AP CHEM MC
what is the rate constant, k, for the decomposition reaction
0.012 day-
a student mixes 40 ml of 0.10 M hbr with 60 ml of 0.10 M KOH at 25c. what is the oh- of the resulting solution
0.020M
what is the values of kp for the reaction at 690 k
0.050
what was the initial rate of decrease in (y)
5.6 e -3 mol L- s-
if a new experiment is conducted with m and n each 2 e-3 molar, the reaction rate will increase by a factor of
8
if 87.5 percent of a sample of pure 131I decays in 24 days, what is the half-life of 131I
8 days
in which of the following compounds is the mass ratio of chromium to oxygen closest to 1.62 to 1.00
CrO2
which of the following describes how the measured pressure in the reaction vessel will change and why it will change that way as the reaction system approaches equilibrium at constant temperature
The pressure will decrease because Q>kc
the reason for the abruptness of this color change is that
a large change in pH occurs near the endpoint of the titration
which of the following mixtures is a buffer with a pH of approximately 3
a mixture of 100 ml of 0.1 M hc3h5o3 and 50 ml of 0.1 M NaOH
of the following species, whcih has the greatest concentration in a 1.0 M solution of acid 1 at equilibrium
acid 1
which of the four acids listed in the table is hydrochloric acid
acid 2
which of the following will most likely increase the rate of the reaction represented above
adding a heterogeneous catalyst to the reaction
if equal volumes of the four acids at a concentration of 0.50 M are each titrated with a strong base, which will require the greatest volume of base to reach the equivalence point
all the acids will require the same volume of base
which of the following best helps to account for the fact that the f- ion is smaller than the o2- ion
ar, because of its higher effective nuclear charge
which of the following accounts for the observation that the pH of pure water at 37c is 6.8
at 37c the autoionization constant for water, kw, is larger than it is at 25c
that are present in significant concentrations int he solution at point U in the titration
b) 1OH- 2 A- 3 Na+
which of the following reaction profiles best corresponds to the proposed mechanism above
b) first curve highest then dips and 2nd slightly less and end point is lower than start point
the mass spectrum of the element sb is most likely represents by which of the following
b) more on 121 some on 123
a 27.0 gram sample of an unknown hydrocarbon was burned in excess oxygen to form 88.0 grams of carbon dioxide and 27.0 grams of water. what is a possible molecular formula of the hydrocarbon
c4h6
whcih fot eh following correctly identifies the species associated with peak x and provides a valid justification
ca 2+ becuase its nucleus has two more protons than the nucleus of Ar has
which of the elements above has the largest atomic radius
cs
which of the elements above has the lowest ionization energy
cs
which of the follwoing equations represents the chemical reaction that accounts for the fact that acid was added but there was no detectable change in pH
h3o+ + c2h3o2- = hc2h3o2 +h20
when combined in equimolar amounts, results in a buffer with a pH closest to 7.5
hclo and clo-
factors that affect the rate of a chemical reaction include which of the following
i, ii, iii
mixtures that would be considered buffers include which of the following
ii ) .10MHF+.10MNaF
which of the following observations would provide evidence that the spectrum is consistent with the atomic model of the element
in its compounds, the element tends to form ions with a charge of +1
The student collects the precipitate by filtration, dries it, and records the data shown below
kcl
which of the following changes will increase the amount of BaO2 in the vessel
lowering the temperature
based on the data, the peak at 26 amu represents an isotope of which of the following elements
mg with 14 neutrons
atoms of an element, X, have the electronic configuration shown above. the compound most likely formed with magnesium
mg3x2
which of the following elements has the mass spectrum on the right
mo
which of the following will occur as the system approaches equilibrium
more hi will be produced because Q<kc
which of teh following statements best accounts for the peak in oxygen spectrum being to the right of the peak in the nitrogen spectrum
nitrogen atoms have a smaller nuclear charge than oxygen atoms
which of the following represents an electron configuration that corresponds to the valence electrons of an element for which there is an especially large jump between the second and third ionization energies
ns2
which of the following best explains this observation
one of the reactants binds on the surface of Pd, which introduces an alternative reaction pathway with a lower activation energy
for which of teh equilibrium systems represented below will the amount of product(s) at equilibrium increase if the volume of the reaction vessel is increase at a constant temperature
pcl5=pcl3+cl2
which of the following correctly identifies the 1s peak for the F atoms and provides an appropriate explanation
peak x, because f has a greater nuclear charge than C
at equilibrium, which of the following si true about the concentrations of the gasses
r=z > Q
which of the following rate laws for the overall reaction corresponds to the proposed mechanism
rate=k(cl)(o3)
which of the following rate laws is consistent with this mechanism
rate=k(no2)(f2)
which of the following is the rate law for the overall reaction that is consistent with the proposed mechanism
rate=k(no2)2
the data in the table on the right were obtained for the reaction x +y =z. which of the following is the rate law for the reaction
rate=k(y)2
the masses of carbon and hydrogen in samples of four pure hydrocarbons are given on the right. the hydrocarbon in which samples has the same empirical formula as propene, c3h6
sample B 72gC, 12 gH
if a sample of a compound contains 3.21 g of sulfur and 11.4 g of flouring. which of the following represents the empirical formula of the compound
sf6
what will the student obtain for the calculated concentration of the acid
slightly more than 0.0800 M
if a pure sample of an oxide of sulfur contains 40. percent sulfur and 60. percent oxygen by mass, then the empirical formula of the oxide is
so3
relatively slow rates of chemical reaction are associated with which of the following
strong bonds in reactant molecules
the most probable explanation for this observation is taht
substance b is not involved in the rate-determined step of the mechanism, but it is involved in the subsequent steps
which of the following best explains what happens to the pH of the mixture when a few drops of 1.0 M HNO3 are added
the Ph of the mixtres stays about the same, because the conjugate base of acid 1 reacts with the added H3O+ ions
the mass spectrum of element x is presented in the diagram on the above on the left. based on the spectrum, which of the following can be concluded about element x
the atomic mass of x is between 90 and 92
which of the following correctly compares periodic properties of two elements and provides an accurate explanation for that difference
the atomic radius of cl is smaller than that of S because cl has a larger nuclear charge than S does
what change will be caused by the addition of a small amount of HCL to a solution containing fluoride ions and hydrogen fluoride
the concentration of fluoride ion will decrease and the concentration of hydrogen fluoride will increase
which of teh following correctly describes the reaction
the decomposition of n2o5 is a first-order reaction
which of the following is the most likely explanation for the large difference between the second and third ionization energies
the electron removed during the third ionization is, on average, much closer to the nucleus than the first two electrons removes were
which of the following best explains how the spectrum is consisten with the electron shell model
the electrons int eh 2p sublevel have the smallest binding energy
a proposed mechanism for destruction of ozone gas in the stratosphere is represented above. which of the following is evidence that the mechanism is occurring
the presence of cl increases the rate of the overall reaction
which of the following statements is true
the rate law that is consistent with the mechanism is rate=k(no2)2(o2)
according to the rate law for the reaction, an increase in the concentration of hydronium ion by a factor of two has what effect on the rate of the overall reaction
the rate of reaction also increases by a factor of two
which of the following best describes what will happen to the reaction immediately after additional iodine gas is added to the system
the rate of the forward reaction becomes greater than the rate of the reverse reaction
which of the following was true for the system between time t1 and time t2
the rates of the forward and reverse reactions were equal
which of the following best helps to explain why the electron affinity of br is larger than that of I
there is a greater attraction between an added electron and nucleus in Br than in I
which of the following best helps to explain the deviation of the first ionization energy of oxygen from the overall trend
there is repulsion between paired electrons in oxygen's 2p orbitals
which of the following changes will most likely increase the rate of reaction between li and water
using a 0.35 g sample of Li cut into small pieces
whcih of the following best helps explain why the electron eqativity of Cl is less than that of F
when cla dn f form bonds with other atoms, the cl bonding electrons are more shielded from the positive cl nucleus than the f bonding electrons are shielded from the positive F nucleus
which of the following is most likely the empirical formula of an oxide of element x
x2o3
what was the concentration of acetic acid in the vinegar if no other acid was present
0.800 M
at 25c aqueous solutions with a pH of 8 have a hydroxide ion concentration OH- of
1 e -6 M
a 0.10 M solution of a weak monoprotic acid has a pH equal to 4.0. the ionization constant, ka, of the acid is
1 e-7
when 200. ml of 2M NaOH is added to 500 ml of 1.0 M Hcl the PH of the resulting mixture is closest to
1.0
a 0.20 mol samples of mgcl2 and a 0.10 mol sample of KCl are dissolved in water and diluted to 500 ml. What is the concentration of Cl- in the solution
1.0 M
what is the values of the equilibrium constant for the following reaction at 25c: O2 + 4NO2=2N2O5
1/(95)^2
what fraction of a sample of pure 20O remains after 1.0 minute
1/16
what is the value of kc at this temperature if 0.00500 mol of n2o4 is present at equilibrium
12.5
which represents an atom in an excited state
1s22s22p53s2
which of the following ground-state electron configurations represents the atom taht has the lowest first-ionization energy
1s22s22p63s1
a 0.10 M solution of a weak monoprotic acid has a pH equal to 4.0. The ionization constant, Ka, of the acid is
1x10^-7
The volume of water that must be added to dilute 40 ml of 9.0 M HCl to a concentration of 6.0 M is closest to
20 ml
the colume of distilled water added to the original solution is closest to
270 ml
if teh reaction was first order with respect to X and second order with respect to Y, the initial rate of formation of Z in experiment 2 is
2R
based on the graph, the pka of the acid is closest to
4.0
what was the rate of disappearance of mno4- at the same time
4.0 e -4
the pka of hc3h5o3 is 3.08. what is the pH of the resulting solution
4.08
what is the h+ concentration in a 0.05 M hcn
5 e -6
which of the following is true at equilibrium
Co2>CO
at point R in the titration, whcih of the following species has the highest concentration
HA
According to the information in the table on the right, a 1 g sample of whcih of the following contains the greatest mass of oxygen?
MgO
at which point on the titration curve is A- closest to twice that of HA
T
for which acid is the value of the acid dissociation constant, ka, the smallest
acid 1
if equal masses of the following compounds undergo complete combustion, whcih will yield the greatest mass of CO2
benzene, c6h6
which of the elements above has the highest electronegativity
br
in 1.00 mol of potassium zirconium sulfate trihydrate, K4Zr(SO4)4 x 3 H2O, there are:
c) 4 x 6.02 e 23 potassium atoms
the amount of which of teh following species increases as the KOH is added
clo2-
which of the following graphs indicates that the rate of decomposition is second order in x
going up and 1/x