Chapter 12: Chemical Kinetics
1. The average rate of disappearance of ozone in the reaction is found to be
atm over a certain interval of time. What is the rate of appearance of during
this interval?
A)
atm/s
B)
atm/s
C)
atm/s
D)
atm/s
E)
atm/s
2. The balanced equation for the reaction of bromate ion with bromide ion in acidic solution is
given by:
At a particular instant in time, the value of is mol/L s. What is the
value of in the same units?
A)
B)
C)
D)
E)
3. Consider the reaction
What is the ratio of the initial rate of the appearance of water to the initial rate of
disappearance of oxygen?
A)
1 : 1
B)
2 : 1
C)
1 : 2
D)
2 : 2
E)
3 : 2
4. Consider the reaction:
At a certain instant the initial rate of disappearance of the oxygen gas is X. What is the value
of the appearance of water at the same instant?
A)
1.2 X
B)
1.1 X
C)
0.86 X
D)
0.58 X
E)
cannot be determined from the data
5. For the reaction , at a particular instant in time, the rate of the reaction
is 0.0223 M/s. What is the rate of change of A?
A)
–0.0223 M/s
B)
0.112 M/s
C)
–0.112 M/s
D)
–0.00446 M/s
E)
0.00446 M/s
6. Consider the reaction X → Y + Z
Which of the following is a possible rate law?
A)
Rate = k[X]
B)
Rate = k[Y]
C)
Rate = k[Y][Z]
D)
Rate = k[X][Y]
E)
Rate = k[Z]
7. Consider the following rate law:
How are the exponents n and m determined?
A)
by using the balanced chemical equation
B)
by using the subscripts for the chemical formulas
C)
by using the coefficients of the chemical formulas
D)
by educated guess
E)
by experiment
8. The following data were obtained for the reaction of NO with O2. Concentrations are in
molecules/cm3 and rates are in molecules/cm3s.
[NO]0
[O2]0
Initial Rate
1 1018
1 1018
2.0 1016
2 1018
1 1018
8.0 1016
3 1018
1 1018
18.0 1016
1 1018
2 1018
4.0 1016
1 1018
3 1018
6.0 1016
What is the rate law?
A)
Rate = k[NO][O2]
B)
Rate = k[NO][O2]2
C)
Rate = k[NO]2[O2]
D)
Rate = k[NO]2
E)
Rate = k[NO]2[O2]2
9. The reaction of with hydroxide ion proceeds with the formation of
.
The following data were obtained at 55°C.
[OH–]0
Initial Rate
Exp.
(mol/L)
(mol/L)
1
0.10
1.0 10–3
2
0.10
2.0 10–3
3
0.20
1.0 10–3
4
0.20
?
What will the initial rate (in mol/L·s) be in Experiment 4?
A)
3.0 10–3
B)
6.0 10–3
C)
9.0 10–3
D)
18 10–3
E)
none of these
10. For a reaction in which A and B react to form C, the following initial rate data were
obtained:
[A]
[B]
Initial Rate of Formation of C
(mol/L)
(mol/L)
(mol/L·s)
0.10
0.10
1.00
0.10
0.20
4.00
0.20
0.20
8.00
What is the rate law?
A)
Rate = k[A][B]
B)
Rate = k[A]2[B]
C)
Rate = k[A][B]2
D)
Rate = k[A]2[B]2
E)
Rate = k[A]3
11. Tabulated below are initial rate data for the reaction
Run
Initial
Rate (M/s)
1
0.01
0.01
0.01
0.01
1 10–5
2
0.01
0.02
0.01
0.01
2 10–5
3
0.02
0.02
0.01
0.01
8 10–5
4
0.02
0.02
0.02
0.01
8 10–5
5
0.02
0.02
0.02
0.02
8 10–5
The experimental rate law is:
A)
B)
C)
D)
E)
12. Tabulated below are initial rate data for the reaction:
2Fe(CN)63– + 2I– → 2Fe(CN)64– + I2
Run
[Fe(CN)63–]0
[I–]0
[Fe(CN)64–]0
[I2]0
Rate (M/s)
1
0.01
0.01
0.01
0.01
1 10–5
2
0.01
0.02
0.01
0.01
2 10–5
3
0.02
0.02
0.01
0.01
8 10–5
4
0.02
0.02
0.02
0.01
8 10–5
5
0.02
0.02
0.02
0.02
8 10–5
What is the value of k?
A)
107 M–5 s–1
B)
103 M–3 s–1
C)
10 M–2 s–1
D)
50 M–2 s–1
E)
none of these
A general reaction written as A + 2B → C + 2D is studied and yields the following data:
[A]0
[B]0
Initial [C]/t
0.150 M
0.150 M
8.00 10–3 mol/L·s
0.150 M
0.300 M
1.60 10–2 mol/L·s
0.300 M
0.150 M
3.20 10–2 mol/L·s
13. What is the order of the reaction with respect to B?
A)
0
B)
1
C)
2
D)
3
E)
4
14. What is the order of the reaction with respect to A?
A)
0
B)
1
C)
2
D)
3
E)
4
15. What is the overall order of the reaction?
A)
0
B)
1
C)
2
D)
3
E)
4
16. What is the numerical value of the rate constant?
A)
0.053
B)
1.19
C)
2.37
D)
5.63
E)
none of these (A-D)
17. Determine the initial rate of B consumption ([B]/t) for the first trial?
A)
8.00 10–3 mol/L·s
B)
1.60 10–2 mol/L·s
C)
3.20 10–2 mol/L·s
D)
4.00 10–3 mol/L·s
E)
none of these (A-D)
18. Determine the initial rate of C production ([C]/t) if [A] = 0.200 M and [B] = 0.500 M.
A)
4.74 10–2 mol/L·s
B)
2.37 10–1 mol/L·s
C)
1.19 10–1 mol/L·s
D)
8.23 10–2 mol/L·s
E)
none of these (A-D)
Consider the following data concerning the equation:
H2O2 + 3I– + 2H+ → I3– + 2H2O
[H2O2]
[I–]
[H+]
rate
I
0.100 M
5.00 10–4 M
1.00 10–2 M
0.137 M/sec
II.
0.100 M
1.00 10–3 M
1.00 10–2 M
0.268 M/sec
III.
0.200 M
1.00 10–3 M
1.00 10–2 M
0.542 M/sec
IV.
0.400 M
1.00 10–3 M
2.00 10–2 M
1.084 M/sec
19. The rate law for this reaction is
A)
rate = k[H2O2][I–][H+]
B)
rate = k[H2O2]2[I–]2[H+]2
C)
rate = k[I–][H+]
D)
rate = k[H2O2][H+]
E)
rate = k[H2O2][I–]
20. The average value for the rate constant k (without units) is
A)
2710
B)
2.74 104
C)
137
D)
108
E)
none of these
21. Two mechanisms are proposed:
I.
II.
Which mechanism and which step as the rate determining step would best fit the data?
A)
Mechanism I, with the first step the rate determining step.
B)
Mechanism I, with the second step the rate determining step.
C)
Mechanism II, with the first step rate determining.
D)
Mechanism II, with the second step rate determining.
E)
None of the above could be correct.
The following initial rate data were found for the reaction
2MnO4– + 5H2C2O4 + 6H+ → 2Mn2+ + 10CO2 + 8H2O
[MnO4–]0
[H2C2O4]0
[H+]0
Initial Rate (M/s)
1 10–3
1 10–3
1.0
2 10–4
2 10–3
1 10–3
1.0
8 10–4
2 10–3
2 10–3
1.0
1.6 10–3
2 10–3
2 10–3
2.0
1.6 10–3
22. Which of the following is the correct rate law?
A)
Rate = k[MnO4–]2[H2C2O4]5[H+]6
B)
Rate = k[MnO4–]2[H2C2O4][H+]
C)
Rate = k[MnO4–][H2C2O4][H+]
D)
Rate = k[MnO4–]2[H2C2O4]
E)
Rate = k[MnO4–]2[H2C2O4]2
23. What is the value of the rate constant?
A)
2 105 Ms–1
B)
2 105 M–2s–1
C)
200 M–1s–1
D)
200 M–2s–1
E)
2 10–4 Ms–1
The following questions refer to the reaction between nitric oxide and hydrogen
2NO + H2 → N2O + H2O
Experiment
Initial [NO], M
Initial [H2], M
Initial Rate of
Disappearance of NO
(mol/L sec)
1
6.4 10–3
2.2 10–3
2.7 10–5
2
12.8 10–3
2.2 10–3
1.1 10–4
3
6.4 10–3
4.5 10–3
5.4 10–5
24. What is the rate law for this reaction?
A)
Rate = k[NO]
B)
Rate = k[NO]2
C)
Rate = k[NO]2[H2]
D)
Rate = k[NO][H2]
E)
Rate = k[N2O][H2O]
25. What is the magnitude of the rate constant for this reaction?
A)
0.66
B)
4.2 10–3
C)
870
D)
1.9
E)
300
26. What are the units for the rate constant for this reaction?
A)
L/mol·s
B)
L2/mol2·s
C)
mol/L·s
D)
s–2
E)
L–2
27. What is the order of this reaction?
A)
3
B)
2
C)
1
D)
0
E)
cannot be determined from the data
The reaction H2SeO3(aq) 6I–(aq) + 4H+(aq) → 2I3–(aq) + 3H2O(l) + Se(s) was studied at
0°C by the method of initial rates:
[H2SeO3]0
[H+]0
[I–]0
Rate (mol/L s)
1.0 10–4
2.0 10–2
2.0 10–2
1.66 10–7
2.0 10–4
2.0 10–2
2.0 10–2
3.33 10–7
3.0 10–4
2.0 10–2
2.0 10–2
4.99 10–7
1.0 10–4
4.0 10–2
2.0 10–2
6.66 10–7
1.0 10–4
1.0 10–2
2.0 10–2
0.41 10–7
1.0 10–4
2.0 10–2
4.0 10–2
13.4 10–7
1.0 10–4
4.0 10–2
4.0 10–2
5.33 10–6
28. The rate law is
A)
Rate = k[H2SeO3][H+][I–]
B)
Rate = k[H2SeO3][H+]2[I–]
C)
Rate = k[H2SeO3][H+][I–]2
D)
Rate = k[H2SeO3]2[H+][I–]
E)
Rate = k[H2SeO3][H+]2[I–]3
29. The numerical value of the rate constant is
A)
5.2 105
B)
2.1 102
C)
4.2
D)
1.9 10–6
E)
none of these
The following questions refer to the reaction shown below:
Initial Rate of
Initial [A]
Initial [B]
Disappearance of A
Experiment
(mol/L)
(mol/L)
(mol/L·s)
1
0.16
0.15
0.08
2
0.16
0.30
0.30
3
0.08
0.30
0.08
30. What is the rate law for this reaction?
A)
Rate = k[A][B]
B)
Rate = k[A]2[B]
C)
Rate = k[A][B]2
D)
Rate = k[A]2[B]2
E)
Rate = k[B]
31. What is the magnitude of the rate constant for the reaction?
A)
140
B)
79
C)
119
D)
164
E)
21
32. What are the units for the rate constant for this reaction?
A)
L/mol·s
B)
L2/mol2·s
C)
mol/L·s
D)
L3/mol3·s
E)
mol3/L
33. What is the order of this reaction?
A)
4
B)
3
C)
2
D)
1
E)
0
34. Initial rate data have been determined at a certain temperature for the gaseous reaction
2NO + 2H2 → N2 + 2H2O
[NO]0
[H2]0
Initial Rate (M/s)
0.10
0.20
0.0150
0.10
0.30
0.0225
0.20
0.20
0.0600
What is the value of the rate constant?
A)
7.5
B)
3.0 10–3
C)
380
D)
0.75
E)
3.0 10–4
35. The following data were obtained at 25°C:
[A]0
[B]0
[C]0
Rate
0.1
0.2
0.3
0.063
0.3
0.4
0.2
0.084
0.6
0.4
0.2
0.168
0.3
0.4
0.1
0.021
0.6
0.2
0.2
0.168
What is the correct rate law?
A)
Rate = k[A][B][C]
B)
Rate = k[A][B][C]2
C)
Rate = k[A][C]
D)
Rate = k[A]3[B]2[C]
E)
Rate = k[A][C]2
The oxidation of Cr3+ to CrO42– can be accomplished using Ce4+ in a buffered solution. The
following data were obtained:
Relative
Initial Rate
[Ce4+]0
[Ce3+]0
[Cr3+]0
1
2.0 10–3
1.0 10–2
3.0 10–2
2
4.0 10–3
2.0 10–2
3.0 10–2
4
4.0 10–3
1.0 10–2
3.0 10–2
16
8.0 10–3
2.0 10–2
6.0 10–2
36. Determine the order in the rate law of the species Ce4+.
A)
1
B)
2
C)
3
D)
–1
E)
–2
37. Determine the order in the rate law of the species Ce3+.
A)
1
B)
2
C)
3
D)
–1
E)
–2
38. Determine the order in the rate law of the species Cr3+.
A)
1
B)
2
C)
3
D)
–1
E)
–2
39. The rate expression for a particular reaction is rate = k[A][B]2. If the initial concentration of
B is increased from 0.1 M to 0.3 M, the initial rate will increase by which of the following
factors?
A)
2
B)
6
C)
12
D)
3
E)
9
40. The following data were obtained for the reaction 2A + B → C where rate = [C]/t
[A](M)
[B](M)
Initial Rate
(M/s)
0.100
0.0500
2.13 10–4
0.200
0.0500
1.70 10–2
0.400
0.100
1.36 10–1
What is the value of the rate constant?
A)
2.13
B)
0.213
C)
0.426
D)
1.70
E)
none of these
41. The reaction 2A + 5B → products is second order in A and first order in B. What is the rate
law for this reaction?
A)
rate = k[A]2[B]5
B)
rate = k[A]1[B]2
C)
rate = k[A]2[B]1
D)
rate = k[A]5[B]2
E)
rate = k[A]2/7[B]5/7
42. The reaction 3A + 4B → products is second order in A and second order in B. What is the
overall order of the reaction?
A)
0
B)
7
C)
2
D)
4
E)
6
43. The reactants A and B are mixed, and the reaction is timed until a color change occurs. The
data are as follows:
[A]
[B]
Time (s)
0.100
0.140
25
0.050
0.140
50
0.100
0.070
100
The order of the reaction in terms of B is
A)
2.
B)
.
C)
0.
D)
.
E)
1.
44. The reaction has the following rate law:
After a period of s, the concentration of NO falls from an initial value of 2.8 10–
3 mol/L to 2.0 10–3 mol/L. What is the rate constant, k?
A)
B)
C)
D)
E)
45. The following data were collected for the decay of HO2 radicals:
Time
[HO2]
Time
[HO2]
0 s
1.0 1011 molec/cm3
14 s
1.25 1010 molec/cm3
2 s
5.0 1010 molec/cm3
30 s
6.225 109 molec/cm3
6 s
2.5 1010 molec/cm3
Which of the following best describes the reaction?
A)
The decay of HO2 occurs by a first-order process.
B)
The half-life of the reaction is 2 ms.
C)
A plot of ln [HO2] versus time is linear with a slope of –k.
D)
The rate of the reaction increases with time.
E)
A plot of 1/[HO2] versus time gives a straight line.
1
2
−1
2
2.7 103
1.5 10−7
5.3 10−2
3.2 10−1
1.2 10−4
2.6 10−2
46. A first-order reaction is 45% complete at the end of 43 minutes. What is the length of the
half-life of this reaction?
A)
50. min
B)
37 min
C)
2.7 h
D)
62 min
E)
none of these
The following questions refer to the gas-phase decomposition of ethylene chloride.
C2H5Cl → products
Experiment shows that the decomposition is first order.
The following data show kinetics information for this reaction:
Time (s)
ln [C2H5Cl] (M)
1.0
–1.625
2.0
–1.735
47. What is the rate constant for this decomposition?
A)
0.29/s
B)
0.35/s
C)
0.11/s
D)
0.02/s
E)
0.22/s
48. What was the initial concentration of the ethylene chloride?
A)
0.29 M
B)
0.35 M
C)
0.11 M
D)
0.02 M
E)
0.22 M
49. What would the concentration be after 5.0 seconds?
A)
0.13 M
B)
0.08 M
C)
0.02 M
D)
0.19 M
E)
0.12 M
50. What is the half-life time for this reaction?
A)
0.7 s
B)
1.3 s
C)
8.9 s
D)
6.3 s
E)
2.2 s
51. For a reaction: , [A]0 = 4.2 M, and the first two half-lives are 56 and 28
minutes, respectively. Calculate k (without units).
A)
B)
C)
D)
E)
none of these
52. For a reaction: , [A]0 = 6.0 M, and the first two half-lives are 56 and 28
minutes, respectively. Calculate [A] at t = 105.9 minutes.
A)
5.7 M
B)
12 M
C)
0.68 M
D)
0.33 M
E)
none of these
53. For which order reaction is the half-life of the reaction proportional to 1/k (k is the rate
constant)?
A)
zero order
B)
first order
C)
second order
D)
all of the above
E)
none of the above
7.5 10−2
4.3 10−3
3.7 10−2
8.5 10−3
The kinetics of the reaction were studied and the following results
obtained, where the rate law is:
For a run where [A]0 = 1.0 10–3 M and [B]0 = 5.0 M, a plot of ln [A] versus t was found to
give a straight line with slope = –5.0 10–2 s–1.
For a run where [A]0 = 1.0 10–3 M and [B]0 = 10.0 M, a plot of ln [A] versus t was found
to give a straight line with slope = –7.1 10–2 s–1.
54. What is the value of n?
A)
0
B)
0.5
C)
1
D)
1.5
E)
2
55. What is the value of m?
A)
0
B)
0.5
C)
1
D)
1.5
E)
2
56. Calculate the value of k (ignore units).
A)
22
B)
10
C)
50
D)
1.1
E)
none of these
For the reaction , the following data were collected:
t (minutes)
[N2O5] (mol/L)
0
1.24 10–2
10.
0.92 10–2
20.
0.68 10–2
30.
0.50 10–2
40.
0.37 10–2
50.
0.28 10–2
70.
0.15 10–2
57. The order of this reaction in N2O5 is
A)
0
B)
1
C)
2
D)
3
E)
none of these
58. The concentration of O2 at t = 10. minutes is
A)
2.0 10–4 mol/L
B)
0.32 10–2 mol/L
C)
0.16 10–2 mol/L
D)
0.64 10–2 mol/L
E)
none of these
59. The initial rate of production of NO2 for this reaction is approximately
A)
7.4 10–4 mol/L·min
B)
3.2 10–4 mol/L·min
C)
1.24 10–2 mol/L·min
D)
1.6 10–4 mol/L·min
E)
none of these
60. The half-life of this reaction is approximately
A)
15 minutes
B)
18 minutes
C)
23 minutes
D)
36 minutes
E)
45 minutes
61. The concentration N2O5 at 100 minutes will be approximately
A)
0.03 10–2 mol/L
B)
0.06 10–2 mol/L
C)
0.10 10–2 mol/L
D)
0.01 10–2 mol/L
E)
none of these
The following questions refer to the hypothetical reaction A + B → products. The kinetics
data given can be analyzed to answer the questions.
[A]0
[B]0
Rate of decrease
(mol/L)
(mol/L)
of [A] (M/s)
5.0
5.0
X
10.0
5.0
2X
5.0
10.0
2X
Time (s)
[B] (mol/L)
10.0
100
20.0
100
30.0
100
62. The rate law for the reaction is Rate = k[A]x[B]y. What are the values of x and y?
A)
x = 0 y = 1
B)
x = 1 y = 0
C)
x = 1 y = 1
D)
x = 2 y = 1
E)
x = 1 y = 2
63. What form will the pseudo-rate law have?
A)
Rate = k‘[A]x
B)
Rate = k‘[B]y
C)
Rate = k‘[A]x[B]y
D)
Rate = kk‘[A]x
E)
Rate = kk‘[B]y
64. Determine the magnitude of the pseudo-rate constant (k‘) if the magnitude of X in the rate
data is 0.00905.
A)
4.3 10–3
B)
1.2 10–2
C)
0.86
D)
0.31
E)
1.81 10–3
The reaction A → B + C is known to be zero order in A with a rate constant of 5.0 10–2
mol/L·s at 25°C. An experiment was run at 25°C where [A]0 = 1.0 10–3 M.
65. The integrated rate law is
A)
[A] = kt
B)
[A] – [A]0 = kt
C)
D)
E)
[A]0 – [A] = kt
66. What is the concentration of B after 5 10–3 sec?
A)
5.0 10–5 M
B)
5.0 10–4 M
C)
7.5 10–4 M
D)
2.5 10–4 M
E)
none of these
67. The reaction is known to be zero order in A with a rate constant of 5.0 10–2
mol/L s at 25°C. An experiment was run at 25°C where [A]0 = 2.0 10–3 M. After 5.0
minutes, the rate is
A)
5.0 10–2 mol/L·s
B)
2.5 10–2 mol/L·s
C)
1.3 10–2 mol/L·s
D)
2.0 10–3 mol/L·s
E)
none of these