Deck 13: Chemical Kinetics

Question 1

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

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

Answer 1

2 N₂O → 2 N₂ + O₂

Question 2

Give 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.

Answer 2

The rate of the reaction is directly proportional to the concentration of the reactant.

Question 3

What are the units of k in a first order reaction?

A)
B)M∙s
C)M^-1s^-1
D)
E)

Answer 3

Question 4

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

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

Question 5

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 M/s,what is the rate of formation of NOCl?
2 NO(g)+ Cl₂(g)→ 2 NOCl(g)

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

Question 6

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

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

Question 7

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

A)
B)
C)M² s
D)
E)

Question 8

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

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

Question 9

What are the units of k in the following rate law?
Rate = k[X][Y]

A)
B)Ms
C)M^-1s^-1
D)
E)

Question 10

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 11

Give 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 12

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 M/s,what is the rate of formation of SO₃?
2 SO₂(g)+ O₂(g)→ 2 SO₃(g)

A)3.56 × 10^-3 M/s
B)1.19 × 10^-3 M/s
C)1.78 × 10^-3 M/s
D)1.42 × 10^-2 M/s
E)7.12 × 10^-3 M/s

Question 13

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

A)3rd order
B)5th order
C)2nd order
D)1st order
E)6th order

Question 14

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)zeroth order

Question 15

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

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

Question 16

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 17

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

A)2 N₂O₅ → 4 NO₂ + O₂
B)4 NO₂ + O₂ → 2 N₂O₅
C)2 N₂O₅ → NO₂ + 4 O₂
D) NO₂ + O₂ →N₂O₅
E) N₂O₅ → NO₂ + O₂

Question 18

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

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

Question 19

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 M/s,what is the rate of the loss of O₃?
2 O₃(g)→ 3 O₂(g)

A)0.463 M/s
B)1.04 M/s
C)2.08 M/s
D)0.231 M/s
E)4.16 M/s

Question 20

What are the units of k in a zeroth order reaction?

A)
B)M∙s
C)M^-1s^-1
D)
E)

Question 21

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 22

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 23

What are the units of k in the following rate law?
Rate = k[X]²

A)M∙s^-1
B)M∙s
C)M^-1s^-1
D)M^-2s^-1
E)M²s^-1

Question 24

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 25

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

A)
B)
C)[A]_t - [A]_o = - kt
D)k = Ae^(-Ea/RT)
E)

Question 26

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

A)ln[reactant] vs.time
B)[reactant] vs.time
C)ln(k)vs.1/T
D)1/[reactant] vs.time
E)ln(k)vs.E_a

Question 27

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 statements are false.

Question 28

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 29

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

A)ln[reactant] vs.time
B)1/[reactant] vs.time
C)ln(k)vs.1/T
D)ln(k)vs.E_a
E)[reactant] vs.time

Question 30

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)

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

Question 31

Determine the rate law and the value of k for the following reaction using the data provided.
2 NO(g)+ O₂(g)→ 2 NO₂(g)

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

Question 32

Given the following rate law,how does the rate of reaction change if the concentration of X is halved and 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 33

Determine the rate law and the value of k for the following reaction using the data provided.
CO(g)+ Cl₂(g)→ COCl₂(g)

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

Question 34

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

A)1/[reactant] vs.time
B)[reactant] vs.time
C)ln[reactant] vs.time
D)ln(k)vs.1/T
E)ln(k)vs.E_a

Question 35

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

A)
B)
C)
D)
E)

Question 36

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

A)
B)
C)
D)k = Ae^(-Ea/RT)
E)

Question 37

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

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

Question 38

Determine the rate law and the value of k for the following reaction using the data provided.
2 N₂O₅(g)→ 4 NO₂(g)+ O₂(g)

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

Question 39

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 40

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)

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

Question 41

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 M,what is the concentration of cyclopropane after 644 s?

A)0.43 M
B)0.15 M
C)0.94 M
D)0.86 M
E)0.67 M

Question 42

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

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

Question 43

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

A)
B)
C)
D)
E)

Question 44

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

A)2.0 s
B)5.0 s
C)1.7 s
D)6.9 s
E)1.3 s

Question 45

How many half-lives are required for the concentration of reactant to decrease to 3.1% of its original value?

A)3
B)1
C)5
D)2.75
E)2

Question 46

Which rate law is ternary?

A)rate = k[A][B]²
B)rate = k [A][B]
C)rate = k [A]
D)rate = k [A][B][C][D]
E)rate = k [A]²

Question 47

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

A)4.55 M
B)0.258 M
C)3.87 M
D)2.20 M
E)2.39 M

Question 48

Which of the following reactions would you predict to have the largest orientation factor?

A)NOF(g)+ NOF(g)→ 2NO(g)+ F₂(g)
B)Br₂(g)+ H₂C=CH₂(g)→ H₂BrC-CBrH₂(g)
C)NH₃(g)+ BCl₃(g)→ H₃N-BCl₃(g)
D)H(g)+ Cl(g)→ HCl(g)
E)All of these reactions should have nearly identical orientation factors.

Question 49

A reaction is followed and found to have a rate constant of 3.36 × 10⁴ M^-1s^-1 at 344 K and a rate constant of 7.69 M^-1s^-1 at 219 K.Determine the activation energy for this reaction.

A)23.8 kJ/mol
B)42.0 kJ/mol
C)11.5 kJ/mol
D)12.5 kJ/mol
E)58.2 kJ/mol

Question 50

Which of the following reactions would you predict to have the smallest orientation factor?

A)X₂ + Y₂ → 2 XY
B)NOCl₂ + NO → 2NOCl
C)N₂ + O₂ → 2 NO
D)N + O₂ → NO₂
E)All of these reactions should have nearly identical orientation factors.

Question 51

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 M,what is the concentration of N₂O₅ after 12.5 minutes?

A)0.124 M
B)0.805 M
C)2.82 M
D)0.355 M
E)0.174 M

Question 52

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

A)
B)
C)
D)
E)

Question 53

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 54

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 55

The first-order rearrangement of CH₃NC is measured to have a rate constant of 3.61 × 10^-15 s^-1 at 298 K and a rate constant of 8.66 × 10^-7 s^-1 at 425 K.Determine the activation energy for this reaction.

A)160.kJ/mol
B)240.kJ/mol
C)417 kJ/mol
D)127 kJ/mol
E)338 kJ/mol

Question 56

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 57

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 58

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 59

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 M,what is the concentration of N₂O after 9.6 s?

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

Question 60

The second-order decomposition of NO₂ has a rate constant of 0.255 M^-1s^-1.How much NO₂ decomposes in 4.00 s if the initial concentration of NO₂ (1.00 L volume)is 1.33 M?

A)1.8 mol
B)0.85 mol
C)0.48 mol
D)0.77 mol
E)0.56 mol

Question 61

A reaction is found to have an activation energy of 38.0 kJ/mol.If the rate constant for this reaction is 1.60 × 10² M^-1s^-1 at 249 K,what is the rate constant at 436 K?

A)2.38 × 10⁵ M^-1s^-1
B)1.26 × 10³ M^-1s^-1
C)7.94 × 10⁴ M^-1s^-1
D)4.20 × 10⁵ M^-1s^-1
E)3.80 × 10⁴ M^-1s^-1

Question 62

Is the activation energy for a forward reaction the same as the activation energy for the reverse of the same reaction?

Question 63

A reaction is found to have an activation energy of 108 kJ/mol.If the rate constant for this reaction is 4.60 × 10^-6 s^-1 at 275 K,what is the rate constant at 366 K?

A)12 s^-1
B)1.7 s^-1
C)0.58 s^-1
D)5.4 × 10^-5 s^-1
E)1.9 × 10^-4 s^-1

Question 64

If the activation energy for a given compound is found to be 103 kJ/mol,with a frequency factor of
4.0 × 10¹³ s^-1,what is the rate constant for this reaction at 398 K?

A)1.2 s^-1
B)8.2 s^-1
C)3.9 × 10¹⁰ s^-1
D)1.7 × 10¹⁰ s^-1
E)2.5 × 10⁷ s^-1

Question 65

Match the following.
t_1/2

A)frequency factor
B)activation energy
C)half-life
D)rate constant
E)reaction order

Question 66

What is a catalyst and what function does it serve?

Question 67

Match the following.
n,in Rate = k[A]ⁿ

A)frequency factor
B)activation energy
C)half-life
D)rate constant
E)reaction order

Question 68

Given the following proposed mechanism,predict the rate law for the overall reaction.
A₂ + 2B → 2AB (overall reaction)
Mechanism
A₂ ⇌ 2A fast
A + B → AB slow

A)Rate = k[A][B]
B)Rate = k[A₂][B]
C)Rate = k[A₂][B]^1/2
D)Rate = k[A₂]
E)Rate = k [A₂]^1/2[B]

Question 69

What function do enzymes serve?

Question 70

Which of the following statements is true?

A)The rate constant does not depend on the activation energy for a reaction where the products are lower in energy than the reactants.
B)A catalyst raises the activation energy of a reaction.
C)Rate constants are temperature dependent.
D)The addition of a homogeneous catalyst does not change the activation energy of a given reaction.
E)None of the above are true.

Question 71

Define half-life.

Question 72

Explain what the exponential factor in the Arrhenius equation represents.

Question 73

What is the difference between average reaction rate and instantaneous reaction rate?

Question 74

If the activation energy for a given compound is found to be 42.0 kJ/mol,with a frequency factor of
8.0 × 10¹⁰ s^-1,what is the rate constant for this reaction at 298 K?

A)2.9 × 10^-4 s^-1
B)7.4 × 10^-4 s^-1
C)1.4 × 10⁹ s^-1
D)4.6 × 10 ⁵ s^-1
E)3.5 × 10³ s^-1

Question 75

Match the following.
A

A)frequency factor
B)activation energy
C)half-life
D)rate constant
E)reaction order

Question 76

Given the following proposed mechanism,predict the rate law for the overall reaction.
2NO₂ + Cl₂ → 2NO₂Cl (overall reaction)
Mechanism
NO₂ + Cl₂ → NO₂Cl + Cl slow
NO₂ + Cl → NO₂Cl fast

A)Rate = k[NO₂][Cl₂]
B)Rate = k[NO₂]²[Cl₂]
C)Rate = k[NO₂][Cl]
D)Rate = k[NO₂Cl][Cl]
E)Rate = k[NO₂Cl]²

Question 77

Identify an homogeneous catalyst.

A)SO₂ over vanadium (V)oxide
B)Pd in H₂ gas
C)Pt with methane
D)H₂SO₄ with concentrated HCl
E)N₂ and H₂ catalyzed by Fe

Question 78

Identify an heterogeneous catalyst.

A)CFCs with ozone
B)Pd in H₂ gas
C)KI dissolved in H₂O₂
D)H₂SO₄ with concentrated HCl
E)H₃PO₄ with an alcohol

Question 79

Match the following.
k

A)frequency factor
B)activation energy
C)half-life
D)rate constant
E)reaction order

Question 80

Match the following.
E_a

A)frequency factor
B)activation energy
C)half-life
D)rate constant
E)reaction order