1. University of Kentucky
Clicker Questions
Chapter 13
Chemical Kinetics
Allison Soult
University of Kentucky

2. Determine the rate of disappearance of NO in the first 100 seconds.
time (s)
0.100
0.078 50
0.059
100
0.043
150
0.031
200
3.4 × 10–4 M/s
5.9 × 10–4 M/s
4.1 × 10–4 M/s
1.6 × 10–4 M/s
2.1 × 10–4 M/s
Answer: c

3. Determine the rate of disappearance of NO in the first 100 seconds.
time (s)
0.100
0.078 50
0.059
100
0.043
150
0.031
200
3.4 × 10–4 M/s
5.9 × 10–4 M/s
4.1 × 10–4 M/s
1.6 × 10–4 M/s
2.1 × 10–4 M/s
Answer: c

4. H2O2 can be used as a disinfectant; it decomposes as:
2 H2O2  2 H2O + O2
If the rate of appearance of O2 is Ms–1, what is the rate of disappearance of H2O2?
Ms–1
Ms–1
Ms–1
None of the above are correct.
Answer: c

5. H2O2 can be used as a disinfectant; it decomposes as:
2 H2O2  2 H2O + O2
If the rate of appearance of O2 is Ms–1, what is the rate of disappearance of H2O2?
Ms–1
Ms–1
Ms–1
None of the above are correct.
Answer: c

6. What is the order of a reaction that has the following time and concentration data?
Time (s)
[Concentration] 50
100
150
200
250
Zero order
First order
Second order
None of the above
Answer: c

7. What is the order of a reaction that has the following time and concentration data?
Time (s)
[Concentration] 50
100
150
200
250
Zero order
First order
Second order
None of the above
Answer: c

8. Determine the units on the rate constant, k, for a reaction with the following rate law.
Rate = k[A]2[B]3
M–1s–1
M–2s–1
M–1s–4
M–4s–1
M–2s–3
Answer: d

9. Determine the units on the rate constant, k, for a reaction with the following rate law.
Rate = k[A]2[B]3
M–1s–1
M–2s–1
M–1s–4
M–4s–1
M–2s–3
Answer: d

10. Determine the overall order for a reaction with the following rate law.
Rate = k[A]2[B][C]3
Second order
Third order
Fourth order
Fifth order
Sixth order
Answer: e

11. Determine the overall order for a reaction with the following rate law.
Rate = k[A]2[B][C]3
Second order
Third order
Fourth order
Fifth order
Sixth order
Answer: e

12. 2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l)
What is the order of the reaction with respect to OH–?
2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l) 1 2 3 4
[ClO2]
[OH–]
Initial Rate (M/s)
0.060
0.030
0.0248
0.020
0.090
Answer: a

13. 2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l)
What is the order of the reaction with respect to OH–?
2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l) 1 2 3 4
[ClO2]
[OH–]
Initial Rate (M/s)
0.060
0.030
0.0248
0.020
0.090
Answer: a

14. 2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l)
What is the value of the rate constant, k, for the reaction?
2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l)
4.35 × 10–3 M–1s–1
13.8 M–1s–1
4.60 M–1s–1
230. M–2s–1
459 M–1s–1
[ClO2]
[OH–]
Initial Rate (M/s)
0.060
0.030
0.0248
0.020
0.090
Answer: d

15. 2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l)
What is the value of the rate constant, k, for the reaction?
2 ClO2 (aq) + 2 OH– (aq) → ClO3– (aq) + ClO2– (aq) + H2O (l)
4.35 × 10–3 M–1s–1
13.8 M–1s–1
4.60 M–1s–1
230. M–2s–1
459 M–1s–1
[ClO2]
[OH–]
Initial Rate (M/s)
0.060
0.030
0.0248
0.020
0.090
Answer: d

16. A reaction proceeds according to first order kinetics
A reaction proceeds according to first order kinetics. If the initial concentration is 1.5 M and the rate constant is s–1, what is the concentration after 24.5 seconds?
0.48 M
0.29 M
0.075 M
0.32 M
0.73 M
Answer: e

17. A reaction proceeds according to first order kinetics
A reaction proceeds according to first order kinetics. If the initial concentration is 1.5 M and the rate constant is s–1, what is the concentration after 24.5 seconds?
0.48 M
0.29 M
0.075 M
0.32 M
0.73 M
Answer: e

18. A substance decays with second order kinetics
A substance decays with second order kinetics. What is the half-life given a rate constant that is 0.37 M–1 s–1 and an initial concentration of 0.75 M?
2.0 s
3.6 s
0.28 s
0.49 s
Answer: b

19. A substance decays with second order kinetics
A substance decays with second order kinetics. What is the half-life given a rate constant that is 0.37 M–1 s–1 and an initial concentration of 0.75 M?
2.0 s
3.6 s
0.28 s
0.49 s
Answer: b

20. How many half-lives are required for uranium to decay to 12
How many half-lives are required for uranium to decay to 12.5 % of its original value? 1
1.75 2 3
None of the above
Answer: d

21. How many half-lives are required for uranium to decay to 12
How many half-lives are required for uranium to decay to 12.5 % of its original value? 1
1.75 2 3
None of the above
Answer: d

22. What reaction order has a half-life independent of its initial concentration?
Zero
First
Second
Zero and second
Zero and first
Answer: b

23. What reaction order has a half-life independent of its initial concentration?
Zero
First
Second
Zero and second
Zero and first
Answer: b

24. A zero order reaction has a rate constant of 0. 28
A zero order reaction has a rate constant of How long will it take for the reactant to reach 30% of its original concentration?
2.5 × 102 s
4.3 s
0.083 s
20 s
1.8 s
Answer: a

25. A zero order reaction has a rate constant of 0. 28
A zero order reaction has a rate constant of How long will it take for the reactant to reach 30% of its original concentration?
2.5 × 102 s
4.3 s
0.083 s
20 s
1.8 s
Answer: a

26. The chirping of tree crickets has sometimes been used to predict temperatures. At 25.0 °C the rate was 179 chirps/min. At 21.7 °C it was 142 chirps/min. What is the Ea of the process?
316 J
51,300 J
0.749 kJ
6.16 kJ
Answer: b

27. The chirping of tree crickets has sometimes been used to predict temperatures. At 25.0 ° C the rate was 179 chirps/min. At 21.7 ° C it was 142 chirps/min. What is the Ea of the process?
316 J
51,300 J
0.749 kJ
6.16 kJ
Answer: b

28. The rate determining step in a reaction is
always the first step.
always the last step.
the slow step.
the fast step.
Answer: c

29. The rate determining step in a reaction is
always the first step.
always the last step.
the slow step.
the fast step.
Answer: c

30. A possible mechanism for the overall reaction is found below: Br2 (g) + 2 NO (g) → 2 NOBr (g) Step 1 (fast) NO (g) + Br2 (g) NOBr2 (g) Step 2 (slow) NOBr2 (g) + NO (g) → 2 NOBr (g) The rate law based on this mechanism is
k1[NO]1/2
k1[Br]1/2
(k1k2/k–1)[NO]2[Br2]
(k1/k–1)2[NO]2
(k1k2/k–1)[NO][Br2]2
Answer: c

31. A possible mechanism for the overall reaction is found below: Br2 (g) + 2 NO (g) → 2 NOBr (g) Step 1 (fast) NO (g) + Br2 (g) NOBr2 (g) Step 2 (slow) NOBr2 (g) + NO (g) → 2 NOBr (g) The rate law based on this mechanism is
k1[NO]1/2
k1[Br]1/2
(k1k2/k–1)[NO]2[Br2]
(k1/k–1)2[NO]2
(k1k2/k–1)[NO][Br2]2
Answer: c

32. H2O2 + I−  H2OH + IO− H2O2 + IO−  H2O + O2
Does this reaction mechanism have an intermediate and/or catalyst?
H2O2 + I−  H2OH + IO− H2O2 + IO−  H2O + O2
Only an intermediate
Only a catalyst
An intermediate and a catalyst
Neither an intermediate nor a catalyst
Answer: c

33. H2O2 + I−  H2OH + IO− H2O2 + IO−  H2O + O2
Does this reaction mechanism have an intermediate and/or catalyst?
H2O2 + I−  H2OH + IO− H2O2 + IO−  H2O + O2
Only an intermediate
Only a catalyst
An intermediate and a catalyst
Neither an intermediate nor a catalyst
Answer: c