH= - log [H+]. If [H+] = 10^-2 M, then pH = 2.
Describe the process for converting a number into scientific notation. What value are possible for the significand.
First determine which digits are significant, as these will be preserved in scientific notation. Then, move the decimal point until the significand is greater than or equal to 1 and less than 10. Finally, determine what power of 10 is necessary for multiplication to restore the original number.
What's the order of the phosphates connected to the ribose in ATP?
First is the alpha phosphate directly attached to the ribose, then is the beta-phosphate, and last is the gamma-phosphate. Phosphoryl transfer from kinases comes from the gamma- phosphate of ATP.
What is the Henderson-Hasselbalch equation for weak acid buffer solutions?
For a weak acid buffer solution: pH = pKa + log [A-]/[HA] *where [A-] is the concentration of the conjugate base and [HA] is the concentration of the weak acid. Note that when [conjugate base] = [weak acid], the pH=pKa because log(1)=0. This occurs at the half-equivalence points in titration and buffering capacity is optimal at this pH.
What is the Henderson-Hasselbalch equation for weak base buffer solutions?
For a weak base buffer solution: pOH= pKb + log [B+]/[BOH] (*where [B+] is the concentration of the conjugate acid and [BOH] is the concentration of the weak base.) Note that when [conjugate acid] = [weak base], the pH=pKa because log(1)=0. This occurs at the half-equivalence points in titration and buffering capacity is optimal at this pOH.
Describe the focal length and radii of curvature for lenses.
For both mirrors and lenses, converging species have positive focal lengths and radii of curvature, and diverging species have negative focal lengths and radii of curvature. Remember that lenses have two focal lengths and two radii of curvature because they have two surfaces. For a thin lens where thickness is negligible, the sign of the focal length and radius of curvature are given based on the first surface light passes through.
What is Newton's third law?
For every action there is an equal and opposite reaction. If an object exerts a force x on another object, then the object being acted on will exert force x back: FAB= -FBA
What is Pascal's Principle
For fluids that are incompressible, pressure applied to a fluid is distributed undiminished throughout the entire volume of the fluid. Thus when it comes to hydraulic pistons: P= F1/A1= F2/A2 F2= F1 (A2/A1)
What does a positive focal length mean? A negative?
For mirrors, a positive focal length means that the mirror is concave (converging). For lenses this means that the lens is convex (converging). For mirrors, a negative focal length means that the mirror is convex (diverging). For lenses this means that the lens is concave (diverging).
What does a positive radius of curvature mean? A negative?
For mirrors, a positive radius of curvature means that the mirror is concave (converging). For lenses this means that the lens is convex (converging). For mirrors, a negative radius of curvature means that the mirror is convex (diverging). For lenses this means that the lens is concave (diverging).
Strong, soluble bases such as alkaline earth metal hydroxides are not used as antacids, but are often used in laboratory titrations. What volume of an aqueous 1.5 M Ba(OH)2 solution would be required to neutralize 10 mL of stomach acid (0.15 N HCl).
For neutralization to occur, the number of equivalents of base must be the same as the number of equivalents of acid. 0.15N HCl corresponds to 0.15 M HCl since it is a monoprotic acid. The number of moles of H+ contained in 10mL of stomach acid is therefore: 0.15 mol/ L * 0.010 L = 1.5E-3 mol THis is the number of moles of hydroxide ions, OH-, needed to neutralze the acid. Each mole of base used, Ba(OH)2, can give up two moles of hydroxide ions upon dissociation, and so a 1.5 M solution of the base has a normality of 3.0N,, i.e., the molarity of hydrozide ions is twice the nominal value given for Ba(OH)2. The volime of the base solution that would yield 1.5E-3 mol of OH- is: 3.0 mol/L * (V) = 1.5E-3 mol V= 1.5E-3/ 3.0mol/L = 0.5E-3 L = 0.5 mL
Experimenters isolate a biological sample believed to be composed entirely of glycine. In order to confirm their belief, they can hydrolyze the peptide and then: A: use separation techniques to determine if the sample contains amino acids with hydrophobic R groups. B: use polarized light in order to determine whether or not the sample is optically active. C. raise the pH of the sample and apply an electric field to test for the presence of zwitterions D. titrate the sample with NaOH to determine if it contains amino acids with acidic R groups.
Glycine is the only amino acid that has o chiral center as its R-group is simply a hydrogen atom. Therefore, a sample of pure glycine will not be optically active. The method described in choice B would help determine whether the protein contains any amino acids apart from glycine because as the passage states, most biological systems use only L-amino acids. Choice A is wrong because glycine would not have hydrophobic R groups, but neither would many other amino acids. Choice C is wrong because glycine along with all other neutral amino acids are zwitterions, and so there would be no difference to test. Also, the procedure described is an incomplete test for zwitterions. Choice D is wrong because glycine would not have an acidic R-group, but neither would many other amino acids.
Describe cyanohydrins
HCN has both triple bonds and an electronegative nitrogen atom, rendering it relatively acidic with a pKa of 9.2. After the hydrogen dissociates, the nucleophilic cyanide anion can attack the carbonyl carbon atom. Reactions with aldehydes and ketones produce stable compounds called cyanohydrins once the oxygen has been reprotonated. The cyanohydrin gains its stability from the newly formed C-C bond.
What's Hess's law?
Hess's law states that the total change in potential energy of a system is equal to the changes
An electrolytic cell is filled with water. Which of the following will move toward the cathode of such a cell? I. H+ ions II. O2- ions III. Electrons
I and III only In an electrolytic cell, ionic compounds are broken up into their constituents; the cations (positively charged ions) migrate toward the cathode, and the anions (negatively charged ions) migrate toward the anode. In this case, the cations are H+ ions (protons), so option I is correct. Electrons flow from anode to cathode in all types of cells, meaning that option II is also correct. Option II is incorrect for two reasons. First, it is unlikely that the anions in any cell would be O2- rather than OH-. Second, and more significantly, these anions would flow to the anode, not the cathode.
How do periodic forces affect waves?
If a periodically varying force is applied to a system, the system will then be driven at a frequency equal to the frequency of the force. This is known as forced oscillation. If the frequency of the applied force is close to that of the natural frequency of the system, then the amplitude of oscillation becomes much larger. This can be easily demonstrated by a child on a swing being pushed by a parent. If the parent pushes the child at a frequency nearly equal to the frequency at which the child swings back toward the parent, the arc of the swinging child will become larger and larger: the amplitude is increasing because the force-frequency is nearly identical to the swing's natural frequency. At this point, the system is said to be resonating.
Describe traveling waves
If a string fixed at one end is moved up and down, a wave will form and travel or propagate, toward the fixed end. Because this wave is moving, it is called a traveling wave (all the points in the wave are moving). If the free end of the string is continuously moved up and down there will then be two waves: the original wave moving down the string toward the fixed end and the reflected wave moving away from the fixed end. These waves will interfere with each other. Note: traveling waves have nodes and antinodes that move with wave propagation while standing waves have defined nodes and antinodes that do not move with wave propogation
In regards to spherical mirrors, what does image distance tell us?
If the image has a positive distance (i>0), it is a real image, which implies that the image is in front of the mirror. If the image has a negative distance (i<0), it is virtual and thus located behind the mirror.
How do we approximate logarithms?
If the nonlogarithmic value is written in proper scientific notation, it will ne in the form n x 10^-m, where n is a number between 1 and 10 . Taking the negative logarithm and simplifying the p value will be: -log (n x 10^-m) = -log(n) - log (10^-m) =m - log (n) p value ≈ m- 0.n
Looking at the formula ∆G°rxn= RT ln Q/Keq, what does Q/Keq tell us?
If the ratio of Q/Keq is less than one (Q<Keq) then the natural logarithm will be negative and the free energy change will be negative so the reaction will spontaneously proceed forward until equilibrium is reached. If the ratio of Q/Keq is greater than one (Q>Keq), then the natural logarithm will be positive and the free energy change will be positive. In this cases the reaction will spontaneously move in the reverse direction until equilibrium is reached. If the ratio is equal to 1. the reaction quotient is equal to the equilibrium constant and thus the reaction is at equilibrium and the free energy change is zero (ln 1 = 0).
How does piloerection prevent heat loss?
In cold conditions, arrector pili muscles contract, causing the hairs of the skin to stand up on end (piloerection). This helps to trap a layer of heated air near the skin.
What is the collision theory of chemical kinetics?
In order for a reaction to occur, molecules must collide with each other. The collision theory of chemical kinetics states that the rate of a reaction is proportional to the number of collisions per second between the reacting molecules. The theory suggests, however, that not all collisions result in a chemical reaction. An effective collision(one that leads to the formation of products) occurs only if the molecules collide with each other in the correct orientation and with sufficient energy to break their existing bonds and form new ones. ONly a fraction of colliding particles have enough kinetic energy to exceed the activation energy--this means that only a fraction of all collisions are effective.
fission reactions can be initiated by bombarding nuclei with neutrons. Could fission reactions be initiated by bombarding with protons instead? A. Yes, because protons and neutrons are both present in the nucleus B. Yes, because protons and neutrons have approximately the same mass C. No, because protons do not have as high a binding energy as neutrons and thus not as energetic D. No, because neutrons, unlike protons, do not experience electrostatic repulsion from the nucleus.
In order o fission to occur, energy must be supplied to the nucleus to initiate the reaction. This energy comes from the kinetic energy of the particle that is used to bombard the nucleus. In order for this kinetic energy to be transferred o the nucleus, the particle must be able to get within close proximity to it. Protons would not work well because being positively charged themselves, they would experience repulsion from the positively charged nucleus.
Describe reabsorption in regards to the kidneys
In the kidneys, some compounds that are filtered or secreted may be taken back up for use via reabsorption. Certain substances are almost always reabsorbed, such as glucose, amino acids, and vitamins. In addition, hormones such as antidiuretic hormone (ADH or vasopressin) and aldosterone can alter the quantity of water reabsorbed within the kidney in order to maintain blood pressure.
How does flow in the venae cavae relate to flow in the main pulmonary artery?
In theory, there should be equal flow in the venae cavae and the main pulmonary trunk. In reality, the flow in the vena cavae is slightly loess than in the pulmonary trunk because some of the blood entering the right side of the heart is actually from cardiac (coronary) circulation, not systemic circulation.
Describe the Tip to tail method of vector addition
In this method, the tail of B is placed at the tip of A without changing either the length or the direction of either arrow, In this tip-to-tail method the lengths of the arrows must be proportional to the magnitudes of the vectors. The vector sum A+B is the vector joining the tail of A to the tip of B
Describe isolated systems
Isolated systems are systems that are not capable of exchanging matter with their surroundings. As a result, the total change in internal energy must be zero.
what is the dopler effect
It describes the difference between the actual frequency of a sound and its perceived frequency when the source of the sound and the sound's detector are moving relative to one another--like how the siren of an ambulance truck is high in pitch as it approaches but then the pitch drops as it passes. That said, if the source and the detector are moving toward each other, the perceived frequency, f¹, is greater than the actual frequency, f. If the source and detector are moving away from each other, the perceived frequency is less than the actual frequency.
Describe the countercurrent multiplier system
It has to do with the fact that the flow of filtrate through the loop of Henle is in the opposite direction from the flow of blood through the vasa recta.
Describe the bomb calorimeter
It is a decomposition vessel that partakes in constant-volume calorimetry: A sample of matter, typically a hydrocarbon is placed in the steel decompisition vessel which is then filled with almost pure oxygen gas. The decomposition vessel is then placed in an insulated container holding a known mass of water. The contents of the decomposition vessel are ignited by an electric ignition mechanism. The material combusts (burns) in the presence of oxygen, and the heat that evolves is the heat of the combustion reaction. BEcause W= P∆V, no work is done in an isovolumetric process (∆V=0), so Wccalorimeter=0. Furthermore, because of the insulation, the whole calorimeter can be considered isolated from the ready of the universe, so we can identify the system as the sample plus the oxygen and the steel vessel, and the surroundings as the water. Because no heat is exchanged between the calorimeter and the rest of the universe, Qcalorimeter is 0.
Describe Red litmus paper
It is a pH indicator that stays red for acids and turns blue for bases
Describe Michael Addition
It is a reaction in which a 1,2-dicarbonyl reacts with strong base forming an enolate. The carbanion of the enolate then attacks an alpha,beta-unsaturated carbonyl compound --a molecule with a multiple bond between the alpha- and beta- carbons next to a carbonyl. The reaction proceeds due to resonance stabilization.
Describe the coffee calorimeter
It is an example of a constant-pressure calorimeter. It is an insulated container covered with a lid and filled with a solution in which a reaction or some physical process, such as dissolution, is occurring. The incident pressure, which is atmospheric pressure remains constant throughout the process and the temperature can be measured as the reaction progresses. There should be sufficient thermal insulation (such as styrofoam) to ensure that the heat being measured is an accurate representation of the reaction, without gain or loss of heat to the environment.
What is the formula for the maximum energy of an ejected electron?
Kmax= hf - W *where W is the work function of the metal in question--the work function is the minimum energy required to eject an electron and is related to the threshold frequency of that metal The formulas solve for the maximum kinetic energy of the electrons rather than exact kinetic energy because the actual energy can be anywhere between 0 and Kmax, depending on the specific subatomic interactions between the photon and the metal atom.
What is Ksp and how is it calculated?
Ksp is the solubility product constant, it is an equilibrium constant (a specialized verson of Keq): Ksp= [A^n+]^m[B^m-]^n *remember that pure solids and liquids do not appear in the equilibrium constant
If you see a sparingly soluble salt with the formula MX₃ what is the Ksp?
Ksp= 27x⁴ (assuming no common ion effect)
What is the formula for the ion product concentration? How is it sused?
Ksp= [A^n+]^m[B^m-]^n If a solution's IP is < its Ksp, then equilibrium has not yet been reached and the solution is unsaturated. If a solution's IP is > its Ksp, then the solution is beyond its equilibrium and considered supersaturated. If the IP = Ksp, the solution is at equilibrium and said to be saturated.
What is the formula for normality to molarity
Molarity= Normality/ n *where n is the number of protons, hydroxide ions, electrons, or ions produced or consumed by the solute (in acid base chemistry you're looking at either H+ or OH-)
Why is molecular nitrogen (N2) so unreactive?
Molecular nitrogen is normally a very unreactive molecule, because of the very strong triple bond holding the nitrogen atoms together
What is the formula for determining moles?
Moles= mass of sample (g)/ molar mass (g/mol)
Describe filtration of the kidneys
Occurs at bowman's capsule, the blood is filtered & collected fluid is known as the filtrate- similar to the composition of blood (water, salts, glucose & urea). The movement of the fluid into Bowman's space is governed by Starling forces, which account for the pressure differentials in both hydrostatic and oncotic pressure between the blood and Bowman's space. The hydrostatic pressure in the glomerulus is significantly higher than that in Bowman's space, which causes fluid to move into the nephron. On the other hand, the osmolarity of blood is higher than that of Bowman's space, resulting in pressure opposing the movement f fluid into the nephron. However the hydrostatic pressure is much larger than the oncotic pressure, so the net flow is still from the blood into the nephron. Urea: waste product of the body, formed in order to eliminate very toxic ammonia products
Describe the photoelectric effect
Occurs when lights of a sufficiently high frequency (typically, blue to ultraviolet light) is incident on a metal in a vacuum; it causes the metal atoms to emit electrons. Electrons liberated from the metal by the photoelectric effect will produce a net charge flow per unit time, or current. Provided that the light beam's frequency is above the threshold frequency of the metal, light beams of greater intensity produce larger current in this way. Thus, the photoelectric response is, for all intents and purposes, an "all or nothing" response: if the frequency of the incident photon is less than the threshold frequency (f <fT), then no electron will be ejected because the photons do not have sufficient energy to dislodge the electron from the atom.
How do decibels increase?
On the decibel scale, the level increase of 10 means that a sound is actually 10 times more intense, or powerful. So in terms of 20 dB vs 80 dB, the 80 dB sound is 10^6 times more intense than 20 dB.
What is the formula for the change in Gibbs free energy given Keq?
Once a reaction proceeds, it is no longer at standard state so we don't calculate ∆G°rxn for it: ∆Grxn= ∆G°rxn + RTln Q = RT ln Q/Keq
What is the 0th law of thermodynamics?
Once both objects reach equilibrium (the same temperature) there is no more movement of thermal energy. Thus, when one object is in thermal equilibrium with another object, and the second object is in thermal equilibrium with a third object, then the first and third object are also in thermal equilibrium. (If a=b and b=c then a also = c).
What is the perpendicular bisector of the dipole? What is unique about it?
Pertains to dipoles: An equipotential line that lies halfway between +q and -q. Because the angle between this plane and the dipole axis is 90degrees( and cos 90degrees=0), the electric potential at any point along this plane is 0. The magnitude of the electric field on the perpendicular bisector of the dipole can be approximated as: E= (1/ (4πε₀)) * p/r³
What is the order of polarity of functional groups
Phosphate > Amino = Carboxyl > Hydroxyl > Carbonyl > Sulfhydryl > Methyl (the H+ add polarity so that CH3BR is more polar than CBR)
What are the formulas for sine, cosine, and tan?
SOH CAH TOA sinθ = opposite/hypotenuse = a/c cosθ = adjacent/hypotenuse = b/c tanθ = opposite/adjacent = a/b
Which single bond present in nitroglycerin is most likely the shortest? A. C-H B. C-O C. C-C D. O-N
Solution: The correct answer is A. All of the bonds listed are single bonds. Since hydrogen has a much smaller atomic radius than second period elements, the covalent bond between C and H is shorter than any of the other bonds listed.
Describe ions as electrolytes
Solid ionic compounds tend to be poor conductors of electricity because the charged particles are rigidly set in place by the lattice arrangement of the crystalline solid. In aqueous solutions, however, the lattice arrangement is disrupted by the ion-dipole interactions between the ionic components and the water molecules. The cations and anions are now free to move, and as a result the solution of ions is able to conduct electricity.
Which of the following bases is the weakest? KOH NH3 CH3NH2 Ca(OH)2
Soluble hydroxides of Group IA and IIA metals are strong bases, eliminating (A) and (D). (B) and (C) are both weak bases; however, methylamine contains an alkyl group, which is electro-donating. This increases the electron density on the nitrogen in methylamine, making it a stronger (Lewis) base. Therefore, ammonia is the weakest base.
A student has a thin copper beaker containing 100 g of a pure metal in the solid state. The metal is at 215°C, its exact melting temperature. If the student lights a Bunsen burner and holds it for a fraction of a second under the beaker, what will happen to the metal? A. A small amount of the metal will turn to liquid, with the temperature remaining the same. B. All the metal will turn to liquid, with the temperature remaining the same. C. The temperature of the metal at the top of the beaker will increase. D. The temperature of the whole mass of the metal will increase slightly.
Solution: The correct answer is A. Melting occurs at a constant temperature because a certain amount of energy, the latent heat of fusion, is needed to convert a substance from its solid to liquid state. The temperature of the metal will not increase above its melting point until all of the metal has melted. The small amount of heat supplied by the bunsen burner is insufficient to melt 100 g of the metal but could melt a small amount of the metal at the constant temperature of the melting point. Thus, answer choice A is the best answer.
Assume that the side of the water tank is punctured 5.0 m below the top of the water, and that atmospheric pressure is 1.0 × 105 N/m2. What is the approximate speed of the water flowing from the hole? A. 10 m/s B. 12 m/s C. 14 m/s D. 17 m/s
Solution: The correct answer is A. The examinee must calculate the speed of water exiting a small puncture in the side of the tank 5.0 m below the surface of the water. The passage provides the equation needed, Bernoulli's equation: P2 + ½ ρv22 + ρgy2 = P1 + ½ ρv12 + ρgy1. Take point 2 to be at the location of the puncture and point 1 to be at the upper surface of the fluid. At point 1 above the fluid the pressure P1 is the atmospheric pressure and at point 2 outside the puncture the pressure P2 is also atmospheric pressure, so these terms cancel in Bernoulli's equation for this situation. Also note that the speed of water exiting the small puncture will be much larger than the speed of the upper water level falling at point 1. Thus, v2 >>v1 and v1 may be ignored. Canceling the pressures and setting v1 = 0 leaves the approximate result: ½ ρv22 + ρgy2 = ρgy1, which may be solved to yield v2 = [2g(y1 - y2)]1/2. The examinee is given that the height difference y1 - y2 is 5.0 m, hence, v2 = [2 (9.8 m/s2) (5.0 m)]1/2 = [98 m2/s2]1/2 ≈ 10 m/s. Thus, A is the best answer.
A charged particle with a mass of m and a charge of q is injected midway between the plates of a capacitor that has a uniform electric field of E. What is the acceleration of this particle due to the electric field? A. Eq/m B. Em/q C. mq/E D. Emq
Solution: The correct answer is A. The force on the charge is qE and force is also ma. Setting qE = ma and solving for acceleration a yields a= Eq/m Thus, A is the best answer.
When 2.0 mL of 0.1 M NaOH(aq) is added to 100 mL of a solution containing 0.1 M HClO(aq) and 0.1 M NaClO(aq), what type of change in the pH of the solution takes place?
Solution: The correct answer is A. The pH will increase because a strong base is added. The increase will be small because the base is being added to a buffer solution. Thus, A is the best answer.
If sounds produced by the human vocal cords are approximated as waves on a string fixed at both ends, and the average length of a vocal cord is 15 mm, what is the fundamental frequency of the sound? (Note: Use 3 m/s for the speed of sound through the vocal cord.) A. 10 Hz B. 100 Hz C. 1000 Hz D. 10,000 Hz
Solution: The correct answer is B. A. This incorrect answer results from using the length of the vocal cords as 15 cm. B. This question requires you to apply knowledge of sound production by vibrating cords and strings, and to identify the physical properties of such cords and their relationship with sound characteristics: frequency, propagation speed, and amplitude. In particular, the relationship between the sound speed and frequency for a string fixed at both ends must be used. The fundamental frequency of a vibrating string is given by f = v/(2L) = (3 m/s)/(30 × 10-3 m) = 1/10-2 Hz = 100 Hz. C. This incorrect answer results from using the sound speed as 30 m/s. D. This incorrect answer results from using the length of the vocal cords as 1.5 mm and the sound speed as 30 m/s.
If the speed of the charged particle described in the passage is increased by a factor of 2, the electrical force on the particle will: A. decrease by a factor of 2. B. remain the same. C. increase by a factor of 2. D. increase by a factor of 4.
Solution: The correct answer is B. Electrical force depends on the particle's charge and the strength of the electric field experienced by the particle, not on the particle's speed. Thus, B is the best answer.
Each of the following equations shows the dissociation of an acid in water. Which of the reactions occurs to the LEAST extent? A. HCl + H2O → H3O+ + Cl− B. HPO42− + H2O → H3O+ + PO43− C. H2SO4 + H2O → H3O+ + HSO4− D. H3PO4 + H2O → H3O+ + H2PO4
Solution: The correct answer is B. HPO42− has a high negative charge and so dissociation of it will occur to the least extent.
How will the rate of a catalyzed reaction be affected if the solid catalyst is finely ground before it is added to the reaction mixture? A.The rate will be faster because a greater mass of catalyst will be present. B.The rate will be faster because a greater surface area of catalyst will be exposed. C.The rate will be slower because the fine catalyst particles will interfere with product formation. D.The rate will remain the same because the mass of catalyst will be the same.
Solution: The correct answer is B. The answer to this question is B because grinding a heterogeneous catalyst increases the amount of catalyst available to the reaction (by increasing surface area) and therefore increases its rate.
An object O is at a distance of three focal lengths from the center of a convex lens. What is the ratio of the height of the image to the height of the object? A. 1/3 B. 1/2 C. 2/3 D. 3/2
Solution: The correct answer is B. The answer to this question is B because the ratio of the image height to the object height is equal to the ratio of the lens-image distance to the object-lens distance. According to the thin lens equation, the distance between the lens and the image is 3F x 1F/(3F - 1F) = (3/2)F, where F is the focal length. The ratio sought is then equal to (3/2)F/(3F) = 1/2.
An astronaut on Earth notes that in her soft drink an ice cube floats with 9/10 of its volume submerged. If she were instead in a lunar module parked on the Moon where the gravitation force is 1/6 that of Earth, the ice in the same soft drink would float: A. with more than 9/10 submerged. B. with 9/10 submerged. C. with 6/10 submerged. D. totally submerged.
Solution: The correct answer is B. The floating ice cube implies that its weight is balanced by the buoyant force on it Wice = mg = rfluid*Vsubmerged*g Note that both the weight and the buoyant force are proportional to g, making the numerical value of g irrelevant to the volume of the ice cube that is submerged. Thus, B is the best answer.
To a first approximation, the ionization constant of the weak acid H2S is: A. Less than zero. B. Between zero and one but close to zero. C. Between zero and one but close to one. D. Greater than one.
Solution: The correct answer is B. H2S was described as being a weak acid. This means that a small fraction of the solute molecule ionize and release protons into solution. The value of the ionization constant is therefore somewhere between 0 and 1, but much closer to 0. As an example, phosphoric acid, among the strongest of the weak acids, has an ionization constant that is approximately 1 x 10^-2, or 0.01. This is much closer to 0 than 1.
Suppose that CH4(g) reacts completely with O2(g) to form CO2(g) and H2O(g) with a total pressure of 1.2 torr. What is the partial pressure of H2O(g)? A. 0.4 torr B. 0.6 torr C. 0.8 torr D. 1.2 torr
Solution: The correct answer is C. The balanced equation for the complete combustion of CH4(g) is shown below. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) The pressure of the gaseous products is 1.2 torr. For every three product molecules, two are water. Therefore, the partial pressure of water is 2/3 the total pressure, because the total pressure is a function of the total number but not kind of molecules. Two-thirds of 1.2 torr is 0.8 torr. Thus, answer choice C is the best answer. Alternate solution: The total pressure is Ptotal = PCO2 + PH2O. Stoichiometrically, the number of moles of CO2 formed is one-half the number of moles of H2O formed. The partial pressure of each gas depends only on the number of moles. Then, PCO2 = (0.5)PH2O, and Ptotal = (0.5)PH2O + PH2O = (1.5)PH2O = 1.2 torr, or PH2O = 0.8 torr. Thus, answer choice C is the best answer
Which of the following best describes the movement of an electron after it is ejected from the cathode? A. It is stationary until collisions propel it toward the anode. B. It moves with constant speed toward the anode. C. It accelerates toward the anode. D. It exits through a side of the vacuum photodiode.
Solution: The correct answer is C. A charged particle accelerates in an electric field. The electron starts with a velocity that increases as it approaches the anode through the vacuum.
Which of the following statements most accurately describes the solubility properties of fatty acid salts? A. They are soluble in polar media only B. They are soluble in nonpolar media only C. They can partially dissolve in both polar and nonpolar media D. They are completely insoluble in both polar and nonpolar media
Solution: The correct answer is C. A fatty acid salt contains a long hydrocarbon chain, which is soluble in nonpolar solvents. The salt also contains the charged group -CO2-Na+, which is soluble in polar solvents. Thus, C is the best answer.
Which of the following shows the electron configuration of chlorine in NaCl? A. 1s²2s²2p⁶3s²3p⁴ B. 1s²2s²2p⁶3s²3p⁵ C. 1s²2s²2p⁶3s²3p⁶ D. 1s²2s²2p⁶3s²3p⁴4s²
Solution: The correct answer is C. In NaCl, chlorine exists as the chloride ion. A chloride ion has 18 electrons (it took one from Na ) with the electron configuration 1s²2s²2p⁶3s²3p⁶. Thus, C is the best
At pH 7, which of the following peptides will bind to an anion-exchange column and require the lowest concentration of NaCl for elution? A. AVDEKMSTRGHKNPG B. YPGRSMHEWDIKAQP C. HIPAGEATEKALRGD D. EAPDTSEGDLIPEVS
Solution: The correct answer is C. The answer is C because the anionic peptides bind to anion-exchange columns. The strength of the binding depends on the overall charge of the peptide. Of the options given, only C and D have a net negative charge. The net charge of peptide C is -1, whereas the net charge of peptide D is -5. Peptide C would elute at a lower salt concentration than Peptide D.
A tall tube is evacuated, and its stopcock closed. The open end of the tube is immersed into a container of water (density 103 kg/m3) that is open to the atmosphere (pressure 105 N/m2). When the stopcock is opened, how far up the tube will the water rise? A. 1 m B. 5 m C. 10 m D. 20 m
Solution: The correct answer is C. The answer to this question is C because the water will rise to a height such that the weight (mass multiplied by gravitational acceleration) of the water column equals the atmospheric pressure multiplied by the tube cross-sectional area A. Because mass is density times volume, it follows that 103 kg/m3 × h × A × 10 m/s2 = 105 N/m2 × A, where h is the height sought. Solving for h yields h = 105 N/m2/(104 N/m3) = 10 m.
An object that is totally immersed in benzene (specific gravity = 0.7) is subject to a buoyancy force of 5 N. When the same object is totally immersed in an unknown liquid, the buoyancy force is 12 N. What is the approximate specific gravity of the unknown liquid? A. 0.3 B. 0.9 C. 1.7 D. 2.3
Solution: The correct answer is C. The buoyant force on an immersed object is the product of: (density of the liquid) × (volume of the object) × (acceleration of gravity). Forming the ratio of buoyant forces in the two cases gives: 12/5 = (density of the unknown liquid)/(density of benzene, 0.7). Solving for the specific gravity of the unknown liquid, which is the ratio of its density to that of water, gives (12/5) × 0.7 = 1.7. Answer C is correct.
Consecutive resonances occur at wavelengths of 8 m and 4.8 m in an organ pipe closed at one end. What is the length of the organ pipe? (Note: Resonances occur at L = nλ/ 4, where L is the pipe length, λ is the wavelength, and n = 1, 3, 5,...) A. 3.2 m B. 4.8 m C. 6.0 m D. 8.0 m
Solution: The correct answer is C. The examinee is given two wavelengths (8 m and 4.8 m) that yield resonance in an organ pipe closed at one end. From this information the examinee must determine the length of the pipe. The question reminds the examinee that the resonant wavelengths λ are related to the length of this pipe via: L = nλ /4, where n = 1, 3, 5... Since n increases from n to n + 2 for two consecutive wavelengths one may write for the two given wavelengths, 4L = n(8 m) and 4L = (n + 2)(4.8 m). Equating the right sides of these two equations: n(8 m) = (n + 2)(4.8 m) which is easily solved to show that n = 3. Putting n = 3 into 4L = n(8 m) yields 4L = 24 m, so L = 6.0 m. Thus C is the best answer.
Ball 2 is in the water 20 cm above Ball 3. What is the approximate difference in pressure between the 2 balls? A. 2 × 102 N/m2 B. 5 × 102 N/m2 C. 2 × 103 N/m2 D. 5 × 103 N/m2
Solution: The correct answer is C. The examinee must determine the pressure difference between two locations in water at depths separated by 20 cm. The absolute pressure p at depth h below the surface of a fluid is: p = p0 + ρgh, where p0 is the atmospheric pressure above the liquid, ρ, is the density of the liquid, and g = 9.8 m/s2. Thus, the pressure difference Δp between two locations in the water would be Δp = ρgΔh, where Δh is the difference in depth. Here, Δh = 20 cm = 0.20 m. Thus, Δp = (1000 kg/m3)(9.8 m/s2)(0.20 m) = 1960 Pa = 2.0 x 103 Pa. Thus, C is the best answer.
Ca2+(aq) + 2HCO3-(aq) --> CaCO3(s) + CO2(g) + H2O(l) What is the concentration of Ca2+(aq) in a saturated solution of CaCO3? (Note: The solubility product constant Ksp for CaCO3 is 4.9 × 10-9.) A. 2.4 × 10-4 M B. 4.9 × 10-5 M C. 7.0 × 10-5 M D. 4.9 × 10-9 M
Solution: The correct answer is C. The solubility product constant expression for CaCO3 is Ksp = [Ca2+][CO3^2-]. Since equal quantities of Ca2+(aq) and CO3^2-(aq) are produced when CaCO3 dissolves, this expression reduces to 4.9E-9 = x^2, or 49E-10 = ^2. This can be solved directly by taking the square root of each side.
To determine a protein's thermodynamic stability, chemical denaturation studies can be performed. Assuming that only the native and unfolded states can be observed under experimentally available conditions, what is the most likely shape of the curve for the dependence of the fraction of folded protein upon denaturant concentration? A. Hyperbolic B. Linear C. Sigmoidal D. Exponential
Solution: The correct answer is C. This is correct. The answer is C because the unfolding of proteins is a cooperative process. Cooperative processes are marked by sigmoidal curves. *The protein will resist denaturation until a certain point, then it will denature. In other words, proteins denature cooperatively.
4C3H5N3O9(l) → 12CO2(g) + 10H2O(g) + 6N2(g) + O2(g) At STP, the volume of N2(g) produced by the complete decomposition of 1 mole of nitroglycerin would be closest to which of the following? A. 5 L B. 10 L C. 20 L D. 30 L
Solution: The correct answer is D. Based on the balanced equation provided, 4 moles of nitroglycerin produce 6 moles of N2(g). Therefore, 1 mole of nitroglycerin will produce 1.5 moles of N2(g). At STP 1.5 moles of N2(g) will occupy 33.6 L since the molar volume of an ideal gas at STP is 22.4 L/mol.
What are the oxidizing and reducing agents, respectively, in the reaction below? 2HCl + H2O2 + MnO2 → O2 + MnCl2 + 2H2O
Solution: The correct answer is D. In the reaction pictured, Mn is reduced from +4 to +2; therefore, MnO2 is the oxidizing agent. O is oxidized from -1 in H2O2 to 0 in O2; therefore, H2O2 is the reducing agent. Thus, D is the best answer.
A common column material used in size-exclusion chromatography is dextran, a polysaccharide of glucose. Which type of interaction most likely occurs between proteins and the dextran column material? A. Aromatic B. Hydrophobic C. Salt bridge D. Hydrogen bonding
Solution: The correct answer is D. The answer to this question is D because a polysaccharide of glucose has numerous hydroxyl groups that can hydrogen bond to the polar side chains that are typically exposed on a protein surface.
The energy of activation for the reaction described in the passage is given by the energy of: A. the reactants minus the energy of the products. B. the products minus the energy of the reactants. C. the activated complex minus the energy of the products. D. the activated complex minus the energy of the reactants.
Solution: The correct answer is D. The answer to this question is D because the activation energy for a reaction represents the minimum energy barrier necessary to be overcome by the reactants on the path to products. D is correct because it is telling us how much energy was required to get to the top of the hill so that the reaction could proceed downhill. B is incorrect because that gives us Gibb's free energy.
Which of the following energy conversions best describes what takes place in a battery-powered resistive circuit when the current is flowing? A. Electric to thermal to chemical B. Chemical to thermal to electric C. Electric to chemical to thermal D. Chemical to electric to thermal
Solution: The correct answer is D. The answer to this question is D because the chemical energy of the battery elements is used as electrical energy to set the charge carriers in motion through the resistor, where they experience drag from the crystal lattice of the resistive conductor and dissipate their energy as heat from the resistor.
Males 66-70 yo wear glasses with a focal length of -50. What kind of image is formed by the lenses of the glasses worn by a 68-year-old male who sees an object 2 m away? A. Real and enlarged B. Real and reduced C. Virtual and enlarged D. Virtual and reduced
Solution: The correct answer is D. The answer to this question is D because the lenses have a negative focal length which means they are diverging lenses. Such lenses form virtual and reduced images of objects situated at distances larger than the focal length.
The relative thermodynamic stability of isomeric organic compounds can be inferred from which of the following types of experimental data? A. Boiling points B. UV-visible absorption spectra C. Mass spectroscopic fragmentation patterns D. Heats of combustion
Solution: The correct answer is D. The answer to this question is D because the relative thermodynamic stability of isomers can be determined based on the amount of heat produced when the compounds are combusted; less heat, greater stability.
Assume the hydrolysis of ATP proceeds with ΔG′° = -30 kJ/mol. ATP + H2O → ADP + Pi Which expression gives the ratio of ADP to ATP at equilibrium, if the [Pi] = 1.0 M? (Note: Use RT = 2.5 kJ/mol.) A. e^2 B. e^3 C. e^6 D. e^12
Solution: The correct answer is D. The answer to this question is D. The free energy of the reaction ΔG′° is related to the equilibrium constant Keq = [ADP][Pi]/[ATP] as ΔG′° = -RTln(Keq). Applying [Pi] = 1 and using the expression for Keq gives ΔG′° = -RTln([ADP]/[ATP]), so that [ADP]/[ATP] = e^(30/2.5) = e^12.
The intensity level of Sound B is 20 dB greater than the intensity level of Sound A. How many times greater is the intensity level of Sound B than the intensity level of Sound A? A. 2 B. 10 C. 20 D. 100
Solution: The correct answer is D. The examinee is asked to compare the intensities of two sounds, given a comparison of their intensity levels in decibels, dB. The intensity level β in dB is defined by: β = 10Log(I/I0), where I is the intensity of the sound and I0 is the minimum intensity audible to the human ear. "Log" indicates the base 10 logarithm. Two sounds A and B would have intensity levels βA = 10Log(IA/I0) and βB = 10Log(IB/I0) which may be subtracted to yield: βB- βA = 10Log(IB/IA). The question states that βB is 20 dB larger than βA, hence βB- βA = 20 dB. Thus, 20 = 10Log(IB/IA) or Log(IB/IA) = 2. This yields IB/IA = 102 = 100. Thus D is the best answer.
Assume that the density of Ball 1 is 8.0 × 102 kg/m3. Ignoring the atmospheric pressure, what fraction of Ball 1 is above the surface of the water? A. 4/5 B. 3/4 C. 1/4 D. 1/5
Solution: The correct answer is D. The examinee must use the given density of water (ρ = 1000 kg/m3) and of ball 1 (D1 = 800 kg/m3) to determine the fraction of ball 1 above the surface of the water. As ball 1 floats, part of its volume is submerged. Call this volume VS. According to Archimedes' Principle (AP) the upward buoyant force, B, on the ball equals the weight of water displaced by the ball. The mass of displaced water would be ρVS, so the weight of displaced water would be ρVSg. Thus, according to AP we can write B = ρVSg. The ball floats, so its weight mg is balanced by the upward buoyant force, thus ρVSg = mg. The ball's mass is D1V, hence ρVSg = D1Vg which may be solved for the submerged volume: VS = (D1/ρ)V = (800/1000)V = 0.8V. This tells us that 0.8V is below the surface, thus V - 0.8V = 0.2V must be above the surface. The fraction of ball 1 above the surface is thus 2/10 = 1/5. Thus, D is the best answer.
Which of the following atoms has the largest first ionization energy? A. Potassium B. Zinc C. Gallium D. Krypton
Solution: The correct answer is D. The first ionization energy is the energy required to remove an electron from the outer shell of an atom. For any given period, it is lowest when the removal of the electron results in a complete shell or subshell, and highest when the removal of the electron disrupts a complete shell or subshell. Krypton, a noble gas, has a complete outer shell of electrons and therefore has an extremely high ionization energy. Potassium, with only one electron in its outermost shell, has a low ionization energy. Choice D is the correct answer.
A stationary receiver detects a change in frequency of the signal from a jet flying directly away from it at 300 m/s. Which of the following receivers will detect the same change in frequency from a jet moving away at 600 m/s? A. A receiver moving at 900 m/s in the opposite direction as the jet B. A receiver moving at 300 m/s in the opposite direction as the jet C. A stationary receiver D. A receiver moving at 300 m/s in the same direction as the jet
Solution: The correct answer is D. The frequency shift of the Doppler effect for radio waves depends on the relative motion of the source and detector. The condition that gives the same shift as the case of the stationary receiver with a moving jet is the one that has the same relative velocity between the receiver and jet, that is, the one in which the receiver moves in the same direction as the jet.
What is solvation?
Solvation is the electrostatic interaction between solute and solvent molecules. This is also known as dissolution, when water is the solvent it can be called hydration. Solvation involves breaking intermolecular interactions between solute molecules and between solvent molecules and forming new intermolecular interactions between solute and solvent molecules together. Note: when the new interactions are stronger than the original ones, solvation is exothermic, and the process is favored at low temperatures. When the new interactions are weaker than the original ones, solvation is endothermic and the process is favored at high temperatures.
What is dispersion?
Spreading of white light into ROYGBIV because each wavelength has its own index of refraction -- The speed of light in a vacuum is the same for all wavelengths. However, when light travels through a medium, different wavelengths travel at different speeds. This fact implies that the index of refraction of a medium affects the wavelength of light passing through the medium because the index of refraction is related to the speed of the wave by n= c/v. It also implies that the index of refraction itself actually varies with wavelength. Note: as light enters a medium with a different index of refraction, the wavelength changes but the frequency does not.
3 moles of N2O4 is placed in a 0.5 L container and allowed to reach equilibrium according to the following reaction: N2O4 (g) ↔ 2 NO2(g) What is the equilibrium concentration of NO2. given Keq for that reaction is 6E-6?
Start by writing the expression for Keq: Keq= [NO₂]² / [N₂O₄] Note that the concentration of NO₂ is squared due to its coefficient of 2 in the balanced reaction. Next, determine the starting concentration of N₂O₄, taking into account that the initial volume is 0.5L. 3M/0.5L= [N₂O₄]/1L [N₂O₄]= (3)(1)/ (0.50 = 6 M Thus the starting concentration of N₂O₄ = 6M. Next, using x to represent the amount of N₂O₄ that reacts, 2x to represent the amount of NO₂ that is produced, and 10^-6 for the value of Keq, plug into the expression for the equillibrium constant: Keq= 6E-6 = [2x]² / [6-x] ≈ [2x]² / [6] Note that the very small value of Keq indicates that x will be negligible in comparison to 6M, allowing the Keq expression to be simplified, and x to be determined as follows: 6E-6 = 4x² / 6 36E-6= 4x² x² = 36E-6/4 = 9E-6 x=3E-3 However, be careful to note that this is the value of x, which represents the amount of N₂O₄ that reacts. The final answer must represent the amount of NO₂ produced, which is twice the amount of N₂O₄ that reacts, or 2x. Thus the final answer is the concentration of NO₂, which is 6E-3 M.
Describe structural isomers
Structural isomers are the least similar of all isomers. In fact, the only thing that structural isomers (also called constitutional isomers) share is their molecular formula, meaning that their molecular weights MUST be the same. Aside from this similarity, structural isomers are widely varied, with different chemical and physical properties.
What is the formula for calculating torque on a dipole in an electric field?
T= pEsinθ *where p is the magnitude of the dipole moment (p=qd), E is the magnitude of the uniform external electric field, and θ is the angle the dipole moment makes with the electric field. Note: The torque will cause the dipole to reorient itself so that its dipole moment, p, aligns with the electric field E.
What is the formula for torque?
T=rFsin(θ) *where r is the length of the lever arm and
What is Tm?
Temperature where half the DNA is denatured. It is different for different DNA strands
What is the only necessity for Hill's criteria for causation?
Temporality: the exposure (independent variable) must occur before the outcome (dependent variable).
Hoe do charges move?
The "plus" end of a battery is the high-potential end, and the "minus" end of a battery is the low-potential end. Positive charge move from + to - (the definition of current) while negative charges move from - to +. Thus, positive charges will spontaneously move in the direction that decreases their electrical potential ( creating a negative voltage), whereas negative charges will spontaneously move in the direction that increases their electric potential (creating a positive voltage)-- yet in both cases, the electric potential is decreasing. (review page 166 of math and phys for any issues)
What is the Henderson-Hasselbalch equation?
The Henderson-Hasselbach equation is used to estimate the pH or pOH of a buffer solution. For a weak acid buffer solution: pH = pKa + log [A-]/[HA] (*where [A-] is the concentration of the conjugate base and [HA] is the concentration of the weak acid. ) For a weak base buffer solution: pOH= pKb + log [B+]/[BOH] (*where [B+] is the concentration of the conjugate acid and [BOH] is the concentration of the weak base.)
Describe the SN2 mechanism
The SN2 reaction first proceeds with inversion of configuration (stereochemistry). This is because it proceeds through a concerted backside attack of the nucleophile upon the alkyl halide --it's like an umbrella in a strong wind. As the C-nucleophile bond forms, the C- leaving group bond breaks. This reaction is slowed down the bulkier that a molecule is. Thus the SN2 reaction is more likely to occur in the least sterically hindered molecule.
How don the alpha hydrogens of ketones compare to that of aldehydes?
The alpha hydrogens of ketones tend to be slightly less acidic than those of aldehydes due to the electron-donating properties of the additional alkyl group in a ketone. This property is the same reason that alkyl groups help to stabilize carbocations -- but in this case, they destabilize the carbanion. Note: EWG like oxygen stabilize organic anions. EDG like alkyl groups destabilize organic anions.
What is specific heat?
The amount of heat energy required to raise one gram of a substance by one degree Celsius or one unit Kelvin. It involves the transfer of heat
What is the critical angle? How is it calculated?
The angle of incidence when the angle of refraction is 90 degrees. Thus: θc = sin-¹ (n₂/n₁)
How do we determine the oxidation of a monatomic ion?
The xidaiton of a monatomic on is equal to the charge of the ion. For example, the oxidation numbers for Na+, Cu2+, Fe3+, Cl-, and N3- are +1, +2, +3, -1, and -3, respectively.
What straight-chain conformation is the most stable?
The anti staggered conformation. This is when the largest groups of the molecule are oriented 180 degrees away from each other. In this position, there is minimal steric repulsion between the atom's electron clouds because they are as far apart as they can possibly be. Thus the atoms are "happiest" in their lowest energy state. Because there is no overlap of atoms along the line of sight (see Newman Projection), the molecule is said to be staggered conformation. Specifically, it is called the anti conformation because the two largest groups are antiperiplanar (in the same plane, but on opposite sides) to each other.
Describe the passage of urine
The bladder has a muscular lining known as the detrusor muscle. Parasympathetic activity causes the detrusor muscle to contract. However, in order to leave the body, urine must pass through two sphincters -- the internal and external urethral sphincters: *The internal urethral sphincter, consisting of smooth muscle, is contracted in its normal state. Because the internal sphincter is made of smooth muscle, it is under involuntary control. *The external sphincter consists of skeletal muscle and is under voluntary control. When the bladder is full, stretch receptors convert to the nervous system that the bladder requires emptying. This causes parasympathetic neurons to fire, and the detrusor muscle contracts. This contraction also causes the internal sphincter to relax. This reflex is known as the micturition reflex. The next step is up to the individual. The person can choose to relax the external sphincter to urinate or can maintain the tone of the external sphincter to prevent urination. Note: Urination itself is facilitated by the contraction of the abdominal musculature, which increases pressure within the abdominal cavity, resulting in compression of the bladder and increased urine flow rate
Two identical balloons of negligible mass are tethered at altitudes of 2000 meters and 2600 meters, respectively. The balloons are filled with helium gas to equal volumes. Which of the following statements is true concerning the buoyant force acting on each balloon? A. The buoyant force on the balloon at 2600 meters will be greater. B. The buoyant force on the balloon at 2000 meters will be greater. C. The buoyant forces on the two balloons will be equal. D. The relationship between the buoyant forces cannot be determined.
The buoyant force acting on an object is equal in magnitude to the weight of the fluid it displaces. Because the balloons are of equal volume, they displace an equal volume of fluid. Lower altitude air is more dense, and thus, a given volume will weigh more. The balloon at the lower altitude (2000 m) will have a greater buoyant force applied to it because the air is more dense at the lower altitude. Therefore choice B is correct
What is capacitance? How is it calculated in terms of charge and voltage?
The capacitance of a capacitor is defined as the ration of the magnitude of the charge stored on one plate to the potential difference (voltage) across the capacitor. Therefore, if a voltage V is applied to the plates of a capacitor and a charge Q collects on it (with +Q on the positive plate and -Q on the negative plate), then the capacitance is given by: C= Q/V *note that the SI unit for capacitance is the farad (1F = 1C/V)
Describe the charge of electrodes in electrochemical cells
The charge on an electrode is dependent on the type of electrochemical cell one is studying. *For galvanic cells, the anode is negatively charged and the cathode is positively charged. ( In a galvanic cell, the anode is negative) *For electrolytic cells, the anode is positively charged and the cathode is negatively charged. However, in both types of cells, reduction occurs at the cathode and oxidation occurs at the anode; cations are attracted to the cathode, and anions are attracted to the anode. Electrons always flow through the wire from anode to cathode and the current flows from cathode to anode.
What is the combined gas law? Write the equation
The combined gas law is a combination of Boyle's, Charles's, and Gay-Lussac's laws; it shows an inverse relationship between pressure and volume along with direct relationships between pressure and volume with temperature. P1V1/T1 = P2V2/T2
During study design, a company wishing to market a drug to severe diabetics proposes to enroll only mild diabetics. Which principle of research ethics is the company violating? Are there any research concerns in this proposed study besides ethics?
The company is violating the principle of justice by choosing participants that are not part of the target population. The company is also introducing selection bias.
What is true about parallel circuits?
The voltage drop is the same throughout the circuit. However, while the voltage is the same for all parallel pathways, the resistance of each pathway may differ. In this case, electrons prefer the path of least resistance; in other words, the current will be largest through the pathways with the lowest resistance.
Describe the dermis
The dermis consists of multiple layers: *The upper layer (right below the epidermis) is the papillary layer, which consists of loose connective tissue. *Below the papillary layer is the denser connective tissue of the reticular layer. Sweat glands, blood vessels, and hair follicles originate in the dermis. Most sensory receptors are also located in the dermis.
Measurements of the atomic mass of a neutron and a proton yield these results: proton = 1.00728 amu neutron= 1.00867 amu 4 , 2He contains two protons and two neutrons, which should theoretically give helium a mass of 2 * 1.00728 + 2 * 1.00867= 4.03190 amu. However, the true mass of the helium nucleus is 4.00260 amu. What is the mass defect and binding energy of this nucleus? (Note: c^2= 932 MeV/amu)
The difference 4.03190- 4.00260 = 0.02930 amu is the mass defect for the helium nucleus. This is the mass that contributed to the binding energy of the nucleus: E= mc^2 = (0.02930 amu)(932 MeV/amu) approx. = 0.03 * 900 = 27 MeV (actual= 27.3 MeV)
What is the electromotive force?
The difference in electric potential (voltage) that drives current in a circuit or battery. A potential difference (voltage) can be produced by an electrical generator, a galvanic cell (voltaic cell), a group of cells wired into a battery, or even a potato. When no charge is moving between the two terminals of a cell that are at different potential values, the voltage is called the electromotive force (emf or ε). Do not be misled by this term, as emf is not actually a force; it is a potential difference (voltage) and, as such, has units of joules per coulomb ( 1V = 1 J/C) -- not newtons. Note: It may be helpful to think of emf as a "pressure to move" that results in current, in much the same way that a pressure difference between two points in a fluid-filled tube causes the fluid to flow.
Why does a dipole have torque?
The dipole is a classic example of a setup upon which torques can act. In the absence of an electric field, the dipole axis can assume any random orientation. However, when the electric dipole is placed in a uniform electric field, each of the equal and opposite charges of the dipole will experience a force exerted on it by the field. Because the charges are equal and opposite, the forces acting on the charges will also be equal in magnitude and opposite in direction, resulting in a situation of translation equilibrium. However, there will be no rotational equilibrium. This is because the forces are in opposite directions (left and right), but the torques are in the same direction (clockwise for both).
What is the relationship between instantaneous velocity and friction?
The direction of frictional force always opposes movement. Once the instantaneous velocity vector is known (or net force in the case of static force), the frictional force has to be in the opposite direction
A block is fully submerged three inches below the surface of a fluid, but is not experiencing any acceleration. What can be said about displaced volume of fluid and the buoyant force?
The displaced volume is equal to the volume of the block. The buoyant force is equal to the weight of the block, and is equal to the weight of the displaced fluid. By extension, the block and the fluid in which it is immersed must have the same density.
What is the focal length?
The distance between the focal point and the mirror
How does change in electric potential energy differ depending on charge
The electric potential energy of a system will increase when two like charges move toward each other or when two opposite charges move apart. Conversely, the electric potential energy of a system will decrease when two like charges move apart or when two opposite charges move toward each other.
When placed one meter apart from each other, which will experience a greater acceleration: one coulomb of electrons or one coulomb of protons?
The electron swill experience the greater acceleration because they are subject to the same force as the protons but have a significantly smaller mass
What determines the absorption spectrum of a single atom?
The energy differences between the ground-state electrons and higher-level electron orbits determine the frequencies of light a particular material absorbs (the absorption spectrum).
Describe the epidermis
The epidermis is subdivided into layers called strata. From superficial inward, these are the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Come Let's Get Some Beers
Which of the following best expresses the algebraic relationship between molar solubility, x, of Ca3(PO4)2 and its solubility constant Ksp?
The expression asked for can be derived by setting up the equilibrium expression for the dissolution of calcium phosphate, which will produce 3 x moles of calcium ions and 2 x moles of phosphate for each x moles of calcium phosphate dissolved. Algebraically, we can rearrange t to solve for Ksp in terms of molar solubility: Ca₃(PO₄)₂ → 3 Ca²+ + 2PO₄³- Ksp= [Ca²+]³ [PO₄³-]² = (3x)³ (2x)² = (27x³)(4x²)= 108x⁵
How do we separate enantiomers?
The fact that enantiomers have identical physical and chemical properties prompts a question about racemic mixtures: how can one separate the mixture into its two constituent isomers? The answer lies in the relationship between enantiomers and diastereomers. Reacting two enantiomers with a single enantiomer of another compound will, by definition, lead to two diastereomers. Imagine, for example, two enantiomers that contain only one chiral carbon; these compounds could be labeled (+) and (-). If each is reacted with only the (+) enantiomer of another compound, two products will result: (+,+) and (-,+). Because these two products differ at some -- but not all-- chiral centers, they are necessarily diastereomers. Diastereomers have different physical properties. These differences enable one to separate these products by common laboratory techniques such as crystallization, filtration, distillation, and others. Once separated, these diastereomers can be reacted to regenerate the original enantiomers.
Describe the proximal convoluted tubule
The filtrate first enters the PCT. In this region, amino acids glucose, water-soluble vitamins, and the majority of salts are reabsorbed along with water. Almost 70 percent of filtered sodium will be reabsorbed here, but the filtrate remains isotonic to the interstitium as other solutes and a large volume of water are also reabsorbed. Solutes that enter the interstitium --the connective tissue surrounding the nephron --are picked up by the vase recta to be returned to the bloodstream for reuse within the body. The PCT is also the site of the secretion of a number of waste products, including hydrogen ions, potassium ions, ammonia, and urea.
Describe the colelcting duct of the nephron
The final concentration of the urine will depend largely on the permeability of the collecting duct, which is responsive to both aldosterone and antidiuretic hormone (ADH or vasopressin). AS permeability of the collecting duct increases, so too does water reabsorption, resulting in further concentration of the urine. The reabsorbed water enters the interstitium and makes its way to the vasa recta, where it reenters the bloodstream to once again become part of the plasma. The collecting duct almost always reabsorbs water but the amount is variable: -when the body is very well hydrated, the collecting duct will be fairly impermeable to salt and water -when in conservation mode, ADH and aldosterone will each act to increase reabsorption of water in the collecting duct, allowing for greater water retention and more concentrated urine output.
Suppose an individual with dry skin has come in contact with a high-voltage DC circuit. In an attempt to rescue the individual, another person, with wet skin, makes contact with the first, forming a parallel connection. Consequently, the amount of time required for 10 C of charge to exit the power source will: A. increase B. decrease C. remain the same D. There is not enough information to determine a change in current Explain the answer
The first person acts as a resistor. If a second person latches on to the first, he to would be a resistor- one that has been added in parallel. Moreover, the second person has wet skin, so will have a lower resistance. Adding resistors in parallel acts to decrease the overall resistance f a circuit. Therefore, if resistance decreases, total current passing through the circuit will increase. Since current is ∆q/∆t, an increase in current implies that less time will be required to pass the same amount of change,
In a solubility experiment, solutes X and Y are introduced into a subject's bloodstream. The solubility product constants of X and of Y are both determined to be greater than their solubility product constants at standard conditions. What is the most likely explanation for this? A. Common ion effect B. Effect of temperature C. Effect of blood pH D. Effect of saturation levels of plasma
The most likely reason for the increase in solubility is an increase in temperature, hence choice B is correct. Choices A and D are incorrect because the common ion effect will not affect the solubility product (it will affect the molar solubility) . C is incorrect because only temperature can change the Ksp (it's an equilibrium constant).
The following reaction has a Keq of 2.1E-7. Given an initial concentration for A equal to 0.1 M and an initial concentration of B equal to 0.2 M, what is the equilibrium concentration of C? Is the approximation that x is negligible valid for this calculation? A(aq) + B(aq) ↔ C(g) + D(s)
The first step in solving is to write the equation for Keq for the reaction: A(aq) + B(aq) ↔ C(g) + D(s) Keq= [C]/ [A][B] = 2.1E-7 Note that the equation for Keq does not include product D because D is a solid. Next, using the initial concentration s for A and B and x for the amount that has been reacted, plug into the equation for Keq: Keq= [C]/[A][B] = [x]/[0.1-x][0.2-x] Given that Keq= 2.1E-7, the concentrations of A and B are sufficiently large that x can be considered negligible in comparison to both. This allows the equation for Keq to be simplified and solved: Keq= 2.1E-7≈ [x]/[0.1][0.2] x= (2.1E-7)(0.1)(0.2)= 4.2E-9 The value of x=4.2E-9 is equal to both the equilibrium concentration of C and the amount of A and B that have reacted. The approximation that x is negligible compared to the initial concentrations of A and B is valid.
What happens when a ketone is reduced?
The ketone becomes an OH group
What is the sum of the protons, neutrons, and electrons in strontium-90?
The number of protons in the nucleus of an element is given by the atomic number. In a neutral atom, the number of electrons is equal to the number of protons. The number of neutrons can be found by subtracting the atomic number from the mass number. The atomic number of strontium (Sr) is 38; so the number of neutrons is 90 - 38 = 52. The sum of protons, neutrons, and electrons in strontium is 38 + 38 + 52 = 128. This value is given as answer choice C.
Which molecule shows up first in gas chromatography?
The one with the weakest bonds
What is the oxidation number of hydrogen?
The oxidation number for hydrogen is usually +1; however, its oxidation number is -1 in compounds with less electronegative elements (Groups IA and IIA_. Hydrogen is +1 in HCl, but -1 in NaH.
Do polar molecules have a higher or lower boiling point?
The polar substance always has the higher boiling point, indicating greater attractive forces between separate molecules, that is, larger intermolecular forces. This is because molecules with higher polarity have greater dispersion forces and therefore stronger dipole-dipole interactions.
Describe freezing point depression. What is the formula?
The presence of solute particles in a solution interferes with the formation of the lattice arrangement of solvent molecules associated with the solid state. Thus, a greater amount of energy is must be removed from the solution (resulting in a lower temperature_ in order for the solution to solidify. The formula for calculating the freezing point depression for a solution is: ΔTf = iKfm *where i is the van't Hoff factor, Kf is the proportionality constant, and m is the molality of the solution.
In statistics what is power? How is it calulated?
The probability of correctly rejecting a false null hypothesis ( reporting a difference between two populations when one actually exists). It is equal to 1-beta
In statistics what is beta?
The probability of making a type II error: false negative Betas are so timid that they won't say things are true even when they are.
What is the purpose of a salt bridge?
The purpose of the salt bridge is to exchange anions and cations to balance, or dissipate, newly generated charges. Dissipating the charge gradient permits the exchange of cations and anions without build-up of charge on each end (page 418). Note: electrolytic cells do not have salt bridges
Describe a salt bridge
The salt bridge contains an inert electrolyte, usually KCl or NH4NO3, which contains ions that will not react with the electrodes or with the ions in solution. As Cl- (or NO3-) diffuses to the anode where positively charged ions have been created from oxidation, the K+ (or NH4+) will diffuse to the cathode where negatively charged ions have been made from reduction. Note: electrolytic cells do not have salt bridges
What is "work function"?
The work function is the minimum energy required to eject an electron and is related to the threshold frequency of that metal by the formula: W= h*fT The work function describes the minimum amount of energy necessary to emit an electron. Any additional energy from a photon will be converted to excess kinetic energy during the photoelectric effect.
What does it mean if Q = Keq?
The reaction is in dynamic equilibrium. The reactants and products are present in equilibrium proportions. The forward and reverse rates of reaction are equal.
What is meant by a real image? What about a virtual one?
The real image is on the real side and the virtual image is on the virtual side. The real side is where light actually goes after interacting with the lens or mirror. For mirrors light is reflected and therefore stays in front of the mirror. Hence, for a mirror. the real side is in front of the mirror and the virtual side is behind the mirror. For lenses, the convention is different: because light travels through the lens and comes out on the other side, the real side is on the same side of the lens as the original light source.
How can we use the right hand rule to determine the direction of magnetic force on a current carrying wire?
The same as you do for a moving point charge: *Point your thumb in the direction of the velocity: this indicates the direction of movement, like a hitchhiker's thumb *Point your fingers in the direction of the magnetic field: these are the field lines. They are parallel like the uniform magnetic field lines. *Your palm is the force on a positive charge: you might give a "high five" to a positive person *The back of your hand is the force on the negative charge: you might backhand a negative person Th formula that relates to this is FB=qVBsin Just remember that current is considered the flow of positive charge!!!
Describe the stratum basale
The stratum basale is the deepest layer of skin. It contains skin cells and is responsible for proliferation of keratinocytes, the predominant cells of the skin, that produce keratin.
What is a dielectric material? What is its effect on capacitors?
The term dielectric material is just another way of saying insulation. When a dielectric material such as air, glass, plastic, ceramic, or certain metal oxides, is introduced between the plates of a capacitor, it increases the capacitance by a factor called the dielectric constant (κ). Thus, the dielectric constant of a material is a measure of its insulating ability.
What is the difference between a stationary test charge q and a stationary source charge Q
The test charge q is the charge placed in the electric field and the source charge Q is what actually creates the electric field
What is the half-life of a radioactive material?
The time it takes for half of all the radioactive nuclei to decay into their daughter nuclei, which may or mat not be radioactive
What is extraction?
The transfer of a dissolved compound (the desired product) from a starting solvent into a solvent in which the product is more soluble. Extraction is based on the fundamental concept that like dissolves like. Once the materials are separated a separatory tunnel can be use to isolate the layers. The densest layer will be on the bottom. Once the desired product has been isolated in the solvent, we can obtain the product alone by evaporating the solvent, usually using a rotary evaporator (rotovap).
What is radiation?
The transfer of energy by electromagnetic waves. Unlike conductions and convection, radiation can occur through a vacuum.
How do we multiply vectors by other vecctors?
This is done either to generate a third vector or a scalar: To generate a scalar like work, we multiply the magnitudes of the two vectors of interest (force and displacement) and the cosine of the angle between the two vectors. In vector calculus this is called the dot product (A * B): A*B= |A| |B| cosθ In contrast, when generating a third vector like torque, we need to determine both its magnitude and direction. To do so, we multiply the magnitudes of the two vectors of interest (force and lever arm) and the sine of the angle between the two vectors. Once we have the magnitude, we use the right-hand rule to determine its direction. In vector calculus, this is called the cross product (A x B): A x B = |A| |B| sinθ
Describe translational equilibrium
Translational equilibrium exists only when the vector sum of all of the forces acting on an object is zero. This is called the first condition of equilibrium, and it is merely a reiteration of Newton's first law. Remember that when the resultant force acting upon an object is zero, the object will not accelerate; that may mean that the object is stationary but could also just mean that the object is moving with a constant nonzero velocity. Thus an object experiencing translational equilibrium will have a constant velocity: both a constant speed (which could be zero or a nonzero value) and a constant direction.
What is translational motion?
Translational motion occurs when forces cause an object to move without any rotation. The simplest pathways may be linear, such as when a child slides down a snowy hill on a sled, or parabolic, as in the case of a cannonball shot out of a cannon.
Describe dielectrics in isolated capacitors
When a dielectric material is placed in an isolated, charged capacitor --that is, a charged capacitor disconnected from any circuit -- the voltage across the capacitor deceases. This is a result of the dielectric material shielding the opposite charges from each other. By lowering the voltage across a charged capacitor, the dielectric has increased the capacitance of the capacitor by a factor of the dielectric constant. Thus, when a dielectric material is introduced into an isolated capacitor, the increase in capacitance arises from a decrease in voltage.
How do we find the equilibrium constant for a reaction that occurs in more than one step?
When a reaction occurs in more than one step, the equilibrium constant for the overall reaction is found by multiplying together the equilibrium constants for each step of the reaction. When this sdone, the equilibrium constant for the overall reaction is equal to the concentrations of the products divided by the concentrations of the reactants in the overall reaction, with each concentration raised to the stoichiometric coefficient for the respective species. The forward and reverse rate constants for the nth step are designated kn and k-n, respectively. For example, if the reaction aA + bB ↔ cC +dD occurs in three steps, each each with a forward and reverse rate, then Kc= (k1k2k3)/ (k-1k-2k-3) = [C]^c[D]^d / [A]^a[B]^b
What is elastic potential energy? How is it calculated?
When a spring is stretched or compressed from its equilibrium length, the spring has elastic potential energy which can be determined by: UE= ½ kx² *where x is the magnitude of displacement from equilibrium
Describe the heat of transformation
When a substance is undergoing a phase change, such as from solid to liquid or liquid to gas, the heat that is added or removed from the system does not result in a change in temperature (phase changes occur at a constant temp). This is because phase changes are related to PE not KE.
How do we multiply vectors by scalars?
When a vector is multiplied by a scalar n, its direction will change. Its direction will be either parallel or antiparallel to its original direction. For example, if a vector A is multiplied by a scalar n, a new vector B is created such that B=nA. To find the magnitude of B, simply multiply the value of A by |n|, the absolute value of n. To find the direction, look at the sign of n. If it is positive, B and A face the same direction. If n is negative, then B points in the opposite direction of A.
Describe capacitors in series
When capacitors are connected in series, the total capacitance decreases in similar fashion to the decreases in resistance seen in parallel resistors. This because the capacitors must share the voltage drop in the loop and therefore cannot store as much charge. Functionally, a group of capacitors in series acts like one equivalent capacitor with a much larger distance between its plates (in fact, with a distance equal to those of each of the series capacitors added together). This increase in distance, as seen earlier, means a smaller capacitance. *Note that for capacitors in series, the total voltage is the sum of the individual voltages, just like resistors in series.
What causes torsional strain?
When cyclic molecules must assume conformations that have eclipsed or gauche interactions
Describe CrO3 in oxidation
When dissolved with dilute sulfuric acid in acetone, this is called the Jones oxidation. As expected, this reaction oxidizes primary alcohols to carboxylic acids and secondary alcohols to ketones.
Describe saponification
When long-chain carboxylic acids react with sodium or potassium hydride, a salt is formed. This process, called saponification, occurs by mixing fatty acids with lye (sodium or potassium hydroxide), resulting in the formation of a salt that we know as soap. Soaps can solvate nonpolar organic compounds in aqueous solutions because they contain both a nonpolar tail and a polar carboxylated head. When placed in aqueous solution, soap molecules arrange themselves into spherical structures called micelles. The polar heads face outward, where they can be solvated by water, and the nonpolar hydrocarbon chains are oriented toward the inside of the sphere, protected from the solvent. Nonpolar molecules, such as grease, dissolve in the hydrocarbon interior of the spherical micelle; the micelle as a whole then dissolves in water due to the polarity of its exterior surface. Note: subsequent acidification of the soap regenerates faty acids
How does Keq relate to Gibb's free energy?
When the equilibrium constant for a reaction is very large (much greater than 1) the reaction will be spontaneous and thus Gibb's free energy is negative
What is the difference in work between conservative and non-conservative forces?
When the work done by non-conservative forces is 0, or when there are no non-conservative forces acting on the system, the TME of the system (UE+KE) remains constant. The conservation of mechanical energy can be expressed as: ∆E=∆U+∆K=0 When non-conservative forces such as friction, air resistance or viscous drag are in play, TME is not conserved. The equation is: Wnonconservative= ∆E=∆U+∆K The Wnonconservative will be exactly equal to the amount of energy "lost" from the system (it just got transformed into some other energy {ex: thermal}) that is not accounted for in the TME equation.
When are solutes considered soluble?
When they have a molar solubility above 0.1 M in solution. When the change in Gibbs free energy is negative at a given temperature.
How do we write molecules in ionic equations?
When writing net ionic equations, all aqueous compounds should be split into their constituent ions. Solid salts, on the other hand, should be kept together as a single entity.
Describe isotopic notation
When written in isotopic notation, elements are preceded by their atomic number as a subscript and mass number as a super script.
How do range and standard deviation generally relate to one another mathemeatically?
Where the date are not available, the range can be approximated as four times the SD. However, this does not always hold true.
How do we estimate with division vs multiplication?
While in multiplication we adjust each number in an opposite direction (round one number down and the other number up), with division we are attempting to make proportional adjustments in the same direction (round both numbers up or down together)
What is a confidence interval? How do we create one?
With a confidence interval, we determine a range of values from the sample mean and standard deviation. We begin with a desired confidence level (95% is standard) and use a table to find its corresponding z- or t- score. When we multiply the z- or t- score by the standard deviation, and then add and subtract this number from the mean, we create a range of values.
How do we do addition and subtraction with significant figures?
With addition and subtraction, decimal points are maintained rather than maintaining significant figures. The convention for decimal points is the same as for significant figures: the answer may have only as many decimal digits as the initial number with the fewest decimal digits.
How are compound formulas written?
With the cation first and the anion second. Thus HCl implies H+ while NaH implies H-.
What is work and how is it calculated?
Work is the process by which energy is transferred from one system to another. It is calculated as: W= F*d = Fdcosθ
What is an equipotential line?
a line on which the potential at every point is the same. That is, the potential difference (voltage) on an equipotential line is zero. Furthermore, no work is done when moving a test charge q from one point on a line to another. Work is done, however, when moving a test charge q from one line to another, but the work depends only on the potential difference of the two lines and not on the pathway taken between them.
rarefaction means...
decompression
Draw Phenylalanine
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Draw a ketal
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Draw a logarithmic growth curve
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Draw a phase diagram
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Draw acetic acid
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Draw alanine
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Draw an acetal
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Draw an exponential growth curve.
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Draw glutamate
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Draw glycine
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Draw histidine
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Draw lysine
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Draw serine
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Draw the structure of benzoquinone
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Draw the structure of hydroquinone
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Draw threonine
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Draw tryptophan
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Draw tyrosine
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Practice number 7 on pg 363 of gen. chem book
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Write the Goldman equation and the Nernst equation
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review example #1 on page 214
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review example #2 on page 214
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Where is the focal point located?
halfway between the mirror and the center of curvature
How do we calculate magnification of a mirror or lens image?
m= - i/o *the sign of the magnification tells us the orientation of the image: a negative magnification signifies an inverted image, while a positive magnification signifies an upright image; if |m|>1 then the image is magnified , if |m| <1 then it is reduced. This is true for mirrors and lenses
How do you calculate slope?
m= y/x Slope is always rise over run because you have to get up from bed (rise) before you get moving (run)
Dichloromethane dissolves...
organic, uncharged substances (water prefers polar, charged substances because like dissolves like)
Are halogens oxidizing or reducing agents?
oxidizing *non-metals like to get reduced
What does frequency determine?
pitch; lower frequency sounds have lower pitch and higher frequency sounds have higher pitch
Where does urea come from?
protein breakdown: Ammonia (NH3) is a byproduct of the metabolism of nitrogen-containing compounds (like proteins), and as a base, can disturb the pH of cells and blood. The liver converts the ammonia to urea, a neutral compound, which travels to the kidney and is secreted into the nephron for excretion in the urine.
What is the formula for displacement in respect to acceleration?
x=v₀t+ ((at²) / 2)
What is the sum of the oxidation numbers in a neutral compound?
zero The sum of the oxidation numbers of the atoms present in a polyatomic ion is equal to the charge of the ion.
What is the formula relating the decay constant to the half life?
λ= 0.693/ T₁/₂
What's the formula for Gibbs free energy?
∆G= ∆H-T∆S Where T has to be in Kelvins (there is no negative Kelvin)
What is the formula for Gibb's free energy of an electrochemical cell?
∆G° = - nFE°cell *where n is the number of moles of electrons exchanged Note: since Faraday's constant is expressed in coulombs (J/V) , Gibb's free energy here is in Joules
What is the standard free energy formula given Keq?
∆G°rxn= -RTln Keq *where R is the ideal gas constant. Note: the greater the value of Keq, the more positive the value of its natural logarithm. The more positive the natural logarithm the more negative the standard free energy change. The more negative the standard free energy change, the more spontaneous the reaction.
What is the standard free energy formula ?
∆G°rxn= ∑G°f,products -∑G°f,reactants
What is the formula relating potential energy, work, and heat?
∆U= Q -W done by the system
What is the formula for thermal expansion for liquids?
∆V = βV∆T *note that when comparing between the expansion of liquids and solids β= 3α
What is the tan of 60 degrees ?
√3
What is a second order reaction?
A second-order reaction has a rate that is proportional to either the concentrations of two reactants or to the square of the concentration of a single reactant. For a reaction that is: aA +bB → cC + dD the rate law for a second-order reaction is: rate= k [A]^1[B]^1 or rate= k [A]^2 or rate= k [B]^2 *where k has the units M^-1s^-1
What are single-displacement reactions?
A single displacement reaction occurs when an atom or ion in a compound is replaced by an atom or ion of another element. For example, a solid copper metal will displace silver ions in a clear solution of silver nitrate to form a blue copper nitrate solution and solid silver metal. Note: single-displacement reactions are often further classified as REDOX reactions.
A water tower operator is interested in increasing the pressure of a column of water that is applied to a piston. She hopes that increasing the pressure will increase the force being applied to the piston. The only way to increase the pressure is to alter the speed of the water as it flows through the pipe to the piston. How should the speed of the water be changed to increase the pressure and force? Explain.
It should be decreased. This is a basic interpretation of Bernoulli's equation that states, at equal heights, speed and pressure of a fluid are inversely related (the Venturi effect). Decreasing the speed of the water will therefore increase its pressure. An increase in pressure over a given area will result in increased force being transmitted to the piston.
What does a second-order rate law tell us about a reaction?
It suggests a physical collision between two molecules, especially if the rate law is first-order with respect to each of the two reactants.
What is the formula comparing Keq and rate constants?
Keq= k (forward reaction)/ k-1 (backward reaction)
What are the empirical and molecular formulas of a carbohydrate that contains 40.9% carbon, 4.58% hydrogen, and 54.52% oxygen and has a molar mass of 264 g/mol. Use both methods
Method 1: 1. Determine the number of moles of each element in the compound by assuming 100-gram sample; this converts the percentage of each element directly into grams of that element. 2. Find the simplest whole number ratio of the elements by dividing the number of moles for each compound by the smallest number out of all obtained in the previous step. 3. The empirical formula is obtained by converting the numbers obtained into who numbers by multiplying them by an integer value. 4. To determine the molecular formula, divide the molar mass (264 g/mol given in the question stem) by the empirical formula weight. The resulting value gives the number of empirical formula units in the molecular formula. 5. Finally, find the molecular formula by multiplying by this ratio.
A large cylinder is filled with equal volumes of two immiscible fluids. A balloon is submerged in the first fluid; the gauge pressure in the balloon at the deepest point in the first fluid is 3atm. Next, the balloon is lowered all the way to the bottom of the second fluid, where the hydrostatic pressure in the balloon reads 8atm. What is the ratio of the gauge pressure accounted for by the first fluid to the gauge pressure accounted for by the second fluid?
The first step in answering this question is defining the different types of pressures. Atmospheric pressure is the pressure at the top of the first fluid exerted by air (at sea level, it is equal to 1atm). Gauge pressure is the pressure inside the balloon above and beyond atmospheric pressure; gauge pressure is the total (absolute or hydrostatic) pressure inside the balloon minus the atmospheric pressure. Gauge pressure depends on the density of the fluid, the constant of gravity, and the depth at which the object is submerged. Hydrostatic or absolute pressure is the total pressure in the balloon (that is, the gauge pressure and the atmospheric pressure together). Because we are given the gauge pressure at the bottom of the first fluid as 3atm, our task now is to calculate the gauge pressure accounted for by the second fluid. The hydrostatic pressure at the bottom of the cylinder is 8 atm. One of these atmospheres is atmospheric pressure pushing on the fluids. Another 3 atmospheres are accounted for by the first fluid that is pushing on the second fluid. Thus, the gauge pressure due to the second fluid is 8-1-3=4 atm. The ratio of the gauge pressures is therefore 3:4.
An anchor made of iron weighs 833N on the deck of a ship. If the anchor is now suspended in seawater by a massless chain, what is the tension in the chain? (Note: The density of iron is 7800 kg/m^3 and the density of seawater is 1025 kg/m^3). Explain your answer.
The tension is the difference between the anchor's weight and the buoyant force because the object is in translational equilibrium: T= Fg- Fbuoy. The object's weight is 833N, and the buoyant force can be found using Archimedes' principle. The magnitude of the buoyant force is equal to the weight of the seawater that the anchor displaces.
Describe the transition state theory
When molecules collide with energy equal to or greater than the activation energy, they form a transition state in which the old bonds are weakened and the new bonds begin to form. The transition state then dissociates into products, fully forming the new bonds. The transition state, also called the activated complex, has greater energy than both the reactants and the products. The energy required t reach the transition state is the activation energy. Once an activated complex is formed, it can either dissociate into the products or revert to reactants without any additional energy input.
Describe the effects the following conditions would have on the initial rate f reaction for a zero-order, first-order, and second order reaction: *Temperature lowered *All reactants' concentrations doubled *Catalyst added
Zero order: lowering the temperature would decrease the speed of the reaction, doubling the concentrations of the reactants would have no effect, and adding a catalyst would increase the speed of the reaction. First order: lowering the temperature would decrease the speed of the reaction, doubling the concentrations of the reactants would double the rate of the reaction, adding a catalyst would also increase the rate of the reaction Second order: lowering the temperature would decrease the rate of the reaction, doubling the concentrations of the reactants would quadruple the rate of the reaction, and adding a catalyst would increase the rate of the reaction
What is the formula for percent yield?
percent yield=(actual yield/theoretical yield) x 100
What is formula weight?
the sum of the atomic weights in the empirical formula of a substance; its units are amu per molecuel
What is molecular weight?
the sum of the atomic weights of all the atoms in a molecule; its units are atomic mass units (amu) per molecule
What is Archimedes' Principle?
the upward buoyant force on an object is equal to the weight of the fluid displaced by the object
