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

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

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

H2O2 can be used as a disinfectant; it decomposes as: 2 H2O2  2 H2O + O2 If the rate of appearance of O2 is 0.0014 Ms–1, what is the rate of disappearance of H2O2? 0.0014 Ms–1 0.00070 Ms–1 0.0028 Ms–1 None of the above are correct. Answer: c

H2O2 can be used as a disinfectant; it decomposes as: 2 H2O2  2 H2O + O2 If the rate of appearance of O2 is 0.0014 Ms–1, what is the rate of disappearance of H2O2? 0.0014 Ms–1 0.00070 Ms–1 0.0028 Ms–1 None of the above are correct. Answer: c

What is the order of a reaction that has the following time and concentration data? Time (s) [Concentration] 0.01000 50 0.00887 100 0.00797 150 0.00723 200 0.00662 250 0.00611 Zero order First order Second order None of the above Answer: c

What is the order of a reaction that has the following time and concentration data? Time (s) [Concentration] 0.01000 50 0.00887 100 0.00797 150 0.00723 200 0.00662 250 0.00611 Zero order First order Second order None of the above Answer: c

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

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

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

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

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 0.00276 0.090 0.00828 Answer: a

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 0.00276 0.090 0.00828 Answer: a

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 0.00276 0.090 0.00828 Answer: d

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 0.00276 0.090 0.00828 Answer: d

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 0.0294 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

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 0.0294 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

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

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

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

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

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

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

A zero order reaction has a rate constant of 0. 28 A zero order reaction has a rate constant of 0.28. 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

A zero order reaction has a rate constant of 0. 28 A zero order reaction has a rate constant of 0.28. 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

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

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

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

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

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

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

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

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