Gen chem 1-10 practice exam questions
Zero order kinetics the y -axis units are
concentraion, slope is -k
To separate a homogeneous mixture of salt water, which of the following pieces of laboratory equipment is necessary?
condenser
Oxoacids are acids that
contain oxygen
Which of the following changes will result in the greatest increase in solubility of O2 gas in water?
Increase pressure of the gas and decrease temperature of the solution
only temperature can change the
Ka.
The solubility of solid AgCl in water was found to be 1.34 x 10-5 mol/L and the solubility of solid AgBr in water was 7.07 x 10-7 mol/L. Which of the following conclusions can be made?
Ksp is solubility The higher the molar solubility is, the larger the Ksp value will be. AgCl, with a molar solubility of 1.34 x 10-5 has a higher Ksp than AgBr.
What is the concentration of Pb2+ at equilibrium if the Ksp of PbCl2 equals 1.8 x 10-5 in an aqueous solution of pure water?
Ksp= (Pb 2+)(cl-)^2
Species that can accept an electron pair are
Lewis acids
species that can donate an electron pair are
Lewis bases.
Which of the following descriptions accurately describes a metal?
Metals tend to form cations in aqueous solution.
Strong bases include
Mg(OH)2 Ca(OH)2 Sr(OH)2 Ba(OH)2
why along the same period, a non-metal has a smaller atomic radius than a metal?
Non-metals have a higher effective nuclear charge
The formula for osmotic pressure is:
Pressure= iMRT i is the # of ions M is molarity R is 0.082 T is temp in K
Kc is larger when the reaction shifts to the
RIGHT
What are the molecular shape and the hybridization of the central atom in phosphorus pentachloride?
Trigonal bipyramidal, sp3d
A fixed sample of an ideal gas occupies a volume of 1.2 L at 30°C and 1.0 atm. What volume will the gas occupy if the temperature is increased to 60°C at constant pressure?
Use V1/t1=v2/t2 Convert temp into K
If KCl is added to distilled water, which of the following properties would decrease in value?
Vapor pressure of the solution
the dense particles within an atomic nucleus.
a nucleon
A state function
a property whose value does not depend on how that state was achieved. Enthalpy, volume, mass and Gibbs free energy are all state functions.
positron emission
a proton converts into a neutron and emits a positron
isoelectronic series
a series of atoms, ions, or molecules having the same number of electrons
In a disproportionation reaction
a substance is simultaneously oxidized and reduced, giving two different products.
ideal gases
a theoretical gas that conforms to kinetic molecular theory and behaves as described by the ideal gas law, PV = nRT
Filtration
an effective technique to separate a solid from a liquid.
What is an activated complex?
an unstable arrangement of atoms that forms momentarily at the peak of the activation-energy barrier
Oxidation occurs at the Reduction occurs at the
anode cathode
reaction intermediates never
appear in rate equations.
The standard cell potential of a voltaic cell is:
ecell= E reduction (2)-E reduction (1)
A non-spontaneous electrochemical cell is an
electrolytic cell
all transition metals are more
electronegative than alkali metals
the forward reaction never has the same
entropy as the reverse reaction
With increasing temperatures, which of the following occurs?
entropy increases
At increasing temperatures, an exothermic reaction at equilibrium will proceed at a
faster rate while its Kc decreases
The energy of a photon is directly proportional to which of the following?
frequency
Which type of nuclear decay will NOT change the atomic number of the element?
gamma decay
Deposition
gas to solid
A graduated cylinder or pipet are common
glassware for accurately measuring volumes of liquid.
weak acid/strong base has a pH of
greater than 7
Weak acid and strong base will have a pH
greater than 7 at the equivalence point.
sublimation will involve the
greatest increase in enthalpy and entropy.
Enthalpy (ΔH) refers to
heat energy.
If electron affinity is low, and ionization energy is low, atomic radii would be
high for both atoms.
Network covalent bonds have
high melting poing hard, and are non conductive
ionic bonds have
high melting point are brittle and hard
A real gas is most likely to exhibit ideal gas behavior under which of the following conditions?
high temperature and low pressure
Gamma rays have the
highest energy and shortest wavelengths
while decreasing/increasing temperature only results in
horizontal movement of the substance.
The group 1 elements, alkali metals, react vigorously with water to produce
hydrogen gas.
The concentration of products will not affect the rate of an
irreversible reaction.
The compound losing electrons (ie, becoming more positive)
is getting oxidized.
The compound gaining electrons (ie, becoming more negative)
is getting reduced.
Electron affinity
it increases as you go up in a group (column) and right in a period (row).
The titrant is a
known solution that is added in order to find the titrant's concentration
Water molecules in an aqueous solution will have the strongest interactions with ions with which of the following characteristics?
large charge and small size
Kc is smaller when the reaction shifts the
left
weak base and strong acid has a pH of
less than 7
Weak base and strong acid will have a pH
less than 7 at the equivalence point
in an exothermic reaction, the forward activation energy is
less than the reverse activation energy.
Evaporation is the transition at the surface of a
liquid from liquid to gas
In equilibrium expressions no
liquids or solids included in the equilibrium constant expression.
first order reaction y-axis units are
ln concenetration, slope is -k
conjugate base
lost proton
molecular bonds have
low melting points and are non conductive
If a liquid is found to have weak intermolecular forces, then that liquid will generally have a
low viscosity
The forward reaction has a
lower activation energy.
higher vapor pressure means
lower boiling point and weaker intermolecular forces
Radio waves have the
lowest energy and longest wavelengths.
Paramagnetic means attracted to
magnetic fields. They have at least one unpaired electron in their orbitals.
For multiplying and dividing, the number of significant figures is determined by the
measurement with the fewest number of significant figures.
barometer
measures air pressure
electronic balance
measures mass
thermometer
measures temperature
Decreasing the pressure decreases the boiling point and increases the
melting point
Adding more solute will increases
molarity,ostomitic pressure, molality and boiling pressure.
Compounds are
molecules composed of two or more bonded different elements that exist in fixed proportions.
the more sponatous reaction is the one that is the
most positive and the strongest reducing agent along with being oxidized
A reaction is spontaneous if ΔG is
negative
As something becomes more organized (from a gas → liquid → solid), ΔH and ΔS is
negative.
B decay for b emission results in
neutron to proton
Isotopes have the same number of protons, but different numbers of
neutrons
Gas to solid is
non spontaneous
CF4 has polar bonds but is
non-polar overall.
Mass defect in nuclei is a direct result of the conversion of some nuclear mass to energy, called
nuclear binding energy.
x decay can be used to result in
nutreon to proton
As you go down a column in the periodic table, size increases because
of the addition of another electron shell and electron shielding.
Entropy (ΔS) refers to the state of
order or disorder.
losing electrons from left to right makes it more
organized
The titrand is the
original solution with an unknown concentration
strongest reducing agent is the one that is getting
oxidized if you flip the equation completely
The solubility of a gas is directly proportional to its
partial pressure
Heat and work are examples of
path (non-state) functions.
nitrogen can bond to fewer atoms than
phosphorus
Which of the following pieces of equipment would be best to measure and transfer 8.7 mL of a solution from an Erlenmeyer into a test tube?
pipet
As something becomes less organized (from a solid → liquid → gas), ΔH and ΔS is
positive.
A path function is a
property in which the process matters. Path functions depend on the transition or change of the state. Heat and work are examples of path (non-state) functions.
a base
proton acceptor
a base is defined as a
proton acceptor.
An acid is defined as a
proton donor
an acid
proton donor
B decay(positron emission) and electron capture both result in
proton to neutron
Crystallization is used to
purify solid compounds on the basis of differences in solubility.
Which of the following scenarios best illustrates Boyle's Law?
pushing a balloon
ΔH and ΔS are positive, this reaction will be ____________ at a high temperature.
spontaneous
Enthalpy, volume, mass and Gibbs free energy are all
state functions.
Weak bases have a
strong conjugate acid.
Weak acids have a
strong conjugate base.
Hydrogen bonds are
stronger intermolecular forces. This liquid would not evaporate as easily.
one with the highest pKb is the one with the
strongest base
The bond length between two atoms is equal to the
sum of the atomic radii of the two atoms.
What is the rate constant of a first-order reaction with a half-life of 5 minutes?
t 1/2= ln(2)/k Convert to seconds then do 300s=.693/k which is K= .693/300s Ln(2) is constant .693
half life of a first order reaction
t1/2=0.693/k
Entropy increases with
temperature
the only thing that can change Kc is
temperature, as Kc increases temp decreases.
Double bonds are stronger
than single bonds, and triple bonds are stronger than double bonds.
Oxoacids are acids
that contain oxygen
As the atoms become larger with a greater mass,
the Van der Waals forces increase, and boiling point rises.
As PKA goes down
the acid strength goes up
The group 2 elements, alkaline earth metals, also react with water. However, they do not react as vigorously as
the alkali metals.
Pressure is directly proportional to
the amount of the gas sample. (Moles)
In an electrolytic cell
the cathode is the negative electrode
The more moles a gas has ,
the higher its entropy.
the weaker the intermolecular force,
the higher the volatility.
Adding acid to water ensures that
the large volume of water will absorb the heat produced and prevents splashing.
The higher the molar solubility is,
the larger the Ksp value will be.
In an ionic compound, which element is losing electrons?
the metal
what occurs if T is increased for an Endothermic Reaction or T is decreased for an Exothermic reaction.
the reaction shifts to the right
the energy diagram of a reversible exothermic reaction says that
the reverse reaction has a larger than the forward reaction.
The smaller the atomic radii,
the smaller the bond length
the weaker the acid the
the stronger the conjugate base
boiling point
the temperature at which the vapor pressure of the liquid equals the surrounding pressure
Distillation
used to separate two liquids in a solution
Decreasing/increasing pressure only results in
vertical movement of the substance
A spontaneous electrochemical cell is a
voltaic or galvanic cell.
The group 1 elements, alkali metals, react vigorously with
water to produce hydrogen gas.
Always add acid to
water, never the other way around.
HF is a
weak electrolyte.
London dispersion forces are
weak intermolecular forces that arise from instantaneous dipoles in molecules without dipoles
sublime
when a compound has a vapor pressure higher than atmospheric pressure
Weak electrolyte
will have the lowest amount of ions in solution and will have the lowest electrical conductivity.
The reaction with the lowest activation energy, the difference in energy between the reactant and the transition state or the highest point along the reaction path,
will occur the fastest.
As the temperature increases, the disorder among the particles increases as solids begin to melt and liquids begin to vaporize.
.
Describe the reaction below: PCl3(g) + Cl2(g)→ PCl5(g) ; ΔHf = -87.9 kJ/mol
(ΔG<0) bc the number is negative, H will be less than 0
monoatomic gases
*noble gases* are monoatomic gases: He, Ne, Ar, Kr, Xe, Rn
Beta Decay
0/-1 e
The units are M·s-1, or M1·s-1. To find the reaction order, add the exponents and take the absolute value:
1 + (-1) = 0 This is a zero-order reaction.
second order reaction, y-axis is
1/con, slope is k
the third energy level can hold
18 electrons
first energy level can hold
2 electrons
A sample of an ideal gas at 25oC and 1 atm has a volume of 1.2 L. What will be the volume of the same sample of gas at 0.5 atm pressure and 25oC?
2.4, bc if pressure is decreased by half, volume will double.
Uranium-235 is a radioactive nuclide that decays by alpha emission. What is the product of decay of Uranium-235?
235U92-----> 4he2+231th90
the fourth energy level can hold
32 electrons
Alpha Decay
4/2 He
Strong acid/strong base has a pH of
7
Strong acid and strong base will have a pH of
7 at the equivalence point.
the second energy level can hold
8 electrons
Boyle's Law
A principle that describes the relationship between the pressure and volume of a gas at constant temperature
colligavtive property
A. Vapor pressure B. Freezing point C. Osmotic pressure D. Boiling point
In which instance is a gas most likely to behave ideally?
At high temperatures and low pressures, because the molecules are far apart and not likely to interact.
What is the temperature at which 64 g of O2 will occupy a volume of 8.2 L at 760 Torr?
Convert O2 to moles Then use ideal gas pressure equation which is T=PV/nR P is 1 atm since it was not stated V is volume N is moles of O2 and R is constant .082
The temperature dependence of spontaneity is given by:
Delta G= Delta H- Temp Delta S
The second law of thermodynamics deals with the spontaneity of the change of matter in terms of entropy (S). A change is spontaneous if
Delta S surrounding + Delta S system is more than 0
A standard voltaic cell is constructed using Cu metal in 1.0 M Cu(NO3)2(aq) and an unknown metal in a 1.0 M solution of its nitrate salt. The cell voltage is 0.47 V when the Cu half-cell is the cathode. What is the standard reduction potential of the unknown metal? EoCu2+/Cu = 0.34 V
Ecell= E red + E ox Plug values in .47v=.34+E ox Eoc=.13v Turn into a negative for Ered= -.13V
ΔH
Enthlapy change
A spontaneous process is one where ΔG < 0, or when ΔH < 0 and ΔS > 0 according to the equation
G=H-Ts
The enthalpy change can be calculated from bond energies using the following equation:
H= H bond broken - H bonds formed H bond is the rectants and H bond formed is the products
Strong acids are
HCl, HBr, HI, HNO3, H2SO4, HClO4
If pressure is decreased while temperature is constant, there are three possibilities
Solid to gas: Sublimation Liquid to solid: Crystallization Liquid to gas: Vaporization
Why does a nucleus weigh less than the sum of its neutrons and protons?
Some of the nucleus's mass gets converted into energy to hold the nucleus together
A change is spontaneous if
Surrounding + System is less than 0
1 mol of HNO3 is dissolved in 54.0 grams of H2O. What is the mole fraction of HNO3?
The equation for mole fraction is: mol fraction= mol of component/ total mol of all compounds Convert to moles than do 1 mole hno3/1mol hno3+ 3 mol of h2o
Which of the following solutions has the lowest freezing point?
The one that has the highest ions if all molarity given is the same
Equilibrium expression equation
The product side of the reaction is placed on top, and the reactant side is on the bottom of the expression. The coefficients become the exponents for their respective reactants in the equilibrium constant expression.
Which of these kinetic molecular theory assumptions is true of ideal gases?
The volume of individual gas molecules is negligible
A Lewis acid can be described as a species that
accepts electrons
pKa is the
acid strength
To get the bond order you would do
all all doubles single bond is 1 double bond is 2 then divide by how many single bonds and double bonds there are (in 1s)
What kind of radiation can lab coats protect against?
alpha particles
Because a proton is converting into a neutron, the atomic mass stays the same but the
atomic number decreases by one.
Ionization energy is a result of
atomic size.
The central atom that can most easily accept an electron pair is going to be the
best Lewis acid.
During a titration experiment, the titrant is placed in which of the following?
buret
third row (n=3) of the periodic table the elements are
capable of expanding their valence shell and breaking the octet rule.
Doubling the volume at constant temperature would
decrease the pressure by half.
ionization energy trend
decreases down a group, increases across a period
entropy
described as the measure of disorder, or randomness, in a system.
Distillation separates based on
differences in boiling point
allotrope
different structural forms of the same element
Which process would be used to separate two miscible liquids?
distillation
If the pressure is decreased by half, the volume will .
double
triple bonds are stronger than
double bonds
Ionic bonds are stronger than
intermolecular forces. This liquid would not evaporate as easily.
A spontaneous reaction can produce an
increase in entropy.
As pressure of the gas increases, the solubility of the gas
increases
As temperature of the solution decreases, the solubility of the gas
increases
the strength of the acid increases as the number of oxygens
increases
As pressure of the gas increases, the solubility of the gas
increases.
As temperature of the solution decreases, the solubility of the gas
increases.
the strength of the acid increases as the number of oxygens
increases.
Bond length decreases with
increasing bond order.
Average kinetic energy increases with
increasing temperature.
Enthalpy also changes with
increasing temperatures.
In a covalent substance, melting breaks
intermolecular bonds
n a covalent substance, melting breaks
intermolecular bonds
what occurs if T is decreased for an Endothermic Reaction or T is increased for an Exothermic reaction.
reaction shifts to left
conjugate acid
received proton
An oxidizing agent gets_______. A reducing agent gets _______.
reduced. oxidized.
Diamagnetic means
repelled from magnetic fields. They have all their electrons paired in their orbitals.
a beta particle
represented by 0 a -1
An alpha particle
represented by 4 a 2
Average kinetic energy of gaseous molecules depend
s on absolute temperature. Because the two gases are at the same temperature, their average kinetic energies are the same.
For adding and subtracting, the answer must have the
same number of decimal places as the measurement with the fewest number of decimal places.
Which best describes an isotope?
same number of protons but different number of neutrons
Filtration is an effective technique to
separate a solid from a liquid
crystalline solid
sharp and well defined melting temperature
atom with the smallest atomic size is the one with the
shortest bond length
Double bonds are stronger than
single bonds
If ionization energy is high and electron affinity is high, atomic radii would be
small for both atoms.
Atomic size gets
smaller UP and to the RIGHT of the periodic table.
The partial pressure is tripled, so the
solubility will triple.
Transition metals can form brightly colored compounds because
their d orbitals are unfilled or half filled.
If the partial pressure of the gas is increased,
there will be more interactions between the gas and the solution, increasing solubility.
Pure elemental gases are covalently bonded and are non-polar. As a result,
they have low intermolecular forces acting on the molecules.
A trigonal planar geometry will have
three areas of electron bonding pairs with no non-bonding electron lone pairs.
The electrons flow from the anode
to the cathode
Atomic radius is smallest at the
top right of the periodic table.
beaker
used for stirring, mixing, and heating solutions
Which of the following gases will have the greatest density at STP? A. Cl2 (7%) B. N2O (1%) C. Ar (7%) D. SO3 (84%) E. CO2 (1%)
you do PV=nRT As molecular weight goes up, density goes up.
A gas filled balloon contains triptane gas (C7H16 ; MM = 100 g/mol) and another unknown gas. This balloon develops a pinhole leak. The unknown gas effuses out of the balloon FIVE times as fast as triptane gas. Which of the following could be the unknown gas?
you would do 5= SQ 100/molar mass x then you do 25=100/molarmass then its simple math of 4g/mol H