fl 1- chem/pys

question 27/ pourbaix diagram

-At an applied potential of -.44V and pH below 6, there is an equilibrium btw Fe (s) and Fe 2+ (aq) as shown by the line of demarcation. The fact that this line moves horizontally with increasing pH up until pH=6 means that this equilibrium is unaffected by changing pH. -the graph in general: maps out possible equilibrium phases of an aqueous electrochemical system. The predominant ion boundaries are represented by lines. The lines show equilibrium conditions, aka where the activities are equal (for the species on each side of that line). On either side of the line, one form of the species will instead be said to be predominant. -the diagrams do no take kinetic effects into account (meaning that the species shown as unstable might not react to any significant degree in practice) -HORIZONTAL BOUNDARY LINE= H+ and OH- IONS ARE NOT INVOLVED; INDEPENDENT OF PH. -SLOPED BOUNDARY LINE= BOTH H+ AND ELECTRONS ARE INVOLVED AND THE ELECTRODE POTENTIAL IS A FUNCTION OF pH -VERTICAL BOUNDARY LINE= NO ELECTRONS EXCHANGED, EQUILIBRIUM NOT AFFECTED BY ELECTRODE POTENTIAL; LINE IS AT A PARTICULAR pH.

Rods

-all of them have the same kind of photopigment.

disulfide bonds

-covalent bond derived from two thiol groups from cysteine. -think tertiary structure or quaternary also -can be intra (this would be for stabilizing the folding of a single polypeptide chain; ie tertiary structure) or intermolecular (multisubunit proteins suhc as antibodies; ie quaternary structure)

dehydration reaction

-dehydration of an alcohol is an E1 elimination reaction. There force, acid catalyzed dehydration of alcohols involves a carbocation intermediate, and rearrangement to form a more stable carbocation can occur.

Acid-Base Properties of Salts Video

(when a salt is dissolved in water, it breaks up into its ions, which move about independently in dilute solutions- under certain conditions these ions behave as acids or bases) Strong acid + Strong base: HCl + NaOH --------> H2O + NaCl (s) -So the above happens because HCl breaks up into H+ and Cl- and then the NaOH breaks up into Na+ and OH- (remember these both completely dissociate because they are strong!!). So then the H+ will combine with OH- to form water, and then the leftover Na+ and Cl will react to form NaCl salt. = example of an acid base neutralization rxn. Now lets think about an aq solution of NaCl by dissolving NaCl in water. NaCl (aq) will have some Na+ and Cl- and H2O. So lets think about what those would do in water. Ph of water is 7. Sodium ions don't react w water so they wont affect the pH of our solution. And now you may think that Cl- can act as a weak base an gain a proton from water, but that wont happen very well because the Cl-anion is the conjugate base to HCl. and we know that a very strong acid, like HCl is going to have a very weak conjugate base. So the Cl- anions can't take protons from water very well so the pH is unaffected. SO, the pH of our solution of NaCl is 7 still!! -In general: when you have a salt formed from a strong acid and strong base, they form neutral solutions. Weak acid + Strong base: CH3COOH + NaOH --------> H2O + CH3COO- Na+ All the NaOH will disassociate Na+ and OH- (remember its strong!). The OH- will take the acidic proton on CH3COOH. So once again, OH- and H+ will react to form water. And then lets think about the salt that forms here: So when you take an H+ away from CH3COOH, your left with CH3COO- ion. And we also still have Na+ ions. The Na+ can ionically bond with CH3COO- to form sodium acetate (salt). Now lets think about an aq solution of sodium acetate. CH3COO- Na+ (aq) In solution: you have Na+ cations which are not going to react w water so it won't affect the pH at all, BUT the acetate ions in solution will.... So we know CH3COO- is the conjugate base to acetic acid; so its gonna act like a bronsted lowry base and gain a proton (because acetic acid is a weak acid to begin with, its conjugate base is not the weak and is able to act as a base). Here, water will act as a bronsted lowry acid and donate a H+ to the acetate anion. This will form acetic acid. Since the H2O donates an H+, it becomes OH-. So what has happened in our solution here: The fact that the acetate anion is present, has increased the concentration of OH- in solution; so now the pH is no longer 7; we have increased the pH. CH3COO- (aq) + H2O ----------> CH3COOH + OH- <---------- -In general: When you have a salt that forms from a weak acid and a strong base, these salts form basic solutions with pH >7. (So like were kinda thinking of all these examples as two steps but theyre actually like all one!!) Strong acid and weak base: HCL + NH3 ---------> NH4+ Cl- So the HCL will all disassociate into H+ and Cl-. And so the H+ will protonate the NH3 (assume that weak things in general don't disassociate, the strong thing just does whatever its supposed to to them) to form NH4+. And then we have some Cl- anions that will ionically interact with ammonium to form ammonium chloride = salt. Now lets think about an aq solution of ammonium chloride. NH4+ Cl- In solution: You have Cl- anions won't affect the pH of water ( which is 7). But the NH4+ cations will react w water and affect the pH.... So the ammonium ion is the conjugate acid of a weak base. Because the base is weak, the conjugate acid is not that weak and can act as a bronsted lowry acid and donate a proton to water. So water will function as a bronsted lowry base an accept a proton. So if you take away an H+ from ammonium you get ammonia, and then if you add an H+ to water you get H3O+. So whats happening in our solution: Weve increased the concentration of H3O+ ions; this will lower the pH and make it acidic and so the pH <7. In general: A salt thats formed from a strong acid and a weak base form acidic solutions that decrease the pH. NH4+ + H2O --------> NH3 + H3O+ <---------

Ex: Calculate the pH of a .030 M HNO3 solution

-first of all you needa realize that HNO3 is a strong acid!! so it will ionize completely in water. -write out the formula HNO3 + H2O -------> H3O+ + NO3- -So HNO3 will donate its proton to water and water will turn into hydronium; and then HNO3 losing a proton will turn into NO3-. -since HNO3 is strong, we get 100% ionization and EVERYTHING turns into our products!! -So when the question says that there is .030 M of HNO3, there is now .030 M of H3O+ because all the HNO3 turned into H3O+ bc its a strong acid! SO, pH= -log[H3O+] pH= -log [.030] pH= 1.52 a shortened version of the formula above: HNO3 -------> H+ + NO3- pH= -log [H+]

focal length

-focal length: distance from the lens to the focal point -for converging/convex lenses, the focal length is always positive, while diverging/concave lenses always have a negative focal length.

phosphorylation of amino acids

-happens on OH groups!!(but not all the time, but this is why ser, thr and try are the most commonly phosphorylated) - on serine, threonine and tyrosine side chains (often called 'residues') through phosphoester bond formation, -on histidine, lysine and arginine through phosphoramidate bonds -aspartic acid and glutamic acid through mixed anhydride linkages. basically it can occur on all the charged residues and then just memorize thats it also on serine, threonine and tyrosine. most commonly thought, tyrosine, serine and threonine are phosphorylated by protein kinases.

How is a buffer prepared?

1. mixing a large volume of a weak acid w its conjugate base (for example acetic acid and acetate ion (CH3COOH and CH3COO-) 2. mixing a large volume of weak base w its conjugate acid (ammonia and its ammonium ion (NH3 and NH4+) note** think of these weak acid base def as bronsted ones! phosphate buffer is commonly used= weak base + conjugate acid = HPO4^2- and H2PO4-

thin lens formula

1/F= 1/O + 1/i -units need to be in meters!! O= distance between the object and the lens of your eye; always positive (if your dealing with a single lens) i= (image); image is a certain m away on the other side of your lens (aka your retina; which is where the image forms). Image distance will be positive if it is on the opposite of the lens than the object (same side as eye!) -for question 11; both O and I are positive because in a lens system, the image should be on the opposite side of the lens! This is the case here. You can remember this by knowing that this is usually how a lens works. -**note that the focal length is F. so if it asks for focal length, you would needa inverse it!

conversions

100 cm = 1 meter 1 meter= 100cm 1 km= 1000 meter 1 m= .001 km

tip

2 cm = .02 m

Cones

3 types of cones; each type has a different photopigment; this is what makes the cones sensitive to diff wavelengths so it can detect different colors

standard atmospheric pressure

760 mmHg

Conversion

9 L its 9000 ml Think about it!!! A liter is way bigger than a ml so the ml number would be higher!

opsin

A membrane protein bound to a light-absorbing pigment molecule. -the protein that makes up a photopigment basically. -variety of opsins= can detect color

tip

A stereospecific reaction only produces one confirmation

hydronium ion

H3O+

question 10-Acetic acid and ethanol react to form an ester product as shown below. In determining which reactant loses the -OH group, which of the following isotopic substituions would be most useful?

If you wanna determine which OH group ends up leaving, you need to label the O on either the ethanol or the O on the R group of acetic acid because these are the only two -OH groups present. Switching the H's for D's wouldnt do anything because both H's end up forming water and would give you no indication of -OH movement.

finding percentages the formal way

If you want to know what percent A is of B, divide A by B. (B going into A). Then take that number and move it two decimal places to the right.

question #45

In the above figure, 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? Work: -since it says height, you know you need to use the Magnification formula. -you have do but you need di!! 1/F = 1/o + 1/i 1/F = 1/3F + 1/i 1/F -1/3F = 1/i 3/3F -1/3F = 1/i 1/i = 2/3F Solve for i. i = 3F / 2 Now we know from the magnification formula that M = -di/do = hi/ho so.... (note that the magnification formula wants di and do, not the inverse!!!!) (3F/2) / 3F = hi/ho 1F/2F = hi/ho 1/2 = hi/ho Final answer= 1/2 ***should review this on paper bc the algebra can get confusing!!

fact

Increasing H+ concentration= lowering Ph= more acidic

Ka

Ka < 1 is a weak acid Ka> 1 is a strong acid

question 22 - look at it!

Compared to micellular Compound 1, Compound 2 is structurally more rigid as a result of what type of interaction? A.Intermolecular hydrogen bonding B.Intermolecular covalent bonding C.Intramolecular hydrogen bonding D.Intramolecular covalent bonding -relevant passage info "Molecules of Compound 1 spontaneously self-assemble into cylindrical micelles in water at pH 4 but freely redissolve at pH 8 (Equation 1). Oxidation of self-assembled, micellular Compound 1 with iodine resulted in a solid material (Compound 2) that was stable to alkaline solutions (Equation 2).Reaction of Compound 2 with dithiol (Compound 3) resulted in reformation of Compound 1 (Equation 3)." reddit: the passage states that compound 1 undergoes an oxidation reaction. A majority of the time, oxidation reactions (redox) involves formation of covalent bonds due to removal of electrons. Think oxidation of cysteine to make disulfide bonds. these bonds are covalent! -You know that compound 1 gets oxidized to become compound 2- which is rigid. Compound one has cysteine residues, which you can tell by looking at the structure.....so cysteine residues get oxidized to form rigid structures btw molecules. While the compound does have H bonding, the existence of these bonds would not explain why the oxidation of Compound 1 resulted in a more rigid structure, as oxidation does not necessarily increase the strength of h bonding. -another way to look at it: If you look at the 3rd reaction, a dithiol is able to reduce Compound 2 back into Compound 1. Thiols are reducing agents (e.g. Glutathione) and they're able to break disulfide bonds. The fact that a reducing agent caused Compound 2 to go back to compound 1 means that disulfide bonds were necessary to go from Compound 1 to compound 2. Disulfide bonds are an example of intermolecular covalent bonding -since the passage says "oxidation of self-assembled, micellular Compound 1 with iodine resulted in a solid material" this means that in the presence of iodine the oxidation is occurring at compound two is forming. So, iodine is an oxidizing agent, and would form the cysteine intermolecular disulfide bonds. so multiple molecules are oxidized together to form compound 2. (the passage says the compound 1 is a micelle, which is made up of multiple molecules already. just fyi) ANSWER IS B

Calculate the pH of an aqueous solution that contains .11 H of Ca(OH)2 in a total volume of 250 ml.

Ca(OH)2 ------> Ca 2+ + 2OH -Balancing this means you have 2 mol of OH for every 1 mol of Ca(OH)2 Step 1: Find total moles of OH- have .11 GRAMS of Ca(OH)2 to get the moles you needa divide by the molar mass of Ca(OH)2 .11 g / 74 g/mol = .0015 mol you need to multiple .0015 by 2 because you need TOTAL MOLES OF OH. so it equals .003. Step 2: Find concentration of OH- Then you need to find concentration which is M, which is moles/liter -they give you 250 ml = .25 liters .003 mol/.25 liters = .012 M [OH-] pOH= -log(.012) pOH= 1.92 14-pOH= pH 14-1.92= 12.08 pH=12.08

question 35

This question is rlly tricky!!! TIP: if you know you did the question right and the answer is not there, go back and re read the question because chances are that you misread something or didn't realize a detail asked in the question. -Compared to the wild-type LipA, what is the change in net charge in variant XI at pH 7? A.+4 B.+3 C.−3 D.−4 Asking for the CHANGE in net charge!!!!!; not the net charge! The net charge when from +2 to -2.... so the change in net charge is -4.

Ohm's Law

V= IR V= voltage in V I= current in A R= resistance in Ω (ohms)

ex: Calculate the pH of a 1 M solution of CH3COOH (aq)

WEAK ACID= ICE BOX. CH3COOH + H2O ------> H3O+ + CH3COO- with a weak acid, not all the acid ionizes !! So lets say 1 mol of CH3COOH ionizes, then that will form 1 H3O+ ion and 1 CH3COO- ion. I 1.00 0 0 C -x +x +x E 1.00-x x x equilibrium expression: (always products over reactants!!) Ka = [H3O+] [CH3COO-]/ [CH3COOH] Plug in what you know! (would need to be given kA) 1.8 x 10^-5 = (x)(x)/(1-x) assume x<<<<<<<1 if you assume that, then 1-x will be approx 1 1.8 x 10^-5 = x^2 / 1 just take square root of 1.8 x 10^-5 x= .0042 Now remember what x represents; x represents the [H3o+] at eqilibrium. and now we can calc pH!! pH= -log[.0042] pH= 2.38

fact

adding a strong acid to a solution of weak acid will decrease the amount of ionization of the weak acid (related to common ion effect i think)

functional group that is formed when aspartic acid reactions w another amino acid to form a peptide bond

amide group (the functional group that forms during peptide bond formation)

micelles

an aggregate of molecules in a colloidal solution, such as those formed by detergents. -formed by self assembly of amphiphilic (same thing as amphipathic) molecules. -formed in aqeuous solution whereby the polar region faces outside and the nonpolar regions form the core. -like a liposome but its doesnt have like an empty space inside! -Micelles are lipid molecules that arrange themselves in a spherical form in aqueous solution

What type of functional group is formed when aspartic acid reacts with another amino acid to form a peptide bond?

an amide group

Buffer

an aqueous solution that resists changes in Ph upon the addition of small volumes of strong acids or bases. -adding a water to a buffer (or allowing water to evaporate from the buffer) doesn't change the ph of a buffer significantly -buffer = 1. pair of weak acid and its conjugate base 2. pair of weak base and conjugate acid

Kinase

an enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule. -specifically uses ATP!!!

fact

artery walls are more elastic than capillary walls.

fact

at physiological pH: -the NH3 group is protonated so it has a + charge -the COO- group is not protonated, so it has a - charge. OVERALL NET CHARGE= 0 lower pH/acidic -the NH3 group stays protonated so it has a + charge -the COOH group is now protonated, so it has a 0 charge. OVERALL NET CHARGE= +1 higher pH/basic -the NH2 group is deprotonated so it has a 0 charge -the COO- group is not protonated, so it has a - charge. OVERALL NET CHARGE= -1

STP (standard temperature and pressure)

conditions of 0.00°C and 1 atm pressure

Peptide bonds are

covalent

index of refraction formula

definition: a measure of the amount a ray of light bends when it passes from one medium to another speed of light in a vacuum will be given! = 3.0 x 10^8 m/s -they will have to give you the speed of light in the medium -plug and chug

rf value

distance travelled by compound/ distance travelled by solvent -some compounds in a mixture travel almost as far as the solvent does; some stay much closer to the base line. The distance traveled relative to the solvent is a constant for a particular compound as long as you keep everything else constant- the type of paper and the exact composition of the solvent fr ex. -if they give you a question on this, you literally just divide values you see on the diagram. (look at number 3)

question 13

dont get this confused with buffers bc its not buffers!!!!! -Which of the following will decrease the percentage ionization of 1.0 M acetic acid, CH3CO2H(aq)? A.Chlorinating the CH3 group B.Diluting the solution C.Adding concentrated HCl (aq) D.Adding a drop of basic indicator -CH3COOH is a weak acid! -HCL is a strong acid and it will 100 ionize. This will increase the amount of H+ or (H3O+) in the solution, thus decreasing the percentage that CH3COOH ionizes. CH3COOH + H2O ---------> H3O+ + CH3COO- HCL + H2O --------> H3O+ + Cl- reddit: -Adding HCL, will cause more H+ (H3O+); this will shift the equilibrium to the left. Shifting the equilibrium left = less product forming aka CH3COOH will ionize less!! (also, when you shift left your making more reactants so your making CH3COOH rather than ionizing it) -common ion effect! A: chlorinating the CH3 group: Cl- is very electronegative so it will hog electron density, so it will be good at distributing the negative charge produced when protonation happens. This means that the conjugate base will be more stable and preferred. so we can infer that it increases ionization. -It will add an inductive effect by withdrawing the electrons, increasing the acidity of the proton. This leads to more ionization.

Lewis acid

electron pair acceptor -a and a;

Lewis base

electron pair donor b and then flip the b=d

Intensity of electromagnetic radiation

energy emitted per unit time

Facts

energy of electromagnetic radiation = directly proportional to the number of photons emitted intensity of electromagnetic radiation = energy emitted per unit time SO Intensity is directly proportional to the photons emitted

Half life question

ex: "What fraction of an O15 sample decays in 10 min" It will tell you what the half life of O15 is. Lets say it says that its 2 min. 10/2 = 5 half lives. (1/2)5 = 1/32 will be left after 10 min... so 31/32 decays (i did this and go it right but i did it the long way)

weak base equilibrium Khan academy video

ex: same thing as acid but w a weak base!!! you have to do an ICE BOX and everything is the same. except in the end, you'll get [OH-] concentration, so you would need to to the thing with the pOH+ pH =14 formula in order to find the pH.

ex:

lets say you have a buffer of acetic acid and acetate ions (CH3COOH) and (CH3COO-) (weak acid and conjugate base) -when a strong acid is added, the acetate ions neutralize the H3O+ ions; producing more acetic acid (which is already a component of the buffer obv) CH3COO- + H3O+ ---------> CH3COOH + H2O -on the other hand, when a strong base is added, the acetic acid consumes the OH- ions, produce more acetate ions (which is already a component of the buffer). CH3COOH + OH- ----------> CH3COO- + H2O ^^this process is the same even if your buffer is weak base + conjugate acid!! the process is the same

another ex:

lets say you have a buffer of ammonia (weak base) and ammonium ions (conjugate acid) (NH3 and NH4+) -When a strong acid is added, the ammonia neutralizes the H3O+ (hydronium) ions, producing ammonium ions (which is already a component of the buffer) NH3 + H3O+ -------> NH4+ + H2O *note that NH4+ is already present in buffer -When a strong base is added, the ammonium ions consume the OH- (hydroxide) ions, producing ammonia (which is already a component of the buffer). NH4+ + OH- -------> NH3 + H2O *note that NH3 is already present in buffer **the fact that the NH3, NH4+ and etc are already present in the buffer, means that we remove the hyroxide or hydronium ions, preventing the solution from becoming basic or acidic respectively.

magnification

m=-di/do = hi/ho focal length formula only tells you the horizontal length of things; not about how tall the image or object is; nothing about the height. thats why you need to use this formula + M = image is right side up (I is negative) -M= image is upside down/inverted (I is positive) For all the below you need to take the absolute values !! M>1 = image is magnified M=1 = image is the same size as object M<1 = image is diminished for all these calculations just use the first part of the formula m=-di/do -note that the magnification formula wants di and do, not the inverse!!!

Electrophile

molecule or ion that accepts a pair of electrons to make a new covalent bond -same thing as a lewis acid -any molecule, ion or atom that is electron deficient in some way can behave as an electrophile. Electron deficiency would include a formal positive charge, a partial positive charge (polar bond) or an open octect.

Nucleophile

molecule or ion that donates a pair of electrons to form a new covalent bond -same thing as a lewis base -any molecule, ion or atom that has electrons that can be shared can be a nucleophile -most common indications are formal negative charge, partial negative charge (polar bond), lone pairs.. -nucleophilic ATTACK. (arrow is usually form nucleophile to electrophile)

pH

pH= -log[H3O+] 14= pH + pOH

Weak acid equilibrium Khan academy vid

pKa= -log Ka pKa and Ka are inversely proportional .... Strong acid= high Ka, low Pka

pOH

pOH= -log [OH-]

P=QR; Q=VA cardiovascular physiology

pressure =flow x resistance resistance increases, then flow decreases pressure increases, flow increases resistance increases, pressure increases FLOW IS NOT THE SAME AS VELOCITY !! Flow is the volume of blood, velocity is how fast the blood is traveling. Q=VA flow= velocity x area -higher area, slower velocity -higher area, more flow -higher velocity, more flow

Bronsted-Lowry base

proton acceptor 1 proton difference!!

Bronsted-Lowry acid

proton donor 1 proton difference!!

fact

stronger the acid, the weaker the conjugate base

fact

stronger the base, higher Kb stronger the acid, high Ka

dividing exponents

subtract the exponents (1 x 10^ -34)/(1 x 10 ^18) = (1 x 10 ^-52)

paper chromatography

the stationary phase is a very uniform absorbent paper (usually cellulose) the mobile phase is a suitable liquid solvent or mixture of solvents. -Polar components will be attracted to the water molecules attached to the cellulose (paper) and not attracted to a nonpolar solvent. The chromatogram will not contain the polar components, given that it doesn't climb up the paper with the nonpolar solvent. Nonpolar components will climb up the paper with the nonpolar solvent. These components spend more time in the stationary phase rather than the mobile phase therefore the rate of moving up the paper is slow. If it were the opposite and nonpolar components were in a polar solvent, then the same thing will occur. The mobile phase can be various organic solvents or mixture. Th

Question 6

the substitution of pronated alcohols is subject to steric hinderance. this inhibits the ability of nucleophiles to collide with the reacting electrophile center and slows the rate of reaction.

"residues that can be cross-linked for additional structural integrity"

think cysteine residues and disulfide bonds

Phosphorylase

transfers a phosphate group to a molecule from inorganic phosphate -doesn't use ATP for its phosphate, it uses a phosphate group from inorganic phosphate (HPO4). an inorganic phosphate is a phosphate + hydrogen.

chromatography

used to separate mixtures of substances into their components. All forms of chromatography work on the same principle. -they all have a stationary phase (a solid, or liquid supported on a solid). -the mobile phase flows through the stationary phase and carries the components of the mixture with it. Different components travel at different rates. There are reasons for this..

VESPR theory

valence shell electron pair repulsion theory, because electron pairs repel, molecules adjust their shapes so that valence electrons pairs are as far apart as possible

standard state conditions

T = 25° C (or 298K), P = 1 atm -in thermodynamics: used for measuring enthalpy, entropy Gibb's free E, and voltage.

Conversion

Tera means 10^12 thz -----> hz multiply by 1 x 10^12 hz -----> thz multiply by 1 x 10^-12

Capillaries

-high resistance -low pressure -low flow -small area -low velocity -people get confused by this in relation to the P=QR and Q=VA formula because they say okay based on the formula, if there is high resistance than Pressure should be high too. And if the area is small, why is the velocity low. But when we talk about a single capillary, there is high resistance and small area, but the pressure is low and the velocity is low. BUTTT what you dont realize is that the above for a single capillary is true; but you need to think of capillaries as like a capillary bed being a group of circuits in parallel. The resistance isn't summed directly but rather added in reciprocal because there are so many avenues through which current can pass; adding them reciprocally makes the total resistance lower. (relative to one another and your basically taking the totality of them!); resulting in a total lower resistance for the capillary bed. So this lower total resistance makes sense that the pressure is low. Because of this also, the total cross sectional area is LARGER, and velocity is slower.!!

strength

-inverse of focal length (basically S= 1/F) S= 1/O + 1/i (this was given on the test tho!!) -units need to be in meters!!

pneumonic for base definitions!

-memorize bronsted def; then just know that for lewis, the opposites are donor vs acceptor and its talking about electron pairs instead of protons!! bronsted acid is a proton donor and bronsted base is a proton acceptor; SO lewis acid is an electron pair acceptor and a lewis base is an electron pair donor.

silica gel

-often used a stationary phase for chromatography -it is polar; so nonpolar components tend to elute before polar ones, which bind to the silica. (like binds like)

Ex: Calculate the pH of a .030 M NaOH solution

-same thing as above except this is a strong base, not a strong acid!! -NaOH is a strong base so it will completely ionize in water!! NaOH + H2O -------> Na+ + OH- So if we have .2 M of NaOH, then we will also get .2 M of OH- in solution. pOH= -log[.2] pOH= .7 14= pOH + pH 14- .7= pH pH= 13.30

Enzymes

-stabilize the transition state which changes the activation energy of the reaction (by lowering it)

Strong acids and strong bases Khan academy video

-strong acids and bases ionize 100% in water

Buffer and pH

-the function of a buffer is to keep the pH of a solution within a narrow range -the ration of weak acid/conjugate base directly influences the pH of a solution. in other words, the actual concentrations of them influence the effectiveness of a buffer. -the more weak acid/conjugate base molecules available, the less of an effect the addition of a strong acid or base will have on the pH of a solution. HA = weak acid A- = conjugate base

valence bond theory

-the idea that covalent bonds are formed when orbitals of different atoms overlap -explains hybrid orbital linear= sp= 1s, 2p = 2 sp hybrid orbitals and 2P left over trigonal planar = sp2 = 1s, 2p = 3 sp2 hybrid orbitals and one P left over tetrahedral= sp3 square planar= dsp2 trigonal bipryamidal= dsp3 octahedral= d2sp3 pentagonal bipyramidal= d3sp3

Ionization

-the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons

question 4- which of the following statements does not correctly describe the dehydration of malic acid to fumaric acid and maleic acid

-the reaction occurs most readily with tertiary alcohols -the reaction involves the loss of a water molecule -the reaction has a carbocation intermediate -the reaction is stereospecific -D is false because the fact that both fumaric and maleic acid are produced means that the dehydration of malic acid is NOT stereospecific. -A stereospecific reaction only produces one confirmation -the key here is to know that the reaction occurs through a carbocation intermediate. upon losing that fourth bond and forming a carbocation, you will lose all stereochemistry, so the reaction couldnt be stereospecific even if it wanted to.

How does a buffer work?

-when a strong base is added, the acid present in the buffer neutralizes the hydroxide ions (OH- ions) -when a strong acid is added, the base present in the buffer neutralizes the hydronium ions (H3O+). -think of it like adding strong acid is adding H3O+ and adding strong base is adding OH- ions

Why is the velocity of blood flow slower in capillaries than in arteries?

A.Capillary walls are more elastic than arterial walls. B.Capillaries have less resistance to blood flow than arteries. C.The total cross-sectional area of capillaries exceeds that of arteries. D.Blood pressure is higher in the capillaries than in arteries. -D is just wrong because arteries are closer to the heart, so the blood gets freshly pumped from the heart into the arteries. so pressure in the arteries is much higher and then decreases after that. -A wrong: Artery walls are more elastic than capillary walls -B wrong: capillaries have more resistance to blood flow because they are smaller in diameter. -the higher number of capillaries in the body means that the total-cross sectional area of these vessels is larger than any other vessel type. reddit: (hypothetically, fluid flow in a single capillary would be faster than flow in a single artery bc smaller area = faster velocity but dont think of it like this!) basically, dont think of it like your comparing one single capillary to one single artery. often times, when they ask about vascular velocity are often asking you in the context of total cross-sectional flow. -another way to think of it: our blood is transferring things; oxygen, co2, nutrients, waste. It needs to be slower on the capillary side to be able to make those transfers and then faster in the big vessels because it's not doing anything useful there. So slower blood flow in the capillaries ensures increased nutrient and gas exchange within tissue. VELOCITY IN A LARGE AREA= SLOW. FACT. So, think about the area of a single capillary compared to like, an artery. Pretty small, right?. Now multiply that by how many capillaries are in the body. Combined, now you've got a very very large area. What happens to velocity in a very very large area?- slow velocity HYPOTHETICALLY IN A SINGLE CAPILLARY... the hypothetical fluid flow in a single capillary with a certain diameter would hypothetically be faster than the flow in an artery with a larger diameter, by Q = VA. Smaller area, faster velocity to maintain flow rate.But questions asking about vascular velocity are often asking you in the context of total cross-sectional flow

cyanide

CN- -didn't look at passage in depth enough.

Energy of a photon equation

E=hf E= energy of the photon in Joules H= planck's constant- given (J/s) f= frequency of the light in hertz OR E= hc/λ c= speed of light -given (m/s) λ= wavelength of a photon -Hertz just depends on the info you have!!!

ex:

Lets say we add a strong acid such as HCL to a buffer. Initially, the protons produced will be taken up by the conjugate base (A-). A- + HCL -----> HA + Cl- -This will slightly change the pH by altering the ratio of [HA]/[A-] and [A-] and [HA] are constantly changing, but as long as there is enough A- (weak base) present, the change in pH will be small. -BUT, if we keep adding HCL, eventually A- will run out. Once there is no more A- left, any additional HCL will donate its proton to water! (HCL + H2O -----> H3O+ + Cl- btw this is an example of ionization!!!!! here we have 100% ionization bc HCL is a strong acid). This will dramatically increase the concentration of [H3O+], leading to a drastic change in pH of the solution. SO, In order for a buffer to be effective... -the number of moles of the weak acid and its conjugate base must be significantly large compared to the number of moles of strong acid or strong base that may be added -the best buffering will occur when the ration of [HA] to [A-] is almost 1:1. In that case, pH= pKa.

hydroxide ion

OH-

Ex: Calculate the pH of a .25M solution of CH3COONa (aq). (calculating pH of salt solutions)

So in solution, we will have Na+ cations and CH3COO- anions. The Na + cations wont react w water but the acetate anions will. So since CH3COO- is a conjugate base.... CH3COO- + H2O --------> CH3COOH + OH- I .25 0 0 C -x +x +x E .25-x x x Kb= [CH3COOH] [OH]/ [ CH3COO-] assume x<<<<<<<1 Kb= x2/25......DIDNT FINISH

question 23

Which amino acid residues were incorporated into Compound 1 to promote the adhesion of cells on the scaffold surfaces? A.Arg and Gly B.Cys and Gly C.Cys and Asp D.Asp and Arg reddit: -using process of elimination. Glycine doesn't really do much. Its nonpolar, alipathic, and not chiral. so you can eliminate A and B. -Cysteine is involved in cross-linkages, not what the question is asking. so you can also eliminate d. -Asp and Arg are both charged, which would help to adhere to surfaces that most likely also have a charge. -you could also have looked at the diagram!! They are referring to region 5. Since region 4 is where the phosphorylation happens, the area to the right where you see the phosphate is region 5. You can see that there is both Arg and Asp right there!! Need to be able to recognize AA on structures quickly so this is a good practice question!!.

autoionization of water vid khan academy

[H3O+] = [OH-] neutral [H3O+] > [OH-] acidic [H3O+] < [OH-] basic

If they give you [OH-] concentration and ask for pH...

[H3O+][OH-]= 1 x 10^14 plug in and divide using this formula!!!^^ OR Can just find the pOH and subtract from 14.

multiplying exponents

add the exponents (1 x 10^ -34) (1 x 10 ^18) = (1 x 10 ^-16)

common ion effect and buffers (seen this question alot!)

a decrease in the solubility of an ionic compound caused by the addition of a common ion Okay so you have acetic acid in solution and we know whats gonna happen: CH3COOH + H2O ------> H3O+ + CH3COO- <------ So now theres a concentration of CH3COO- anions in solution. What happens if you added some sodium acetate? CH3COO-Na+ -So when you add this to your solution, you now have some more acetate anions; you have increased the concentration of one of your products. And Le chateliers principle says that when you increase the [product], your equilibrium will shift left; And that means that some of this acetate anion will react w some hydronium ion when your eq shifts left. This decreases [H3O+], and when you decrease [H3O+], the pH of the resulting solution increases. SO, your acetate ion is your common ion and this is the common ion affect. So there are two sources for your acetate anion: one is through the ionization of acetic acid and the other is the sodium acetate that you added in. And so we expect a pH thats higher than just the acetic acid alone.

Lipase

a pancreatic enzyme that catalyzes the breakdown of fats to fatty acids and glycerol or other alcohols. -digests fats -hydrolyzes fatty acids -so AAMC says that it hydrolyzes fatty acids, but google says that it breaks down neutral fats (triglycerides) into glycerol (an alcohol) and free fatty acids.

question 36

got this right but look at the graph bc you didnt understand exactly what it was. -you have to look at this graph like the line is connecting a bunch of points. for each point, you took that specific variant or WT, and you heated it to a certain temperature, then you let it cool and saw its activity. this is how you need to interpret the graph! -You know that process is reversible because: the ones you denatured in 1A, are back in figure 1B; you just need the right pH. So even though their activity lowered on the first graph, the activity of the proteins after cooling down again is almost 100% (at PH4) so you know that they did not stay denatured!! -Also, denaturing is the breakdown of an level pf protein except the primary structure. Because the primary structure is still together, there is no reason why it wouldnt be able to fold again (i dont know if you can assume this on the test!!!) -answer D is wrong because when you heat it to 55, the activity retention is at around 20 on the graph---this is what i mean by looking at it as a POINT! You should not think of the line as a decrease in activity. need to pay attention to thing. you can clearly see that the graph has points!

In the chromatography of the reaction mixture, water absorbed on cellulose functioned on the stationary phase. What was the principal factor determining the migration of individual components in the sample.

hydrogen bonding. -relative amount of hydrogen bonding to the stationary phase (water) will determine the relative rate of migration of various components in the sample. z

ideal gas

ideal gas law: PV= nRT a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory which states : -gas particles are in constant/random motion and exhibit perfectly elastic conditions when colliding (meaning there is no loss of energy during the collisions) -average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only -intermolecular forces are negligible/ ideal gas obeys to no intermolecular forces -ideal gas molecules have negligible volume (although all the gas molecules together can occupy a large volume) -pressure is due to collisions btw molecules and walls of the container -STP: Temperature = 0 degrees C (or 273 K) Pressure= 1 atm -1 mol of an ideal gas occupies 22.4L

exponent fact!!!!!! just memorize bc idk how this works.

lets say you have (40.26 x 10^ -20) it becomes: (4.0 x 10^ -19) So moving the decimal over to make it smaller, it subtracts one from the negative. BUT lets say you have (40.26 x 10^ 20) it becomes: (4.0 x 10^ 21)