Test Bank Answers Chapter 9 Reaction Kinetics

Chapter 9: Reaction Kinetics

Test Bank

Type: multiple choice question

Title: Chapter 09 Question 01

1) For the following reaction H₂ (g) + I₂ (g) → 2 HI (g), the initial rate of formation of hydrogen iodide was found to be 3.2 × 10^-3 mol dm^-3 s^-1. What is the initial rate of consumption of H₂?

a. 3.2 × 10^-3 mol dm^-3 s^-1.

Section reference: 9.2

b. 1.6 × 10^-3 mol dm^-3 s^-1.

Section reference: 9.2

c. 6.4 × 10^-3 mol dm^-3 s^-1.

Section reference: 9.2

d. Not possible to determine.

Section reference: 9.2

Type: multiple choice question

Title: Chapter 09 Question 02

2) For the following reaction: 2 N₂O₅ (g) → 4 NO₂ (g) + O₂ (g) the initial rate of formation of O₂ was found to be 1.25 × 10^-4 mol dm^-3 s^-1. What is the initial rate of consumption of N₂O₅?

a. 2.50 × 10^-4 mol dm^-3 s^-1.

Section reference: 9.2

b. 1.25 × 10^-4 mol dm^-3 s^-1.

Section reference: 9.2

c. 3.75 × 10^-4 mol dm^-3 s^-1.

Section reference: 9.2

d. 5.00 × 10^-4 mol dm^-3 s^-1.

Section reference: 9.2

Type: multiple choice question

Title: Chapter 09 Question 03

3) For the following reaction: BrO₃^- (aq) + 5 Br^- (aq) + 6 H₃O⁺ (aq) → 3 Br₂ (aq) + 9 H₂O (aq), the initial rate of formation of Br₂ was found to be 2.4 × 10^-3 mol dm^-3 s^-1. What is the initial rate of formation of H₂O?

a. 2.4 × 10^-3 mol dm^-3 s^-1.

Section reference: 9.2

b. 2.16 × 10^-2 mol dm^-3 s^-1

Section reference: 9.2

c. 4.8 × 10^-3 mol dm^-3 s^-1.

Section reference: 9.2

d. 7.2 × 10^-3 mol dm^-3 s^-1.

Section reference: 9.2

Type: multiple choice question

Title: Chapter 09 Question 04

4) For the following reaction: 2 NH₃ (g) → N₂ (g) + 3 H₂ (g), the rate of consumption of ammonia was measured as 2 mmol dm^-3 s^-1; what was the rate of formation of H₂?

a. 2 mmol dm^-3 s^-1.

Section reference: 9.2

b. 3 mmol dm^-3 s^-1.

Section reference: 9.2

c. 1 mmol dm^-3 s^-1.

Section reference: 9.2

d. 6 mmol dm^-3 s^-1.

Section reference: 9.2

Type: multiple response question

Title: Chapter 09 Question 05

5) Which of the following are elementary reactions? Select all that apply.

Section reference: 9.4

a. H^• +Cl₂ → HCl + Cl^•

b. 2 NO (g) + O₂ (g) → 2NO₂ (g)

c. BrO₃^- (aq) + 5Br^- (aq) + 6H₃O⁺ (aq) → 3Br₂ (aq) + 9H₂O (aq)

d. (CH₃)₃C⁺ + H₂O → [(CH₃)₃COH₂]⁺

Type: matching question

Title: Chapter 09 Question 06

6) For a general reaction aA + bB → products, the rate equation takes the form: rate of reaction = k[A]^a[B]^b. Match each of the following with its short description.

Section reference: 9.4

a. overall order of the reaction = (a + b)

b. order of the reaction with respect to A = a

c. order of the reaction with respect to B = b

d. rate constant = k

Type: multiple response question

Title: Chapter 09 Question 07

7) For a general reaction 2A + 3B → products, the rate equation takes the form: rate of reaction = k [A]²[B]¹. Select all that apply.

Section reference: 9.4

a. The overall order of reaction = 2.

b. The order of reaction with respect to A = 2.

c. The order of the reaction with respect to B = 1.

d. The units of the rate constant k = s^-1.

Type: multiple choice question

Title: Chapter 09 Question 08

8) For the general reaction 2A + B → products, the rate equation takes the following form: rate of reaction = k[A]²[B]¹. What are the units of the rate constant, k?

a. s^-1.

Section reference: 9.4

b. dm³ mol^-1 s^-1.

Section reference: 9.4

c. mol dm^-3 s^-1.

Section reference: 9.4

d. dm⁶ mol^-2 s^-1.

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 09

9) The rate of reaction in the following reaction: 2I (g) + Ar (g) → I₂ (g) + Ar (g) can be defined by which of the following expressions:

a. .

Section reference: 9.4

b. .

Section reference: 9.4

c. .

Section reference: 9.4

d. .

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 10

10) The expression for the rate of reaction for the following elementary reaction NO + O₃ → NO₂ + O₂ is:

a. rate of reaction = k [NO] [O₃].

Section reference: 9.4

b. rate of reaction = k [NO] [O₃]³.

Section reference: 9.4

c. rate of reaction = k [NO₂] [O₂].

Section reference: 9.4

d. rate of reaction = .

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 11

11) Which of the following expressions describes the rate of reaction for the elementary unimolecular process: O₃ → O₂ + O ?

a. Rate of reaction = k [O₂] [O].

Section reference: 9.4

b. Rate of reaction = k [O₃].

Section reference: 9.4

c. Rate of reaction = k [O₃]³ .

Section reference: 9.4

d. Rate of reaction = k [O₂]² [O].

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 12

12) For the following elementary reaction: HF + NH₃ → F^- + NH₄⁺. The rate of consumption of the reactants and rate of formation of products is given by which set of expressions?

a. .

Section reference: 9.4

b. .

Section reference: 9.4

c. .

Section reference: 9.4

d. .

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 13

13) For the following elementary reaction: 2Br^● → Br₂. The rate of consumption of the reactant and rate of formation of product is given by which set of expressions?

a.

Section reference: 9.4

b. .

Section reference: 9.4

c. .

Section reference: 9.4

d. .

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 14

14) For the following gas-phase bimolecular elementary reaction 2Cl^● → Cl₂, which rate equation, expressed in terms of a differential, shows the relationship between the rate of consumption of reactant and rate of reaction?

a.

Section reference: 9.4

b. .

Section reference: 9.4

c.

Section reference: 9.4

d.

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 15

15) 2 N₂O₅ (g) → 4 NO₂ (g) + O2 (g) follows first order reaction kinetics, where the rate of reaction = k [N₂O₅]. The integrated form of the rate equation is:

a. [N₂O₅]_t = [N₂O₅]₀ - kt.

Section reference: 9.4

b. ln[N₂O₅]_t = ln[N₂O₅]₀ - kt .

Section reference: 9.4

c. 2[N₂O₅]_t = [N₂O₅]₀ – kt .

Section reference: 9.4

d. 2ln[N₂O₅]_t = ln[N₂O₅]₀ – kt .

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 16

16) For the reaction 2 N₂O₅ (g) → 4 NO₂ (g) + O₂ (g), the rate constant, k = 3.38 × 10^-5 s^-1. What is the overall reaction order?

a. Zero.

Section reference: 9.4

b. First.

Section reference: 9.4

c. Second.

Section reference: 9.4

d. Third.

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 17

17) For a gas-phase reaction at 308 K, the rate constant k = 0.05 dm³ mol^-1 s^-1. What is the overall reaction order of the reaction?

a. Zero.

Section reference: 9.4

b. First.

Section reference: 9.4

c. Second.

Section reference: 9.4

d. Third.

Section reference: 9.4

Type: multiple response question

Title: Chapter 09 Question 18

18) For a first order elementary reaction A → products, the rate of reaction = k[A]. Select all that apply.

Section reference: 9.4

a. .

b. .

c. ln[A]_t = ln[A]₀ – kt .

d. A plot of [A] versus time, t, will give a straight-line graph.

Type: true-false

Title: Chapter 09 Question 19

19) A second order elementary reaction is characterised by a half life () that gets shorter with the progress of the reaction.

a. True

Section reference: 9.4

b. False

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 20

20) The first order gas-phase process: C₂H₆ → 2 CH₃ has a rate constant, k = 5.36 × 10^-4 s^-1 at 700 °C. If in a reaction vessel, the initial concentration of ethane was 0.05 mol dm^-3, what is its concentration after 250 s?

a. - 0.084 mol dm^-3

Section reference: 9.4

b. 0.034 mol dm^-3

Section reference: 9.4

c. 0.044 mol dm^-3

d. -3.13 mol dm^-3

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 21

21) A first order reaction, with rate constant k = 3.25 × 10^-5 s^-1, at 200 °C, is followed experimentally over a period of 1 hour. The initial concentration of the reactant was 0.0280 mol dm^-3. What was the concentration of the reactant after one hour?

a. 0.0279 mol dm^-3

Section reference: 9.4

b. 0.0249 mol dm^-3

Section reference: 9.4

c. 0.0278 mol dm^-3

Section reference: 9.4

d. -0.089 mol dm^-3

Section reference: 9.4

Type: multiple response question

Title: Chapter 09 Question 22

22) A researcher follows the progress of a reaction and tabulates the concentration of the reactant with respect to time of the reaction. How could the scientist prove that the reaction follows first order kinetics and find the rate constant, k? Select all that apply.

Section reference: 9.4

a. Impossible to do.

b. Plot a graph of [reactant] against time, and find a constant half-life ().

c. Plot a graph of ln[reactant] against time and get a linear plot.

d. Plot a graph of 1/[reactant] against time and get a linear plot.

Type: true-false

Title: Chapter 09 Question 23

23) A researcher follows the progress of a reaction using spectroscopic methods. The half-life, (), is found to depend on the initial concentration of the reactant. This evidence suggests that the reaction is following first order kinetics.

a. True

Section reference: 9.4

b. False

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 24

24) For a first order reaction, the half-life, = 237 s. What is the rate constant, k, of the reaction?

a. It is not possible to determine the rate constant.

Section reference: 9.4

b. 0.0029 s^-1.

Section reference: 9.4

c. 0.0084 s^-1.

Section reference: 9.4

d. 342 s.

Section reference: 9.4

Type: multiple choice question

Title: Chapter 09 Question 25

25) A first order rate constant, k = 3.75 × 10^-2 s^-1. What is the reaction’s half-life,?

a. 18.48 s.

Section reference: 9.4

b. 53.33 s.

Section reference: 9.4

c. 26.67 s.

Section reference: 9.4

d. 0.01875 s^-1.

Section reference: 9.4

Type: multiple response question

Title: Chapter 09 Question 26

26) A reaction has a rate constant, k = 2.55 × 10^-3 mol^-1 dm³ s^-1. Select all that apply.

Section reference: 9.4

a. It is a second order reaction.

b. Double the concentration of the reactant, will quadruple the reaction rate.

c. Its half life = 272 s.

d. Its concentration will decay faster than a first order reaction with the same initial rate.

Type: multiple response question

Title: Chapter 09 Question 27

27) Rate of reaction = [A]²[B]

What information does this give us? Select all that apply.

Section reference: 9.4

a. The overall reaction order is 2.

b. The reactant order with respect to reactant A is 2.

c. If the concentration of reactant B only is doubled, the rate of reaction quadruples.

d. The overall reaction order is 3.

Type: true-false

Title: Chapter 09 Question 28

28) If the rate of reaction = [A]²[B], doubling the concentration of [A] will quadruple the rate of reaction. By doubling the concentration of [A] and the concentration of [B] the rate of reaction will increase 16 fold.

a. True

Section reference: 9.4

b. False

Section reference: 9.4

Type: multiple response question

Title: Chapter 09 Question 29

29) Given the data below, which of the following statements is true?

Select all that apply.

Section reference: 9.4, 9.7

a. The reaction is first order.

b. The reaction is second order.

c. The concentration after 700 seconds will be 0.95 × 10^-2 mol dm^-3.

d. The half-life is independent of temperature.

Type: multiple choice question

Title: Chapter 09 Question 30

30) The rate of reaction depends on the concentration of reactant A only. Calculate the order of the reaction from the data below.

a. Zero order.

Section reference: 9.4, 9.5

b. First order.

Section reference: 9.4, 9.5

c. Second order.

Section reference: 9.4, 9.5

d. Third order.

Section reference: 9.4, 9.5

Type: matching question

Title: Chapter 09 Question 31

31) Match the following brief description with the term used to describe a reaction mechanism and its reaction steps.

Section reference: 9.6, 9.8

a. The step in a reaction mechanism that determines the rate of reaction = rate-determining step

b. A reaction step that involves two molecules = bimolecular

c. The rate of change of concentration of a reactive species, in a sequence of reactions is approximately zero. = steady state approximation

d. A reversible step preceding the rate-determining step = pre-equilibrium

Type: multiple response question

Title: Chapter 09 Question 32

32) In the following reaction sequence the first step is reversible. and k₂ is small relative to k₁ and k_-1. Select all that apply.

Section reference: 9.6

a. where K_c is the equilibrium constant.

b. The rate-determining step is step two: .

c. .

d. .

Type: matching question

Title: Chapter 09 Question 33

33) The Arrhenius equation describes how the rate of reaction of many chemical reactions varies with temperature:. Match the symbol with its description.

Section reference: 9.7

a. k = rate constant

b. E_a = activation energy

c. A = pre-exponential factor

d. R = ideal gas constant

Type: multiple choice question

Title: Chapter 09 Question 34

34) A plot of ln k against has a slope of – 3257 and an intercept of 25. What is the activation energy (E_a) (kJ mol^-1) of the reaction?

a. - 3257.

Section reference: 9.7

b. 27.

Section reference: 9.7

c. 25.

Section reference: 9.7

d. 392.

Section reference: 9.7

Type: multiple choice question

Title: Chapter 09 Question 35

35) A plot of ln (k / s^-1) against has a slope of – 2575 and an intercept of 31.5. What is the pre-exponential factor A (s^-1) of this first order reaction?

a. 31.5.

Section reference: 9.7

b. - 2575.

Section reference: 9.7

c. 21409.

Section reference: 96

d. 4.8 × 10¹³,

Section reference: 9.7

Type: multiple choice question

Title: Chapter 09 Question 36

36) A plot of ln k against has a slope of – 2752 and an intercept of 30. What is the activation energy (E_a) (kJ mol^-1) of the reaction?

a. 30.

Section reference: 9.7

b. 2752.

Section reference: 9.7

c. 23.

Section reference: 9.7

d. 331.

Section reference: 9.7

Type: multiple choice question

Title: Chapter 09 Question 37

37) The activation energy (E_a) of a first order reaction is 70 kJ mol^-1. The rate constant (k₁) at 25 °C is 2.25 × 10^-5 s^-1. What is the rate constant (k₂) (s^-1) at 70 °C?

a. 9.13 × 10^-4.

Section reference: 9.7

b. 2.39 × 10⁸⁹.

Section reference: 9.7

c. 2.26 × 10^-5.

Section reference: 9.7

d. 2.25 × 10^-5.

Section reference: 9.7

Type: multiple choice question

Title: Chapter 09 Question 38

38) The activation energy (E_a) of a first order reaction is 45 kJ mol^-1. The rate constant (k) at 75 °C is 5.75 × 10^-4 s^-1. What is the rate constant (s^-1) at 25 °C?

a. 4.24 × 10^-5.

Section reference: 9.7

b. 5.74 × 10^-4.

Section reference: 9.7

c. 1.19 × 10^-66.

Section reference: 9.7

d. 5.75 × 10^-4.

Section reference: 9.7

Type: multiple choice question

Title: Chapter 09 Question 39

39) At 30 °C and 85 °C the rate constants of a reaction are 3.75 × 10^-5 and 2.72 × 10^-3 s^-1 respectively. What is the activation energy E_a (kJ mol^-1)?

a. 1.65.

Section reference: 9.7

b. - 70.31.

Section reference: 9.7

c. 70.31.

Section reference: 9.7

d. 1.02.

Section reference: 9.7

Type: true-false

Title: Chapter 09 Question 40

40) The activation energy E_a, of a reaction is – 5 kJ mol^-1; this suggests that temperature has no effect on the rate constant k, of the reaction.

a. True

Section reference: 9.7

b. False

Section reference: 9.7

Type: multiple response question

Title: Chapter 09 Question 41

41) Which of the following statements are true with respect to the function of a catalyst in a reaction? Select all that apply.

Section reference: 9.9

a. It increases the rate of reaction.

b. It changes the amount of product formed.

c. It is chemically changed by the reaction.

d. It must be in the same physical state as the reaction in order to function.