Question 1

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?

Accepted Answer

A)   0.73 kJ/mol
B)   58 kJ/mol
C)   140 kJ/mol
D)   580 kJ/mol
E)   > 1000 kJ/molF) C) and D)
G) None of the above

Question 2

All bimolecular reactions are second-order reactions.

Accepted Answer

A) True 
 B)False

Question 3

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?

Accepted Answer

A)   0.0224 hr
B)   0.0645 hr
C)   15.5 hr
D)   22.4 hr
E)   44.7 hrF) A) and E)
G) C) and D)

Question 4

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?

Accepted Answer

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-1F) A) and E)
G) B) and E)

Question 5

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?

Accepted Answer

A)   Zero
B)   First
C)   Second
D)   Third
E)   More information is needed to determine the order.F) B) and D)
G) A) and D)

Question 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

Accepted Answer

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]3F) B) and E)
G) A) and B)

Question 7

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

Accepted Answer

A) True 
 B)False

Question 8

In an exothermic reaction,

Accepted Answer

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.F) C) and E)
G) B) and E)

Question 9

Reaction intermediates differ from activated complexes in that

Accepted Answer

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.F) B) and E)
G) A) and C)

Question 10

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

Accepted Answer

A) True 
 B)False

Question 11

All second-order reactions are bimolecular reactions.

Accepted Answer

A) True 
 B)False

Question 12

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?

Accepted Answer

A)   
B)   7.55 min
C)   481 min
D)   4550 min
E)   31,400 minF) B) and E)
G) A) and B)

Question 13

An increase in temperature increases the reaction rate because

Accepted Answer

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.F) A) and D)
G) A) and C)

Question 14

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

Accepted Answer

A) True 
 B)False

Question 15

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?

Accepted Answer

A)   0.5 kJ/mol
B)   4.5 kJ/mol
C)   7.9 kJ/mol
D)   66 kJ/mol
E)   >100 kJ/molF) All of the above
G) A) and C)

Question 16

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

Accepted Answer

A) True 
 B)False

Question 17

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?

Accepted Answer

A)   0.0109 hr
B)   0.0629 hr
C)   15.9 hr
D)   23.9 hr
E)   91.7 hrF) C) and D)
G) A) and B)

Question 18

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?

Accepted Answer

A)   7.69 × 10-4 s
B)   5.3 × 10-4 s
C)   1.9 × 10-3 s
D)   520 s
E)   1920 sF) C) and D)
G) A) and E)

Question 19

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?

Accepted Answer

A)   2.2 × 10-3 min
B)   5.5 × 10-3 min
C)   180 min
D)   440 min
E)   5.0 × 102 minF) A) and D)
G) A) and B)

Question 20

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?

Accepted Answer

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-1F) A) and B)
G) A) and C)

Exam 16: Kinetics Rates and Mechanisms of Chemical Reactions

All bimolecular reactions are second-order reactions.

Correct Answer
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In an exothermic reaction,

Correct Answer
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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?

Correct Answer
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An increase in temperature increases the reaction rate because

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

Correct Answer
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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?

Correct Answer
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All second-order reactions are bimolecular reactions.

Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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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?

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

Correct Answer
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Reaction intermediates differ from activated complexes in that

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

Correct Answer
verified

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?

Correct Answer
verified

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

Correct Answer
verified

Exam 16: Kinetics Rates and Mechanisms of Chemical Reactions

All bimolecular reactions are second-order reactions.

Correct AnswerverifiedShow Answer

In an exothermic reaction,

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

An increase in temperature increases the reaction rate because

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

All second-order reactions are bimolecular reactions.

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Reaction intermediates differ from activated complexes in that

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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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?

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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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?

Correct Answer
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Correct Answer
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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?

Correct Answer
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Correct Answer
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