Chemistry: A Molecular Approach, 3e (Tro)
Chapter 13 Chemical Kinetics
Multiple Choice Questions
1) Identify the methods used to monitor a reaction as it occurs in the reaction flask.
A) polarimeter
B) spectrometer
C) pressure measurement
D) none of the above
E) all of the above
2) Given the following balanced equation, determine the rate of reaction with respect to [NOCl].
2 NO(g) + Cl2(g) → 2 NOCl(g)
A) Rate = –
B) Rate = +
C) Rate = –
D) Rate = –
E) It is not possible to determine without more information.
3) Given the following balanced equation, determine the rate of reaction with respect to [H2].
N2(g) + 3 H2(g) → 2 NH3(g)
A) Rate = +
B) Rate = –
C) Rate = +
D) Rate = –
E) It is not possible to determine without more information.
4) Given the following balanced equation, determine the rate of reaction with respect to [NH3].
N2(g) + 3 H2(g) → 2 NH3(g)
A) Rate = +
B) Rate = –
C) Rate = +
D) Rate = –
E) It is not possible to determine without more information.
5) Given the following balanced equation, determine the rate of reaction with respect to [N2].
N2(g) + 3 H2(g) → 2 NH3(g)
A) Rate = +
B) Rate = –
C) Rate = +
D) Rate = –
E) It is not possible to determine without more information.
6) Write a balanced reaction for which the following rate relationships are true.
Rate = – = =
A) 2 N2O5 → 4 NO2 + O2
B) 4 NO2 + O2 → 2 N2O5
C) 2 N2O5 → NO2 + 4 O2
D) NO2 + O2 → N2O5
E) N2O5 → NO2 + O2
7) Write a balanced reaction for which the following rate relationships are true.
Rate = = = –
A) N2 + O2 → N2O
B) 2 N2O → 2 N2 + O2
C) N2O → N2 + 2 O2
D) N2O → N2 + O2
E) 2 N2 + O2 → 2 N2O
8) Give the characteristic of a first order reaction having only one reactant.
A) The rate of the reaction is not proportional to the concentration of the reactant.
B) The rate of the reaction is proportional to the square of the concentration of the reactant.
C) The rate of the reaction is proportional to the square root of the concentration of the reactant.
D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant.
E) The rate of the reaction is directly proportional to the concentration of the reactant.
9) Give the characteristic of a zero order reaction having only one reactant.
A) The rate of the reaction is not proportional to the concentration of the reactant.
B) The rate of the reaction is proportional to the square of the concentration of the reactant.
C) The rate of the reaction is proportional to the square root of the concentration of the reactant.
D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant.
E) The rate of the reaction is directly proportional to the concentration of the reactant.
10) Give the characteristic of a second order reaction having only one reactant.
A) The rate of the reaction is not proportional to the concentration of the reactant.
B) The rate of the reaction is proportional to the square of the concentration of the reactant.
C) The rate of the reaction is proportional to the square root of the concentration of the reactant.
D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant.
E) The rate of the reaction is directly proportional to the concentration of the reactant.
11) What is the overall order of the following reaction, given the rate law?
NO(g) + O3(g) → NO2(g) + O2(g) Rate = k[NO][O3]
A) 1st order
B) 2nd order
C) 3rd order
D) 1 order
E) 0th order
12) What are the units of k in the following rate law?
Rate = k[X][Y]2
A)
B)
C) M2 s
D)
E)
13) What are the units of k in the following rate law?
Rate = k[X]2[Y]2
A)
B)
C) M2 s
D)
E)
14) What are the units of k in the following rate law?
Rate = k[X][Y]
A)
B) Ms
C)
D)
E)
15) What are the units of k in the following rate law?
Rate = k[X]
A)
B) Ms
C)
D)
E)
16) What are the units of k in the following rate law?
Rate = k[X]0[Y]0
A)
B) Ms
C) M-1s-1
D)
E)
17) What are the units of k in the following rate law?
Rate = k[X][Y]1/2
A) M/s
B) M-1s-1
C) M1/2s-1
D) M-1/2s-1
E) M-1s-1/2
18) What are the units of k in the following rate law?
Rate = k[X]2
A) Ms-1
B) Ms
C) M-1s-1
D) M-2s-1
E) M2s-1
19) Determine the rate law and the value of k for the following reaction using the data provided.
CO(g) + Cl2(g) → COCl2(g) [CO]i (M) [Cl2]i (M) Initial Rate (M-1s-1)
0.25 0.40 0.696
0.25 0.80 1.97
0.50 0.80 3.94
A) Rate = 11 M-3/2s-1 [CO][Cl2]3/2
B) Rate = 36 M-1.8s-1 [CO][Cl2]2.8
C) Rate = 17 M-2s-1 [CO][Cl2]2
D) Rate = 4.4 M-1/2s-1 [CO][Cl2]1/2
E) Rate = 18 M-3/2s-1 [CO]2[Cl2]1/2
20) Determine the rate law and the value of k for the following reaction using the data provided.
S2O82⁻(aq) + 3 I⁻(aq) → 2 SO42⁻(g) + I3⁻(aq) [S2O82⁻]i (M) [I⁻]i (M) Initial Rate (M-1s-1)
0.30 0.42 4.54
0.44 0.42 6.65
0.44 0.21 3.33
A) Rate = 120 M-2s-1 [S2O82⁻]2[I⁻]
B) Rate = 36 M-1s-1 [S2O82⁻][I⁻]
C) Rate = 86 M-2s-1 [S2O82⁻][I⁻]2
D) Rate = 195 M-3s-1 [S2O82⁻]2[I⁻]2
E) Rate = 23 M-1/2s-1 [S2O82⁻][I⁻]1/2
21) Determine the rate law and the value of k for the following reaction using the data provided.
NO2(g) + O3(g) → NO3(g) + O2(g) [NO2]i (M) [O3]i (M) Initial Rate (M-1s-1)
0.10 0.33 1.42
0.10 0.66 2.84
0.25 0.66 7.10
A) Rate = 1360 M-2.5s-1[NO2]2.5[O3]
B) Rate = 227 M-2.5s-1[NO2][O3]2.5
C) Rate = 43 M-1s-1[NO2][O3]
D) Rate = 430 M-2s-1[NO2]2[O3]
E) Rate = 130 M-2s-1[NO2][O3]2
22) Determine the rate law and the value of k for the following reaction using the data provided.
2 NO(g) + O2(g) → 2 NO2(g) [NO]i (M) [O2]i (M) Initial Rate (M-1s-1)
0.030 0.0055 8.55 x 10-3
0.030 0.0110 1.71 x 10-2
0.060 0.0055 3.42 x 10-2
A) Rate = 57 M-1s-1[NO][O2]
B) Rate = 3.8 M-1/2s-1[NO][O2]1/2
C) Rate = 3.1 × 105 M-3s-1[NO]2[O2]2
D) Rate = 1.7 × 103 M-2s-1[NO]2[O2]
E) Rate = 9.4 × 103 M-2s-1[NO][O2]2
23) Carbon-14 has a half-life of 5720 years and this is a first order reaction. If a piece of wood has
converted 75% of the carbon-14, then how old is it?
A) 11440 years
B) 2375 years
C) 4750 years
D) 4290 years
E) 1430 years
24) Carbon-14 has a half-life of 5720 years and this is a first order reaction. If a piece of wood has
converted 25% of the carbon-14, then how old is it?
A) 11440 years
B) 2375 years
C) 4750 years
D) 4290 years
E) 1430 years
25) Which of the following represents the integrated rate law for a first-order reaction?
A) = – kt
B) – = kt
C) [A]t – [A]o = – kt
D) k = Ae(-Ea/RT)
E) = ( ) + lnA
26) Which of the following represents the integrated rate law for a second-order reaction?
A) = – kt
B) – = kt
C) [A]t – [A]o = – kt
D) k = Ae(-Ea/RT)
E) = ( ) + lnA
27) Which of the following represents the integrated rate law for a zeroth-order reaction?
A) = – kt
B) – = kt
C) [A]t – [A]o = – kt
D) k = Ae(-Ea/RT)
E) = ( ) + lnA
28) What data should be plotted to show that experimental concentration data fits a first-order reaction?
A) 1/[reactant] vs. time
B) [reactant] vs. time
C) ln[reactant] vs. time
D) ln(k) vs. 1/T
E) ln(k) vs. Ea
29) What data should be plotted to show that experimental concentration data fits a second-order
reaction?
A) ln[reactant] vs. time
B) [reactant] vs. time
C) ln(k) vs. 1/T
D) 1/[reactant] vs. time
E) ln(k) vs. Ea
30) What data should be plotted to show that experimental concentration data fits a zeroth-order
reaction?
A) ln[reactant] vs. time
B) 1/[reactant] vs. time
C) ln(k) vs. 1/T
D) ln(k) vs. Ea
E) [reactant] vs. time
12
31) Which of the following statements is FALSE?
A) The average rate of a reaction decreases during a reaction.
B) It is not possible to determine the rate of a reaction from its balanced equation.
C) The rate of zero order reactions are not dependent on concentration.
D) The half life of a first order reaction is dependent on the initial concentration of reactant.
E) None of the statements are FALSE.
32) Which of the following statements is FALSE?
A) The half life of a zero order reaction is dependent on concentration.
B) The half life of a second order reaction is not dependent on concentration.
C) The rate of second order reactions is dependent on concentration.
D) The rate of a first order reaction is dependent on concentraion.
E) None of the statements are FALSE.
33) The rate constant for the first-order decomposition of N2O is 3.40 s-1. What is the half-life of the
decomposition?
A) 0.491 s
B) 0.204 s
C) 0.236 s
D) 0.424 s
E) 0.294 s
34) The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI
is 0.67 M. What is the rate constant for this reaction?
A) 1.0 × 10-2 M-1s-1
B) 4.5 × 10-2 M-1s-1
C) 9.7 × 10-2 M-1s-1
D) 2.2 × 10-2 M-1s-1
E) 3.8 × 10-2 M-1s-1
35) The half life for the decay of radium is 1620 years. What is the rate constant for this first-order
process?
A) 4.28 × 10-4 yr-1
B) 1.12 × 10-4 yr-1
C) 2.33 × 10-4 yr-1
D) 8.91 × 10-4 yr-1
E) 6.17 × 10-4 yr-1
36) The first-order decomposition of cyclopropane has a rate constant of 6.7 x 10-4 s-1. If the initial
concentration of cyclopropane is 1.33 M, what is the concentration of cyclopropane after 644 s?
A) 0.43 M
B) 0.15 M
C) 0.94 M
D) 0.86 M
E) 0.67 M
37) The first-order decomposition of N2O at 1000 K has a rate constant of 0.76 s-1. If the initial
concentration of N2O is 10.9 M, what is the concentration of N2O after 9.6 s?
A) 7.4 × 10-3 M
B) 1.0 × 10-3 M
C) 1.4 × 10-3 M
D) 3.6 × 10-3 M
E) 8.7 × 10-3 M
38) The second-order decomposition of HI has a rate constant of 1.80 x 10-3 M-1s-1. How much HI
remains after 27.3 s if the initial concentration of HI is 4.78 M?
A) 4.55 M
B) 0.258 M
C) 3.87 M
D) 2.20 M
E) 2.39 M
39) Derive an expression for a “1/3-life” for a first-order reaction.
A)
B)
C)
D)
E)
40) Derive an expression for a “1/4-life” for a first-order reaction.
A)
B)
C)
D)
E)
15
41) The first-order decay of radon has a half-life of 3.823 days. How many grams of radon remain after
7.22 days if the sample initially weighs 250.0 grams?
A) 4.21 g
B) 183 g
C) 54.8 g
D) 76.3 g
E) 67.5 g
42) The first-order decay of radon has a half-life of 3.823 days. How many grams of radon decomposes
after 5.55 days if the sample initially weighs 100.0 grams?
A) 83.4 g
B) 16.6 g
C) 50.0 g
D) 36.6 g
E) 63.4 g
43) The first-order decomposition of N2O5 at 328 K has a rate constant of 1.70 × 10-3 s-1. If the initial
concentration of N2O5 is 2.88 M, what is the concentration of N2O5 after 12.5 minutes?
A) 0.124 M
B) 0.805 M
C) 2.82 M
D) 0.355 M
E) 0.174 M
44) The second-order decomposition of NO2 has a rate constant of 0.255 M-1s-1. How much NO2
decomposes in 4.00 s if the initial concentration of NO2 (1.00 L volume) is 1.33 M?
A) 1.8 mol
B) 0.85 mol
C) 0.48 mol
D) 0.77 mol
E) 0.56 mol
45) For a reaction, what generally happens if the temperature is increased?
A) a decrease in k occurs, which results in a faster rate
B) a decrease in k occurs, which results in a slower rate
C) an increase in k occurs, which results in a faster rate
D) an increase in k occurs, which results in a slower rate
E) there is no change with k or the rate
46) Identify the rate-determining step.
A) the slowest step
B) the faster step
C) the fast step
D) always the last step
E) always the second step
47) The first-order rearrangement of CH3NC is measured to have a rate constant of 3.61 x 10-15 s-1 at
298 K and a rate constant of 8.66 × 10-7 s-1 at 425 K. Determine the activation energy for this reaction.
A) 160. kJ/mol
B) 240. kJ/mol
C) 417 kJ/mol
D) 127 kJ/mol
E) 338 kJ/mol
48) A reaction is followed and found to have a rate constant of 3.36 × 104 M-1s-1 at 344 K and a rate
constant of 7.69 M-1s-1 at 219 K. Determine the activation energy for this reaction.
A) 23.8 kJ/mol
B) 42.0 kJ/mol
C) 11.5 kJ/mol
D) 12.5 kJ/mol
E) 58.2 kJ/mol
49) A reaction is found to have an activation energy of 108 kJ/mol. If the rate constant for this reaction
is 4.60 × 10-6 s-1 at 275 K, what is the rate constant at 366 K?
A) 12 s-1
B) 1.7 s-1
C) 0.58 s-1
D) 5.4 × 10-5 s-1
E) 1.9 × 10-4 s-1
50) A reaction is found to have an activation energy of 38.0 kJ/mol. If the rate constant for this reaction
is 1.60 × 102 M-1s-1 at 249 K, what is the rate constant at 436 K?
A) 2.38 × 105 M-1s-1
B) 1.26 × 103 M-1s-1
C) 7.94 × 104 M-1s-1
D) 4.20 × 105 M-1s-1
E) 3.80 × 104 M-1s-1
17
51) If the activation energy for a given compound is found to be 42.0 kJ/mol, with a frequency factor of
8.0 × 1010 s-1, what is the rate constant for this reaction at 298 K?
A) 2.9 × 10-4 s-1
B) 7.4 × 10-4 s-1
C) 1.4 × 109 s-1
D) 4.6 × 10 5 s-1
E) 3.5 × 103 s-1
52) If the activation energy for a given compound is found to be 103 kJ/mol, with a frequency factor of
4.0 × 1013 s-1, what is the rate constant for this reaction at 398 K?
A) 1.2 s-1
B) 8.2 s-1
C) 3.9 × 1010 s-1
D) 1.7 × 1010 s-1
E) 2.5 × 107 s-1
53) Given the following proposed mechanism, predict the rate law for the overall reaction.
A2 + 2B → 2AB (overall reaction)
Mechanism
A2 ⇌ 2A fast
A + B → AB slow
A) Rate = k[A][B]
B) Rate = k[A2][B]
C) Rate = k[A2][B]1/2
D) Rate = k[A2]
E) Rate = k [A2]1/2[B]
54) Which of the following statements is TRUE?
A) The rate constant does not depend on the activation energy for a reaction where the products are
lower in energy than the reactants.
B) A catalyst raises the activation energy of a reaction.
C) Rate constants are temperature dependent.
D) The addition of a homogeneous catalyst does not change the activation energy of a given reaction.
E) None of the above are true.
55) Identify an homogeneous catalyst.
A) SO2 over vanadium (V) oxide
B) Pd in H2 gas
C) Pt with methane
D) H2SO4 with concentrated HCl
E) N2 and H2 catalyzed by Fe
56) Identify an heterogeneous catalyst.
A) CFCs with ozone
B) Pd in H2 gas
C) KI dissolved in H2O2
D) H2SO4 with concentrated HCl
E) H3PO4 with an alcohol
57) In the hydrogenation of double bonds, a catalyst is needed. In the first step, the reactants must come
into contact with a metal surface. This step is known as ________.
A) adsorption
B) diffusion
C) reaction
D) desorption
E) none of the above
58) In the hydrogenation of double bonds, a catalyst is needed. In the last step, the reactants must
escape from the surface into the gas phase. This step is known as ________.
A) adsorption
B) diffusion
C) reaction
D) desorption
E) none of the above
59) Biological catalysts that increase the rates of biochemical reactions are known as ________.
A) substrates
B) inhibitors
C) enzymes
D) binders
E) trumanettes
Algorithmic Questions
1) Given the following balanced equation, determine the rate of reaction with respect to [SO2].
2 SO2(g) + O2(g) → 2 SO3(g)
A) Rate = –
B) Rate = +
C) Rate = –
D) Rate = +
E) It is not possible to determine without more information.
2) Given the following balanced equation, determine the rate of reaction with respect to [O2].
2 SO2(g) + O2(g) → 2 SO3(g)
A) Rate = –
B) Rate = +
C) Rate = –
D) Rate = +
E) It is not possible to determine without more information.
3) Given the following balanced equation, determine the rate of reaction with respect to [SO3].
2 SO2(g) + O2(g) → 2 SO3(g)
A) Rate = –
B) Rate = +
C) Rate = –
D) Rate = –
E) It is not possible to determine without more information.
4) Given the following balanced equation, determine the rate of reaction with respect to [O2].
2 O3(g) → 3 O2(g)
A) Rate = +
B) Rate = –
C) Rate = +
D) Rate = –
E) It is not possible to determine without more information.