Ch16 Kinetics Rates And Mechanisms Of Verified Test Bank

Chapter 16 Test Bank

Kinetics: Rates and Mechanisms of Chemical Reactions

1. The compound RX3 decomposes according to the equation

3RX₃ → R + R₂X₃ + 3X₂

In an experiment the following data were collected for the decomposition at 100°C. What is the average rate at which RX₃ is disappearing over the entire experiment?

t(s) [RX₃](mol L^–1)

0 0.85

2 0.67

6 0.41

8 0.33

12 0.20

14 0.16

A. 0.011 mol L^–1s^–1

B. 0.019 mol L^–1s^–1

C. 0.044 mol L^–1s^–1

D. 0.049 mol L^–1s^–1

E. 0.069 mol L^–1s^–1

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Easy

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

2. Consider the following reaction

8A(g) + 5B(g) → 8C(g) + 6D(g)

If [C] is increasing at the rate of 4.0 mol L^–1s^–1, at what rate is [B] changing?

A. –0.40 mol L^–1s^–1

B. –2.5 mol L^–1s^–1

C. –4.0 mol L^–1s^–1

D. –6.4 mol L^–1s^–1

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

3. Consider the general reaction

5Br^–(aq) + BrO₃^–(aq) + 6H⁺(aq) → 3Br₂(aq) + 3H₂O(aq)

For this reaction, the rate when expressed as Δ[Br₂]/Δt is the same as

A. –Δ[H₂O]/Δt

B. 3Δ[BrO₃^–]/Δt

C. –5Δ[Br^–]/Δt

D. –0.6Δ[Br^–]/Δt

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

4. Consider the reaction

2NH₃(g) → N₂(g) + 3H₂(g)

If the rate Δ[H₂]/Δt is 0.030 mol L_–1s_–1, then Δ[NH₃ ]/Δt is

A. –0.045 mol L^–1 s^–1

B. –0.030 mol L^–1 s^–1

C. –0.020 mol L^–1 s^–1

D. –0.010 mol L^–1 s^–1

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

5. For the reaction

3A(g) + 2B(g) → 2C(g) + 2D(g)

the following data were collected at constant temperature. Determine the correct rate law for this reaction.

Trial Initial [A] Initial [B] Initial Rate

(mol/L) (mol/L) (mol/(L·min))

1 0.200 0.100 6.00 × 10^–2

2 0.100 0.100 1.50 × 10^–2

3 0.200 0.200 1.20 × 10^–1

4 0.300 0.200 2.70 × 10^–1

A. Rate = k[A][B]

B. Rate = k[A][B]²

C. Rate = k[A]³[B] ²

D. Rate = k[A]^1.5[B]

E. Rate = k[A] ²[B]

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

6. For the reaction

A(g) + 2B(g) → 2C(g) + 2D(g)

the following data were collected at constant temperature. Determine the correct rate law for this reaction.

Trial Initial [A] Initial [B] Initial Rate

(mol/L) (mol/L) (mol/(L·min))

1 0.125 0.200 7.25

2 0.375 0.200 21.75

3 0.250 0.400 14.50

4 0.375 0.400 21.75

A. Rate = k[A] [B]

B. Rate = k[A]² [B]

C. Rate = k[A] [B]²

D. Rate = k[A]

E. Rate = k[A]³

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

7. For the reaction

2A + B + 2C → D + E

the following initial rate data were collected at constant temperature. Determine the correct rate law for this reaction. All units are arbitrary.

Trial [A] [B] [C] Rate

1 0.225 0.150 0.350 0.0217

2 0.320 0.150 0.350 0.0439

3 0.225 0.250 0.350 0.0362

4 0.225 0.150 0.600 0.01270

A. Rate = k[A][B][C]

B. Rate = k[A]²[B][C]

C. Rate = k[A]²[B][C]^–1

D. Rate = k[A][B]²[C] ^–1

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

8. For the reaction

A(g) + 2B(g) → 2C(g) + 2D(g)

the following data were collected at constant temperature. Determine the correct rate law for this reaction.

Trial Initial [A] Initial [B] Initial Rate

(mol/L) (mol/L) (mol/(L·min))

1 0.125 0.200 7.25

2 0.375 0.200 21.75

3 0.250 0.400 14.50

4 0.375 0.400 21.75

A. Rate = k[A] [B]

B. Rate = k[A]² [B]

C. Rate = k[A] [B]²

D. Rate = k[A]

E. Rate = k[A]³

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

9. Sulfuryl chloride, SO₂Cl₂(g), decomposes at high temperature to form SO₂(g) and Cl₂(g). The rate constant at a certain temperature is 4.68 × 10^–5s^–1. What is the order of the reaction?

A. Zero

B. First

C. Second

D. Third

E. More information is needed to determine the order.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Easy

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

10. When the reaction A → B + C is studied, a plot of ln[A]_t vs. time gives a straight line with a negative slope. What is the order of the reaction?

A. Zero

B. First

C. Second

D. Third

E. More information is needed to determine the order.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Easy

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

11. When the reaction A → B + C is studied, a plot 1/[A]_t vs. time gives a straight line with a positive slope. What is the order of the reaction?

A. Zero

B. First

C. Second

D. Third

E. More information is needed to determine the order.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Easy

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

12. Which of the following sets of units could be appropriate for a zero-order rate constant?

A. s^–1

B. L mol^–1s^–1

C. L² mol^–2s^–1

D. L³ mol^–3s^–1

E. mol L^–1s^–1

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

13. Which one of the following sets of units is appropriate for a second-order rate constant?

A. s^–1

B. mol L^–1s^–1

C. L mol^–1s^–1

D. mol² L^–2s^–1

E. L² mol^–2s^–1

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

14. Which one of the following sets of units is appropriate for a third-order rate constant?

A. s^–1

B. mol L^–1s^–1

C. L mol^–1s^–1

D. L² mol^–2s^–1

E. L³ mol^–3s^–1

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

15. A reaction has the following rate law:

Rate = k[A][B]₂

In experiment 1, the concentrations of A and B are both 0.10 mol L^–1; in experiment 2, the concentrations are both 0.30 mol L^–1. If the temperature stays constant, what is the value of the ratio, Rate(2)/Rate(1)?

A. 3.0

B. 6.0

C. 9.0

D. 18

E. 27

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

16. Ammonium cyanate (NH₄CNO) reacts to form urea (NH₂CONH₂). At 65°C the rate constant, k, is 3.60 L mol^–1s^–1.What is the rate law for this reaction?

A. Rate = 3.60 L mol^–1s^–1[NH₄CNO]

B. Rate = 3.60 L mol^–1s^–1 [NH₄CNO]²

C. Rate = 0.28 mol L^–1s^–1 [NH₄CNO]

D. Rate = 0.28 mol L^–1s^–1[NH₄CNO]²

E. Rate = 3.60 L mol^–1s^–1 [NH₂CONH₂]^–1

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

17. 2NOBr(g) → 2NO(g) + Br₂(g)

[NOBr](mol L^–1) Rate (molL^–1s^–1)

0.0450 1.62 × 10^–3

0.0310 7.69 × 10^–4

0.0095 7.22 × 10^–5

Based on the initial rate data above, what is the value of the rate constant?

A. 0.0360 L mol^–1s^–1

B. 0.800 L mol^–1s^–1

C. 1.25 L mol^–1s^–1

D. 27.8 L mol^–1s^–1

E. 0.0360 s^–1

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

18. A study of the decomposition reaction 3RS₂ → 3R + 6S yields the following initial rate data.

[RS₂](mol L^–1) Rate (mol/(L·s))

0.150 0.0394

0.250 0.109

0.350 0.214

0.500 0.438

What is the rate constant for the reaction?

A. 0.0103 L mol^–1s^–1

B. 0.263 L mol^–1s^–1

C. 0.571 L mol^–1s^–1

D. 1.17 L mol^–1s^–1

E. 1.75 L mol^–1s^–1

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

19. Sulfur trioxide can undergo decomposition according to the equation

2SO₃ → 2SO₂ + O₂

For this reaction, rate = –0.5Δ[SO₃ ]/Δt = k[SO₃]². If the reaction rate is 1.75 × 10^–7 mol L^–1 min^–1 when the concentration of sulfur trioxide is 5.4 × 10^–3 mol L^–1, what is the value of the rate constant k?

A. 3.2 × 10^–5 L mol^–1 min^–1

B. 1.6 × 10^–5 L mol^–1 min^–1

C. 6.0 × 10^–3 L mol^–1 min^–1

D. 3.0 × 10^–3 L mol^–1 min^–1

E. 1.6 × 10^–2 L mol^–1 min^–1

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

20. Sucrose decomposes to fructose and glucose in acid solution. When ln [sucrose] is plotted vs. time, a straight line with slope of –0.208 hr^–1 results. What is the rate law for the reaction?

A. Rate = 0.208 hr^–1 [sucrose]²

B. Rate = 0.208 hr^–1 [sucrose]

C. Rate = 0.0433 hr [sucrose]²

D. Rate = 0.0433 hr [sucrose]

E. Rate = 0.208 mol L^–1hr^–1 [sucrose]⁰

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

21. Tetrafluoroethylene, C₂F₄, can be converted to octafluorocyclobutane which can be used as a refrigerant or an aerosol propellant. A plot of 1/[C₂F₄] vs. time gives a straight line with a slope of 0.0448 L mol^–1s^–1. What is the rate law for this reaction?

A. Rate = 0.0448 (L mol^–1s^–1)[C₂F₄]

B. Rate = 22.3 (mol L^–1s)[C₂F₄]

C. Rate = 0.0448 (L mol^–1s^–1)[C₂F₄]²

D. Rate = 22.3 (mol L^–1s)[C₂F₄]²

E. Rate = 0.0448 s^–1 [C₂F₄]

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

22. A reaction is first-order with respect to the reactant R. Which of the following plots will produce a straight line?

A. [R] vs. 1/time

B. 1/[R] vs. time

C. [R]² vs. time

D. 1/[R]² vs. time

E. ln[R] vs. time

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

23. A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

A. [R] vs. 1/time

B. 1/[R] vs. time

C. [R]² vs. time

D. 1/[R]² vs. time

E. ln[R] vs. time

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

24. The reaction X → Y is first-order overall and first-order with respect to the reactant X. The result of doubling the initial concentration of X will be to

A. shorten the half-life of the reaction.

B. increase the rate constant of the reaction.

C. decrease the rate constant of the reaction.

D. shorten the time taken to reach equilibrium.

E. double the initial rate.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

25. The decomposition of hydrogen peroxide is a first-order process with a rate constant of 1.06 × 10^–3 min^–1. How long will it take for the concentration of H₂O₂ to drop from 0.0200 M to 0.0120 M?

A. < 1 min

B. 7.55 min

C. 481 min

D. 4550 min

E. 31,400 min

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

26. Cyclopropane is converted to propene in a first-order process. The rate constant is 5.4 × 10^–2 hr^–1. If the initial concentration of cyclopropane is 0.150 M, what will its concentration be after 22.0 hours?

A. 0.0457 M

B. 0.105 M

C. 0.127 M

D. 0.492 M

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

27. A gas-phase decomposition is first–order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10^–4 mol L^–1 and the rate constant k = 1.08 × 10^–6 s^–1, what concentration of R remains after 25 days?

A. 1.0 × 10^–3 mol L^–1

B. 1.0 × 10^–4 mol L^–1

C. 9.6 × 10^–5 mol L^–1

D. 4.3 × 10^–5 mol L^–1

E. 9.7 × 10^–6 mol L^–1

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

28. The rate law for the reaction 3A → 2B is rate = k[A] with a rate constant of 0.0447 hr^–1. What is the half-life of the reaction?

A. 0.0224 hr

B. 0.0645 hr

C. 15.5 hr

D. 22.4 hr

E. 44.7 hr

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

29. The rate law for the rearrangement of CH₃NC to CH₃CN at 800 K is Rate = (1300 s^–1)[CH₃NC]. What is the half-life for this reaction?

A. 7.69 × 10^–4 s

B. 5.3 × 10^–4 s

C. 1.9 × 10^–3 s

D. 520 s

E. 1920 s

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

30. The rate constant for the reaction 3A → 4B is 6.00 × 10^–3 L mol^–1min^–1. How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

A. 2.2 × 10^–3 min

B. 5.5 × 10^–3 min

C. 180 min

D. 440 min

E. 5.0 × 10² min

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

31. The active ingredient in an over the counter pain killer analgesic decomposes with a rate constant, k = 9.05 × 10^–4 day^–1.

How many days does it take for 15% of the original ingredient to decompose?

A. 730 days

B. 414 days

C. 365 days

D. 180 days

E. 78 days

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

32. Butadiene, C₄H₆ (used to make synthetic rubber and latex paints) reacts to C₈H₁₂ with a rate law of rate = 0.014 L/(mol·s) [C₄H₆]². What will be the concentration of C₄H₆ after 3.0 hours if the initial concentration is 0.025 M?

A. 0.0052 M

B. 0.024 M

C. 43 M

D. 190 M

E. 0.0000 M

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

33. The rate law for the reaction 3A → C is

Rate = 4.36 × 10^–2 L mol^–1 hr^–1 [A]²

What is the half-life for the reaction if the initial concentration of A is 0.250 M?

A. 0.0109 hr

B. 0.0629 hr

C. 15.9 hr

D. 23.9 hr

E. 91.7 hr

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

34. The decomposition of SOCl₂ is first-order in SOCl₂. If the half-life for the reaction is 4.1 hr, how long would it take for the concentration of SOCl₂ to drop from 0.36 M to 0.045 M?

A. 0.52 hr

B. 1.4 hr

C. 12 hr

D. 33 hr

E. > 40 hr

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

35. The reaction CH₃NC(g) → CH₃CN(g) is first-order with respect to methyl isocyanide, CH₃NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min^–1 ?

A. –0.135 min^–1

B. 0.0279 min^–1

C. 0.089 min^–1

D. 0.135 min^–1

E. 35.8 min^–1

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

36. A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

A. 0.94

B. 0.87

C. 0.75

D. 0.13

E. 0.063

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

37. A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 × 10²⁰ molecules of reactant at time t = 0, how many molecules remain unreacted after 100.0 minutes?

A. 1.00 × 10⁴ molecules

B. 2.00 × 10¹⁹ molecules

C. 3.20 × 10¹⁶ molecules

D. 5.00 × 10²⁰ molecules

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

38. Carbon-14 is a radioactive isotope which decays with a half-life of 5730 years. What is the first-order rate constant for its decay, in units of years–1?

A. 5.25 × 10^–5 years^–1

B. 1.21 × 10^–4 years^–1

C. 1.75 × 10^–4 years^–1

D. 3.49 × 10^–4 years^–1

E. 3.97 × 10³ years^–1

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

39. The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year^–1. What fraction of the tritium initially in a sample is still present 30 years later?

A. 0.19

B. 0.60

C. 0.15

D. 2.8 × 10^–38

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order)

Topic: Chemical Kinetics (Reaction Rates)

40. Dinitrogen tetraoxide, N₂O₄, decomposes to nitrogen dioxide, NO₂, in a first-order process. If k = 2.5 × 10³ s^–1 at –5°C and k = 3.5 × 10⁴ s^–1 at 25°C, what is the activation energy for the decomposition?

A. 0.73 kJ/mol

B. 58 kJ/mol

C. 140 kJ/mol

D. 580 kJ/mol

E. > 1000 kJ/mol

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

41. Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?

A. 24.5 kJ/mol

B. 165 kJ/mol

C. 242 kJ/mol

D. 1630 kJ/mol

E. > 10⁴ kJ/mol

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

42. In going from room temperature (25.0°C) to 10°C above room temperature, the rate of a reaction doubles. Calculate the activation energy for the reaction.

A. 157.2 kJ/mol

B. 103.8 kJ/mol

C. 52.9 kJ/mol

D. 6.4 kJ/mol

E. <1 kJ/mol

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

43. A boiled egg can be cooked at 100.0°C in exactly 5 minutes. At an altitude of around 2000 m where the boiling point of water is 93.0°C, it takes exactly 7.5 minutes to cook the egg to the same amount. What is the activation energy for the reaction involved when an egg is boiled?

A. 0.5 kJ/mol

B. 4.5 kJ/mol

C. 7.9 kJ/mol

D. 66 kJ/mol

E. >100 kJ/mol

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

44. If the activation energy of a reaction decreases by 10.0 kJ/mol, from 100.0 to 90.0 kJ/mol, what effect will this have on the rate of reaction at 298K?

A. The rate will increase, by a factor of more than 50.

B. The rate will decrease, by a factor of more than 50.

C. The rate will increase, by a factor of less than 50.

D. The rate will decrease, by a factor of less than 50.

E. The rate will not change unless temperature changes.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

45. A rate constant obeys the Arrhenius equation, the factor A being 2.2 ×10¹³ s^–1 and the activation energy being 150. kJ mol^–1. What is the value of the rate constant at 227°C, in s^–1?

A. 2.1 × 10¹³ s^–1

B. 6.7 × 10^–22 s^–1

C. 1.5 × 10¹¹ s^–1

D. 4.7 × 10^–3 s^–1

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

46. A reaction has an activation energy of 195.0 kJ/mol. When the temperature is increased from 200°C to 220°C, the rate constant will increase by a factor of

A. 1.1.

B. 4.3 × 10⁴.

C. 3.2.

D. 7.5.

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

47. The decomposition of dinitrogen pentaoxide to nitrogen dioxide and oxygen follows first-order kinetics and has an activation energy of 102 kJ/mol. By what factor will the fraction of collisions with energy greater than or equal to the activation energy increase if the reaction temperature goes from 30°C to 60°C?

A. 1.00

B. 1.10

C. 2.00

D. 4.00

E. 38.4

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

48. The decomposition of dinitrogen pentaoxide has an activation energy of 102 kJ/mol and ΔH°_rxn = + 55 kJ/mol. What is the activation energy for the reverse reaction?

A. 27 kJ/mol

B. 47 kJ/mol

C. 55 kJ/mol

D. 102 kJ/mol

E. More information is needed, since this is a Hess's law calculation.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

49. The kinetics of the decomposition of dinitrogen pentaoxide is studied at 50°C and at 75°C. Which of the following statements concerning the studies is correct?

A. The rate at 75°C will be greater than the rate at 50°C because the activation energy will be lower at 75°C than at 50°C.

B. The rate at 75°C will be greater than the rate at 50°C because the activation energy will be higher at 75°C than at 50°C.

C. The rate at 75°C will be less than the rate at 50°C because the molecules at higher speeds do not interact as well as those at lower speeds.

D. The rate at 75°C will be greater than at 50°C because the concentration of a gas increases with increasing temperature.

E. The rate at 75°C will be greater than the rate at 50°C because the number of molecules with enough energy to react increases with increasing temperature.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

50. An increase in temperature increases the reaction rate because

A. a greater fraction of the collisions have the correct orientation of molecules.

B. the activation energy of the reaction will increase.

C. the activation energy of the reaction will decrease.

D. temperature acts as a catalyst in chemical reactions.

E. more collisions will have enough energy to exceed the activation energy.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Easy

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

51. In an exothermic reaction,

A. the forward reaction is slower than the reverse reaction.

B. the reaction rate will speed up with time.

C. the collision energy of the reactants will be greater than that of the products.

D. the forward reaction will have a lower activation energy than the reverse reaction.

E. the activation energy will change as the reaction progresses.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

52. Reaction intermediates differ from activated complexes in that

A. they are stable molecules with normal bonds and are frequently isolated.

B. they are molecules with normal bonds rather than partial bonds and can occasionally be isolated.

C. they are intermediate structures which have characteristics of both reactants and products.

D. they are unstable and can never be isolated.

E. all reactions involve reaction intermediates, but not all have activated complexes.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

53. Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution.

H⁺ + H₂O₂ H₂O⁺–OH (rapid equilibrium)

H₂O⁺–OH + Br^– → HOBr + H₂O (slow)

HOBr + H⁺ + Br^– → Br₂ + H₂O (fast)

What is the overall reaction equation for this process?

A. 2H₂O⁺–OH + 2Br^– → H₂O₂ + Br₂ + 2H₂O

B. 2H⁺ + 2Br^– + H₂O₂ → Br₂ + 2H₂O

C. 2H⁺ + H₂O₂ + Br^– + HOBr → H₂O⁺–OH + Br₂ + H₂O

D. H₂O⁺–OH + Br^– + H⁺ → Br₂ + H₂O

E. None of these choices are correct.

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

54. What is the molecularity of the following elementary reaction?

NH₂Cl(aq) + OH_– (aq) → NHCl_– (aq) + H₂O(l)

A. Unimolecular

B. Bimolecular

C. Termolecular

D. Tetramolecular

E. Need to know the reaction order before molecularity can be determined.

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Easy

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

55. Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution.

H⁺ + H₂O₂ H₂O⁺–OH (rapid equilibrium)

H₂O⁺–OH + Br^– → HOBr + H₂O (slow)

HOBr + H⁺ + Br^– → Br₂ + H₂O (fast)

Which of the following rate laws is consistent with the mechanism?

A. Rate = k[H₂O₂][H⁺]²[Br^–]

B. Rate = k[H₂O+–OH][Br^–]

C. Rate = k[H₂O₂][H⁺][Br^–]

D. Rate = k[HOBr][H⁺][Br^–][H₂O₂]

E. Rate = k[Br^–]

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

56. Which of the following affects the activation energy of a reaction?

A. temperature of the reactants

B. concentrations of reactants

C. presence of a catalyst

D. surface area of reactants

E. reaction progress

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Easy

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

57. A catalyst accelerates a reaction because

A. it increases the number of molecules with energy equal to or greater than the activation energy.

B. it lowers the activation energy for the reaction.

C. it increases the number of collisions between molecules.

D. it increases the temperature of the molecules in the reaction.

E. it supplies energy to reactant molecules.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Catalysis

Topic: Chemical Kinetics (Reaction Rates)

58. When a catalyst is added to a reaction mixture, it

A. increases the rate of collisions between reactant molecules.

B. provides reactant molecules with more energy.

C. slows down the rate of the back reaction.

D. provides a new pathway (mechanism) for the reaction.

E. None of these choices are correct.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Catalysis

Topic: Chemical Kinetics (Reaction Rates)

59. The gas-phase reaction CH₃NC → CH₃CN has been studied in a closed vessel, and the rate equation was found to be: Rate = –Δ[CH₃NC]/Δt = k[CH₃NC]. Which one of the following actions is least likely to cause a change in the rate of the reaction?

A. lowering the temperature

B. adding a catalyst

C. using a larger initial amount of CH₃NC in the same vessel

D. using a bigger vessel, but the same initial amount of CH₃NC

E. continuously removing CH₃CN as it is formed

Accessibility: Keyboard Navigation

Bloom's: 2. Understand

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

60. The rate law cannot be predicted from the stoichiometry of a reaction.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

61. The units of the rate constant depend on the order of the reaction.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

62. The units of the rate of reaction depend on the order of the reaction.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

63. The half-life of a first-order reaction does not depend on the initial concentration of reactant.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

64. The half-life of a second-order reaction does not depend on the initial concentration of reactant.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Half-Life

Topic: Chemical Kinetics (Reaction Rates)

65. The greater the energy of activation, Ea, the faster will be the reaction.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

66. An elementary reaction is a simple, one-step process.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

67. All second-order reactions are bimolecular reactions.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Hard

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

68. All bimolecular reactions are second-order reactions.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

69. The rate of a reaction is determined by the rate of the fastest step in the mechanism.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

70. A transition state is a species (or state) corresponding to an energy maximum on a reaction energy diagram.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

71. A reaction intermediate is a species corresponding to a local energy maximum on a reaction energy diagram.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Medium

Gradable: automatic

Subtopic: Reaction Rate and Collision Theory

Topic: Chemical Kinetics (Reaction Rates)

72. A catalyst lowers the activation energy but does not affect the mechanism of a reaction.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Medium

Gradable: automatic

Subtopic: Catalysis

Subtopic: Chemical Kinetics (Reaction Rates)

73. In a reversible reaction, a catalyst will speed up the forward reaction but not affect the reverse reaction.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Medium

Gradable: automatic

Subtopic: Catalysis

Subtopic: Chemical Kinetics (Reaction Rates)

74. In the lock and key model of enzyme action, the active site on the enzyme provides an exact fit for the substrate.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Catalysis

Topic: Chemical Kinetics (Reaction Rates)

75. Chlorine atoms act as heterogeneous catalysts in the destruction of ozone in the stratosphere.

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Catalysis

Subtopic: Chemical Kinetics (Reaction Rates)

76. Consider the reaction

2A + 2B + C → 2D + E

If the rate law for this reaction is Rate = k[A][B]², what will be the effect on the rate if the concentrations of A, B and C are all doubled at the same time?

A. The rate will increase by a factor of 2.

B. The rate will increase by a factor of 4.

C. The rate will increase by a factor of 6.

D. The rate will increase by a factor of 8.

E. More information is needed before this question can be answered.

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Medium

Gradable: automatic

Subtopic: Rate Law

Topic: Chemical Kinetics (Reaction Rates)

77. The reaction of ethylene (C₂H₄) with butadiene (C₄H₆=) to form cyclohexene (C₆H₁₀) has an activation energy (E_a) of 115 kJ/mol. The reverse reaction (decomposition of cyclohexene to ethylene and butadiene) has an activation energy of 287 kJ/mol. What is the heat of reaction, Δ H_rxn, for the forward reaction?

A. +115 kJ/mol

B. +287 kJ/mol

C. -287 kJ/mol

D. +172 kJ/mol

E. -172 kJ/mol

Accessibility: Keyboard Navigation

Bloom's: 3. Apply

Difficulty: Hard

Gradable: automatic

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation)

Topic: Chemical Kinetics (Reaction Rates)

78. In order to obtain the activation energy of a reaction using a graphical method, __________ is plotted against _________, giving a straight line whose slope is equal to __________.

A. k; T; -E_a

B. k; 1/T; -E_a

C. lnk; T; -E_a/R

D. k; 1/T; -E_a/R

E. lnk; 1/T; -E_a/R

Accessibility: Keyboard Navigation

Bloom's: 1. Remember

Difficulty: Easy

Gradable: automatic

Subtopic: Reaction Mechanism

Topic: Chemical Kinetics (Reaction Rates)

Category # of Questions

Accessibility: Keyboard Navigation 76

Bloom's: 1. Remember 23

Bloom's: 2. Understand 21

Bloom's: 3. Apply 34

Difficulty: Hard 16

Difficulty: Medium 37

Difficulty: Easy 23

Difficulty: Medium 2

Gradable: automatic 78

Subtopic: Catalysis 6

Subtopic: Chemical Kinetics (Reaction Rates) 3

Subtopic: Concentration Change Over Time (Integrated Rate Law and Reaction Order) 15

Subtopic: Effect of Temperature on Reaction Rate (Arrhenius Equation) 12

Subtopic: Half-Life 8

Subtopic: Rate Law 18

Subtopic: Reaction Mechanism 9

Subtopic: Reaction Rate and Collision Theory 10

Topic: Chemical Kinetics (Reaction Rates) 75