Deck 13: Chemical Kinetics

Question 1

Given the following balanced equation, determine the rate of reaction with respect to [SO₃]. 2SO₂(g) + O₂(g) → 2SO₃(g)

A) Rate = -
B) Rate = +
C) Rate = -
D) Rate = +
E) It is not possible to determine the answer without more information.

Answer 1

Rate = +

Question 2

Without performing complex calculations, determine the order of a reaction that has the following initial rates for the specified starting concentration:

A) zero order
B) first order
C) second order
D) third order
E) impossible to determine

Answer 2

second order

Question 3

Given the following balanced equation, determine the rate of reaction with respect to [SO₂]. 2SO₂(g) + O₂(g) → 2SO₃(g)

A) Rate = -
B) Rate = +
C) Rate = -
D) Rate = +
E) It is not possible to determine the answer without more information.

Answer 3

Rate = -

Question 4

Given the following balanced equation, determine the rate of reaction with respect to [SO₃]. If the rate of O₂ loss is 3.56 × 10^-3 mol L^-1 s^-1, what is the rate of formation of SO₃? 2SO₂(g) + O₂(g) → 2SO₃(g)

A) 3.56 × 10^-3 mol L^-1 s^-1
B) 1.19 × 10^-3 mol L^-1 s^-1
C) 1.78 × 10^-3 mol L^-1 s^-1
D) 1.42 × 10^-2 mol L^-1 s^-1
E) 7.12 × 10^-3 mol L^-1 s^-1

Question 5

Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. If the rate of NO loss is 1.68 × 10^-2 mol L^-1 s^-1, what is the rate of formation of NOCl? 2NO(g) + Cl₂(g) → 2NOCl(g)

A) 1.68 × 10^-2 mol L^-1 s^-1
B) 3.81 × 10^-2 mol L^-1 s^-1
C) 5.05 × 10^-2 mol L^-1 s^-1
D) 6.14 × 10^-2 mol L^-1 s^-1
E) 1.45 × 10^-2 mol L^-1 s^-1

Question 6

Given the following balanced equation, determine the rate of reaction with respect to [NH₃]. N₂(g) + 3H₂(g) → 2NH₃(g)

A) Rate = +
B) Rate = -
C) Rate = +
D) Rate = -
E) It is not possible to determine the answer without more information.

Question 7

Given the following balanced equation, determine the rate of reaction with respect to [O₂]. 2O₃(g) → 3O₂(g)

A) Rate = -
B) Rate = -
C) Rate = +
D) Rate = +
E) It is not possible to determine the answer without more information.

Question 8

Write a balanced reaction for which the following rate relationships are true. Rate = = = -

A) N₂ + O₂ → N₂O
B) 2N₂O → 2N₂ + O₂
C) N₂O → N₂ + 2O₂
D) N₂O → N₂ + O₂
E) 2N₂ + O₂ → 2N₂O

Question 9

Without performing complex calculations, determine the order of a reaction that has the following initial rates for the specified starting concentration:

A) zero order
B) first order
C) second order
D) third order
E) impossible to determine

Question 10

Without performing complex calculations, determine the order of a reaction that has the following initial rates for the specified starting concentration:

A) zero order
B) first order
C) second order
D) third order
E) impossible to determine

Question 11

Given the following balanced equation, determine the rate of reaction with respect to [SO₃]. If the rate of SO₂ loss is 1.19 × 10^-3 mol L^-1 s^-1, what is the rate of formation of SO₃? 2SO₂(g) + O₂(g) → 2SO₃(g)

A) 3.56 × 10^-3 mol L^-1 s^-1
B) 1.19 × 10^-3 mol L^-1 s^-1
C) 1.78 × 10^-3 mol L^-1 s^-1
D) 1.42 × 10^-2 mol L^-1 s^-1
E) 7.12 × 10^-3 mol L^-1 s^-1

Question 12

Given the following balanced equation, determine the rate of reaction with respect to [O₂]. 2SO₂(g) + O₂(g) → 2SO₃(g)

A) Rate = -
B) Rate = +
C) Rate = -
D) Rate = +
E) It is not possible to determine the answer without more information.

Question 13

Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. If the rate of Cl₂ loss is 4.84 × 10^-2 mol L^-1 s^-1, what is the rate of formation of NOCl? 2NO(g) + Cl₂(g) → 2NOCl(g)

A) 4.84 × 10^-2 mol L^-1 s^-1
B) 2.42 × 10^-2 mol L^-1 s^-1
C) 1.45 × 10^-1 mol L^-1 s^-1
D) 9.68 × 10^-2 mol L^-1 s^-1
E) 1.61 × 10^-2 mol L^-1 s^-1

Question 14

Write a balanced reaction for which the following rate relationships are true. Rate = - = =

A) 2N₂O₅ → 4NO₂ + O₂
B) 4NO₂ + O₂ → 2N₂O₅
C) 2N₂O₅ → NO₂ + 4O₂
D) NO₂ + O₂ → N₂O₅
E) N₂O_{5 →} NO₂ + O₂

Question 15

Given the following balanced equation, determine the rate of reaction with respect to [O₃]. 2O₃(g) → 3O₂(g)

A) Rate = -
B) Rate = -
C) Rate = +
D) Rate = +
E) It is not possible to determine the answer without more information.

Question 16

Given the following balanced equation, determine the rate of reaction with respect to [O₂]. If the rate of formation of O₂ is 6.94 × 10^-1 mol L^-1 s^-1, what is the rate of the loss of O₃? 2O₃(g) → 3O₂(g)

A) 0.463 mol L^-1 s^-1
B) 1.04 mol L^-1 s^-1
C) 2.08 mol L^-1 s^-1
D) 0.231 mol L^-1 s^-1
E) 4.16 mol L^-1 s^-1

Question 17

Given the following balanced equation, determine the rate of reaction with respect to [O₃]. If the rate of loss of O₃ is 3.91 × 10^-1 mol L^-1 s^-1, what is the rate of the formation of O₂? 2O₃(g) → 3O₂(g)

A) 2.61 mol L^-1 s^-1
B) 0.937 mol L^-1 s^-1
C) 0.261 mol L^-1 s^-1
D) 0.587 mol L^-1 s^-1
E) 0.817 mol L^-1 s^-1

Question 18

Without performing complex calculations, determine the order of a reaction that has the following initial rates for the specified starting concentration:

A) zero order
B) first order
C) second order
D) third order
E) impossible to determine

Question 19

Given the following balanced equation, determine the rate of reaction with respect to [H₂]. N₂(g) + 3H₂(g) → 2NH₃(g)

A) Rate = +
B) Rate = -
C) Rate = +
D) Rate = -
E) It is not possible to determine the answer without more information.

Question 20

Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. 2NO(g) + Cl₂(g) → 2NOCl(g)

A) Rate = -
B) Rate = +
C) Rate = -
D) Rate = -
E) It is not possible to determine the answer without more information.

Question 21

Which of the following is the characteristic of a zero-order reaction having only one reactant?

A) The rate of the reaction is not proportional to the concentration of the reactant.
B) The rate of the reaction is proportional to the square of the concentration of the reactant.
C) The rate of the reaction is proportional to the square root of the concentration of the reactant.
D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant.
E) The rate of the reaction is directly proportional to the concentration of the reactant.

Question 22

What is the unit of k in a first-order reaction?

A) mol L^-1 s^-1
B) mol L^-1 s
C) L mol^-1 s^-1
D) M² s^-1
E) s^-1

Question 23

What is the overall order of the following reaction, given the rate law? NO(g) + O₃(g) → NO₂(g) + O₂(g) Rate = k[NO][O₃]

A) 1st order
B) 2nd order
C) 3rd order
D) 1 order
E) 0th order

Question 24

Determine the missing initial rate for the following order reaction given the following information:

A) 0.0352 mol L^-1 s^-1
B) 0.0301 mol L^-1 s^-1
C) 0.0215 mol L^-1 s^-1
D) 0.0233 mol L^-1 s^-1
E) 0.0280 mol L^-1 s^-1

Question 25

What is the unit of k in the following rate law? Rate = k[X][Y]

A) mol L^-1 s^-1
B) mol L^-1 s
C) L mol^-1 s^-1
D)
E)

Question 26

Determine the missing initial rate for a reaction with an order of given the following information:

A) 6.0 × 10^-3 mol L^-1 s^-1
B) 2.8 × 10^-2 mol L^-1 s^-1
C) 7.3 × 10^-3 mol L^-1 s^-1
D) 9.74 × 10^-3 mol L^-1 s^-1
E) 1.0 × 10^-2 mol L^-1 s^-1

Question 27

What is the unit of k in the following rate law? Rate = k[X][Y]²

A)
B)
C) M² s
D)
E)

Question 28

Without performing complex calculations, determine the order of a reaction that has the following initial rates for the specified starting concentration:

A) zero order
B) first order
C) second order
D) third order
E) impossible to determine

Question 29

What is the unit of k in a zero-order reaction?

A) mol L^-1 s^-1
B) mol L^-1 s
C) L mol^-1 s^-1
D) M² s^-1
E) s^-1

Question 30

What is the unit of k in a second-order reaction?

A) mol L^-1 s^-1
B) mol L^-1 s
C) L mol^-1 s^-1
D) M² s^-1
E) s^-1

Question 31

What is the unit of k in the following rate law? Rate = k[X]²

A) mol L^-1 s^-1
B) mol L^-1 s
C) L mol^-1 s^-1
D) L mol^-2 s^-1
E) M² s^-1

Question 32

Which of the following is the characteristic of a second-order reaction having only one reactant?

A) The rate of the reaction is not proportional to the concentration of the reactant.
B) The rate of the reaction is proportional to the square of the concentration of the reactant.
C) The rate of the reaction is proportional to the square root of the concentration of the reactant.
D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant.
E) The rate of the reaction is directly proportional to the concentration of the reactant.

Question 33

Which of the following is the characteristic of a first-order reaction having only one reactant?

A) The rate of the reaction is not proportional to the concentration of the reactant.
B) The rate of the reaction is proportional to the square of the concentration of the reactant.
C) The rate of the reaction is proportional to the square root of the concentration of the reactant.
D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant.
E) The rate of the reaction is directly proportional to the concentration of the reactant.

Question 34

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]²

A) The rate of reaction will increase by a factor of 2.
B) The rate of reaction will increase by a factor of 4.
C) The rate of reaction will increase by a factor of 5.
D) The rate of reaction will decrease by a factor of 2.
E) The rate of reaction will remain unchanged.

Question 35

What is the overall order of the following reaction, given the rate law? 2 X + 3 Y → 2 Z Rate = k[X]¹[Y]²

A) 3rd order
B) 5th order
C) 2nd order
D) 1st order
E) 0th order

Question 36

What is the overall order of the following reaction, given the rate law? 2NO(g) + H₂(g) → N₂(g) + 2H₂O(g) Rate = k[NO]²[H₂]

A) 1st order
B) 2nd order
C) 3rd order
D) 4th order
E) 0th order

Question 37

Which of the following statements is FALSE?

A) The rate of a chemical reaction is a measure of how fast a reaction occurs.
B) The half-life of a first-order reaction is independent of the initial concentration of reactant.
C) The rate of a zero-order reaction is dependent on the concentration of the reactant.
D) The rate law shows the relationship between the rate and the concentrations of each reactant.
E) The rate order with respect to each reactant must be determined experimentally.

Question 38

What is the overall order of the following reaction, given the rate law? X + 2 Y → 4 Z Rate = k[X][Y]

A) 3rd order
B) 5th order
C) 2nd order
D) 1st order
E) 0th order

Question 39

Determine the missing initial rate for the following order reaction given the following information:

A) 0.48 mol L^-1 s^-1
B) 0.38 mol L^-1 s^-1
C) 0.91 mol L^-1 s^-1
D) 1.3 mol L^-1 s^-1
E) 0.84 mol L^-1 s^-1

Question 40

What is the unit of k in the following rate law? Rate = k[X][Y]^1/2

A) mol L^-1 s^-1
B) L mol^-1 s^-1
C) L mol^-1/2 s^-1
D) L^1/2 mol^-1/2 s^-1
E) L mol^-1 s^-1/2

Question 41

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X]²[Y]³

A) The rate of reaction will increase by a factor of 9.
B) The rate of reaction will increase by a factor of 2.
C) The rate of reaction will increase by a factor of 8.
D) The rate of reaction will increase by a factor of 4.
E) The rate of reaction will remain unchanged.

Question 42

What data should be plotted to show that experimental concentration data fit a first-order reaction?

A) vs. time
B) [reactant] vs. time
C) ln[reactant] vs. time
D) ln(k) vs.
E) ln(k) vs. E_a

Question 43

For a reaction that follows the general rate law Rate = k[A]^1/2[B]², what will happen to the rate of reaction if the concentration of A and B are is increased by a factor of 4?

A) The rate will decrease by a factor of 1/32.0.
B) The rate will decrease by a factor of 1/32.00.
C) The rate will increase by a factor of 32.
D) The rate will increase by a factor of 16.0.

Question 44

What data should be plotted to show that experimental concentration data fit a zeroth-order reaction?

A) ln[reactant] vs. time
B) vs. time
C) ln(k) vs.
D) ln(k) vs. E_a
E) [reactant] vs. time

Question 45

For a reaction that follows the general rate law Rate = k[A]^-1 [B]², what will happen to the rate of reaction if the concentration of A and B are increased by a factor of 6?

A) The rate will decrease by a factor of 1/36.00.
B) The rate will decrease by a factor of 1/6.00.
C) The rate will increase by a factor of 36.00.
D) The rate will increase by a factor of 6.00.

Question 46

For a reaction that follows the general rate law Rate = k[A]⁰[B][C]², what will happen to the rate of reaction if the concentration of A is increased by a factor of 4, the concentration of B is increased by a factor of 2, and the concentration of C is increased by a factor 6?

A) The rate will decrease by a factor of 1/72.00.
B) The rate will decrease by a factor of 1/48.
C) The rate will increase by a factor of 72.
D) The rate will increase by a factor of 48.

Question 47

Which of the following represents the integrated rate law for a first-order reaction?

A) = -kt
B) - = kt
C) [A]_t - [A]₀ = -kt
D) k = Ae^(-E_a/RT)
E) = + lnA

Question 48

Determine the rate law and the value of k for the following reaction using the data provided: 2N₂O₅(g) → 4NO₂(g) + O₂(g) [N₂O₅]_i (M) Initial Rate (M^-1 s^-1)
0)093 4.84 × 10^-4
0)186 9.67 × 10^-4
0)279 1.45 × 10^-3

A) Rate = 5.6 × 10^-2 M^-1 s^-1[N₂O₅]²
B) Rate = 6.0 × 10^-1 M^-2 s^-1[N₂O₅]³
C) Rate = 1.6 × 10^-3 M^1/2 s^-1[N₂O₅]^1/2
D) Rate = 1.7 × 10^-2 M^-1/2 s^-1[N₂O₅]^3/2
E) Rate = 5.2 × 10⁻³ s^-1[N₂O₅]

Question 49

Which of the following represents the equation for a first-order half-life?

A) t _1/2 =
B) t _1/2 =
C) t _1/2 =
D) t _1/2 =
E) t _1/2 =

Question 50

Given the following rate law, how does the rate of reaction change if the concentration of X is doubled? Rate = k [X]²[Y]³

A) The rate of reaction will increase by a factor of 9.
B) The rate of reaction will increase by a factor of 2.
C) The rate of reaction will increase by a factor of 8.
D) The rate of reaction will increase by a factor of 4.
E) The rate of reaction will remain unchanged.

Question 51

Which of the following represents the integrated rate law for a second-order reaction?

A) = -kt
B) - = kt
C) [A]_t - [A]₀ = -kt
D) k = Ae^(-E_a/RT)
E) = + lnA

Question 52

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]

A) The rate of reaction will increase by a factor of 2.
B) The rate of reaction will increase by a factor of 4.
C) The rate of reaction will increase by a factor of 5.
D) The rate of reaction will decrease by a factor of 2.
E) The rate of reaction will remain unchanged.

Question 53

Determine the rate law and the value of k for the following reaction using the data provided: 2NO(g) + O₂(g) → 2NO₂(g) [NO]_i (M) [O₂]_i (M) Initial Rate (M^-1 s^-1)
0)030 0.0055 8.55 × 10^-3
0)030 0.0110 1.71 × 10^-2
0)060 0.0055 3.42 × 10^-2

A) Rate = 57 M^-1 s^-1[NO][O₂]
B) Rate = 3.8 M^-1/2 s^-1[NO][O₂]^1/2
C) Rate = 3.1 × 10⁵ M^-3 s^-1[NO]²[O₂]²
D) Rate = 1.7 × 10³ M^-2 s^-1[NO]²[O₂]
E) Rate = 9.4 × 10³ M^-2 s^-1[NO][O₂]²

Question 54

Which of the following represents the equation for a second-order half-life?

A) t _1/2 =
B) t _1/2 =
C) t _1/2 =
D) t _1/2 =
E) t _1/2 =

Question 55

Which of the following represents the integrated rate law for a zeroth-order reaction?

A) = -kt
B) - = kt
C) [A]_t - [A]₀ = -kt
D) k = Ae^(-E_a/RT)
E) = + lnA

Question 56

What data should be plotted to show that experimental concentration data fit a second-order reaction?

A) ln[reactant] vs. time
B) [reactant] vs. time
C) ln(k) vs.
D) vs. time
E) ln(k) vs. E_a

Question 57

Given the following rate law, how does the rate of reaction change if the concentration of X is doubled? Rate = k [X][Y]²

A) The rate of reaction will increase by a factor of 2.
B) The rate of reaction will increase by a factor of 4.
C) The rate of reaction will increase by a factor of 5.
D) The rate of reaction will decrease by a factor of 2.
E) The rate of reaction will remain unchanged.

Question 58

Determine the rate law and the value of k for the following reaction using the data provided: S₂O₈²⁻(aq) + 3 I⁻(aq) → 2 SO₄²⁻(g) + I₃⁻(aq) [S₂O₈²⁻]_i (M) [I⁻]_i (M) Initial Rate (M^-1 s^-1)
0)30 0.42 4.54
0)44 0.42 6.65
0)44 0.21 3.33

A) Rate = 120 M^-2 s^-1 [S₂O₈²⁻]²[I⁻]
B) Rate = 36 M^-1 s^-1 [S₂O₈²⁻][I⁻]
C) Rate = 86 M^-2 s^-1 [S₂O₈²⁻][I⁻]²
D) Rate = 195 M^-3 s^-1 [S₂O₈²⁻]²[I⁻]²
E) Rate = 23 M^-1/2 s^-1 [S₂O₈²⁻][I⁻]^1/2

Question 59

Determine the rate law and the value of k for the following reaction using the data provided: NO₂(g) + O₃(g) → NO₃(g) + O₂(g) [NO₂]_i (M) [O₃]_i (M) Initial Rate (M^-1 s^-1)
0)10 0.33 1.42
0)10 0.66 2.84
0)25 0.66 7.10

A) Rate = 1360 M^-2.5 s^-1[NO₂]^2.5[O₃]
B) Rate = 227 M^-2.5 s^-1[NO₂][O₃]^2.5
C) Rate = 43 M^-1 s^-1[NO₂][O₃]
D) Rate = 430 M^-2 s^-1[NO₂]²[O₃]
E) Rate = 130 M^-2 s^-1[NO₂][O₃]²

Question 60

Determine the rate law and the value of k for the following reaction using the data provided: CO(g) + Cl₂(g) → COCl₂(g) [CO]_i (M) [Cl₂]_i (M) Initial Rate (M¹ s^-1)
0)25 0.40 0.696
0)25 0.80 1.97
0)50 0.80 3.94

A) Rate = 11 M^-3/2 s^-1 [CO][Cl₂]^3/2
B) Rate = 36 M^-1.8 s^-1 [CO][Cl₂]^2.8
C) Rate = 17 M^-2 s^-1 [CO][Cl₂]²
D) Rate = 4.4 M^-1/2 s^-1 [CO][Cl₂]^1/2
E) Rate = 18 M^-3/2 s^-1 [CO]²[Cl₂]^1/2

Question 61

The first-order decay of radon has a half-life of 3.823 days. How many grams of radon remain after 7.22 days if the sample initially weighs 250.0 grams?

A) 4.21 g
B) 183 g
C) 54.8 g
D) 76.3 g
E) 67.5 g

Question 62

The first-order decay of radon has a half-life of 3.823 days. How many grams of radon decomposes after 5.55 days if the sample initially weighs 100.0 grams?

A) 83.4 g
B) 16.6 g
C) 50.0 g
D) 36.6 g
E) 63.4 g

Question 63

The rate constant for a first-order reaction is 0.54 L mol^-1 s^-1. What is the half-life of this reaction if the initial concentration is 0.27 mol L^-1?

A) 2.0 s
B) 5.0 s
C) 0.25 s
D) 6.9 s
E) 1.3 s

Question 64

How many half-lives are required for the concentration of reactant to decrease to 12.5% of its original value?

A) 3
B) 1
C) 1.75
D) 2.75
E) 2

Question 65

The rate constant for the first-order decomposition of N₂O is 3.40 s^-1. What is the half-life of the decomposition?

A) 0.491 s
B) 0.204 s
C) 0.236 s
D) 0.424 s
E) 0.294 s

Question 66

The first-order decomposition of N₂O at 1000 K has a rate constant of 0.76 s^-1. If the initial concentration of N₂O is 10.9 mol L^-1, what is the concentration of N₂O after 9.6 s?

A) 7.4 × 10^-3 mol L^-1
B) 1.0 × 10^-3 mol L^-1
C) 1.4 × 10^-3 mol L^-1
D) 3.6 × 10^-3 mol L^-1
E) 8.7 × 10^-3 mol L^-1

Question 67

Derive an expression for a "1/4-life" for a first-order reaction.

A)
B)
C)
D)
E)

Question 68

The rate constant for a zero-order reaction is 0.54 L mol^-1 s^-1. What is the half-life of this reaction if the initial concentration is 0.27 mol L^-1?

A) 2.0 s
B) 5.0 s
C) 0.25 s
D) 6.9 s
E) 1.3 s

Question 69

The rate constant for a second-order reaction is 0.54 L mol^-1 s^-1. What is the half-life of this reaction if the initial concentration is 0.27 mol L^-1?

A) 2.0 s
B) 5.0 s
C) 0.25 s
D) 6.9 s
E) 1.3 s

Question 70

Which of the following represents the equation for a zero-order half-life?

A) t _1/2 =
B) t _1/2 =
C) t _1/2 =
D) t _1/2 =
E) t _1/2 =

Question 71

The first-order decomposition of N₂O₅ at 328 K has a rate constant of 1.70 × 10^-3 s^-1. If the initial concentration of N₂O₅ is 2.88 mol L^-1, what is the concentration of N₂O₅ after 12.5 minutes?

A) 0.124 mol L^-1
B) 0.805 mol L^-1
C) 2.82 mol L^-1
D) 0.355 mol L^-1
E) 0.174 mol L^-1

Question 72

How many half-lives are required for the concentration of reactant to decrease to 1.56% of its original value?

A) 6
B) 5
C) 7
D) 6.5
E) 7.5

Question 73

Derive an expression for a "1/3-life" for a first-order reaction.

A)
B)
C)
D)
E)

Question 74

The first-order decomposition of cyclopropane has a rate constant of 6.7 × 10^-4 s^-1. If the initial concentration of cyclopropane is 1.33 mol L^-1, what is the concentration of cyclopropane after 644 s?

A) 0.43 mol L^-1
B) 0.15 mol L^-1
C) 0.94 mol L^-1
D) 0.86 mol L^-1
E) 0.67 mol L^-1

Question 75

The half-life for the decay of radium is 1620 years. What is the rate constant for this first-order process?

A) 4.28 × 10^-4 yr^-1
B) 1.12 × 10^-4 yr^-1
C) 2.33 × 10^-4 yr^-1
D) 8.91 × 10^-4 yr^-1
E) 6.17 × 10^-4 yr^-1

Question 76

Which of the following statements is FALSE?

A) The average rate of a reaction decreases during a reaction.
B) It is not possible to determine the rate of a reaction from its balanced equation.
C) The rate of zero-order reactions is not dependent on concentration.
D) The half-life of a first-order reaction is dependent on the initial concentration of reactant.
E) None of the above statements is false.

Question 77

If the concentration of a reactant is 6.25%, how many half-lives has it gone through?

A) 7
B) 6
C) 3
D) 4
E) 5

Question 78

How many half-lives are required for the concentration of reactant to decrease to 25% of its original value?

A) 1
B) 3
C) 1.5
D) 2.5
E) 2

Question 79

The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI is 0.67 mol L^-1. What is the rate constant for this reaction?

A) 1.0 × 10^-2 L mol^-1 s^-1
B) 4.5 × 10^-2 L mol^-1 s^-1
C) 9.7 × 10^-2 L mol^-1 s^-1
D) 2.2 × 10^-2 L mol^-1 s^-1
E) 3.8 × 10^-2 L mol^-1 s^-1

Question 80

The second-order decomposition of HI has a rate constant of 1.80 × 10^-3 L mol^-1 s^-1. How much HI remains after 27.3 s if the initial concentration of HI is 4.78 mol L^-1?

A) 4.55 mol L^-1
B) 0.258 mol L^-1
C) 3.87 mol L^-1
D) 2.20 mol L^-1
E) 2.39 mol L^-1