Question 1

The rate law is Rate = [HgCl2]x[C2O42-]y. Thus:

Accepted Answer

A)  x = 2, y = 1 
B)  x = 2, y = 2 
C)  x = 1, y = 2 
D)  x = 1, y = 1 
E)  x = 0, y = 2 
A)  x = 2, y = 1 
B)  x = 2, y = 2 
C)  x = 1, y = 2 
D)  x = 1, y = 1 
E)  x = 0, y = 2 C

Question 2

If a catalyst is added to a reaction: 
I. the value of k is increased
II. the value of k is decreased
III. the rate is increased
IV. the rate is decreased
V. neither rate nor the constant are changed, only the order

Accepted Answer

A)  I and IV 
B)  II and IV 
C)  II and III 
D)  I and III 
E)  V only 
A)  I and IV 
B)  II and IV 
C)  II and III 
D)  I and III 
E)  V only D

Question 3

In the first-order, reaction A → products, [A] = 0.400 M initially and 0.250 M after 15.0 min, what is the half-life of the reaction?

Accepted Answer

A)  22.1 min 
B)  63.9 min 
C)  9.62 min 
D)  51.0 min 
E)  15.0 min 
A)  22.1 min 
B)  63.9 min 
C)  9.62 min 
D)  51.0 min 
E)  15.0 min A

Question 4

For the reaction: C2H4Br2 + 3 KI → C2H4 + 2 KBr + KI3, when the rate of reaction is 2.0 × 10-5, what is the rate of disappearance of KI?

Accepted Answer

A)  -0.67 × 10-5 
B)  -2.0 × 10-5 
C)  -4.0 × 10-5 
D)  -6.0 × 10-5 
E)  -1.0 × 10-5 
A)  -0.67 × 10-5 
B)  -2.0 × 10-5 
C)  -4.0 × 10-5 
D)  -6.0 × 10-5 
E)  -1.0 × 10-5

Question 5

The rate constant at 160 °C for the first order decomposition of ore is 0.032/min. The half-life of the reaction is ________.

Accepted Answer

A)  62.5 sec 
B)  31.25 sec 
C)  5000 sec 
D)  111 sec 
E)  1300 sec 
A)  62.5 sec 
B)  31.25 sec 
C)  5000 sec 
D)  111 sec 
E)  1300 sec

Question 6

Choose the INCORRECT statement.

Accepted Answer

A)  The rate-determining step is always the first step. 
B)  A unimolecular process is one in which a single molecule dissociates. 
C)  A bimolecular process is one involving a collision of two molecules. 
D)  A reaction mechanism is a step-by-step detailed description of a chemical reaction. 
E)  An elementary process is a step in the mechanism. 
A)  The rate-determining step is always the first step. 
B)  A unimolecular process is one in which a single molecule dissociates. 
C)  A bimolecular process is one involving a collision of two molecules. 
D)  A reaction mechanism is a step-by-step detailed description of a chemical reaction. 
E)  An elementary process is a step in the mechanism.

Question 7

What is the order of reaction for the following reaction: Rate = k[A]-1/2 [B]1/2 ?

Accepted Answer

A)  first order 
B)  zero order 
C)  1/2 order 
D)  -1/2 order 
E)  second order 
A)  first order 
B)  zero order 
C)  1/2 order 
D)  -1/2 order 
E)  second order

Question 8

What is the main difference between a Pt catalyst and an enzyme catalyst?

Accepted Answer

A)  An enzyme has greater substrate specificity. 
B)  The Pt catalyst causes a faster reaction. 
C)  The enzyme causes a faster reaction. 
D)  A Pt catalyst is always a homogeneous catalyst. 
E)  A Pt catalyst is an enzyme. 
A)  An enzyme has greater substrate specificity. 
B)  The Pt catalyst causes a faster reaction. 
C)  The enzyme causes a faster reaction. 
D)  A Pt catalyst is always a homogeneous catalyst. 
E)  A Pt catalyst is an enzyme.

Question 9

In the reaction C4H9Cl(aq) + H2O(l) → C4H9OH(aq) + HCl(aq) the concentration of the reactant changes from 0.0562 M to 0.0431 M in 85 sec. What is the average rate of decomposition over this interval?

Accepted Answer

A)  1.54 × 10-4 M/s 
B)  1.54 × 10-4 moles 
C)  1.54 × 10-4 moles/s 
D)  0.0154 M 
E)  0.0154 M/s 
A)  1.54 × 10-4 M/s 
B)  1.54 × 10-4 moles 
C)  1.54 × 10-4 moles/s 
D)  0.0154 M 
E)  0.0154 M/s

Question 10

According to the collision theory in gaseous molecules, collision frequency is ________ and reaction is ________ because ________.

Accepted Answer

A)  low, low, molecules are so far apart 
B)  high, high, each collision results in a reaction 
C)  low, low, molecules must collide before they can react 
D)  high, relatively low, only a fraction of the collisions lead to a reaction 
E)  low, high, molecules are moving so fast that each reaction causes many others 
A)  low, low, molecules are so far apart 
B)  high, high, each collision results in a reaction 
C)  low, low, molecules must collide before they can react 
D)  high, relatively low, only a fraction of the collisions lead to a reaction 
E)  low, high, molecules are moving so fast that each reaction causes many others

Question 11

In the Arrhenius equation, ln k = -Ea/RT + ln A, the symbol A denotes:

Accepted Answer

A)  the initial concentration of A 
B)  the activation energy 
C)  the rate constant 
D)  a constant that represents the frequency of collisions with the proper orientation and other steric conditions favorable for a reaction 
E)  the absolute temperature 
A)  the initial concentration of A 
B)  the activation energy 
C)  the rate constant 
D)  a constant that represents the frequency of collisions with the proper orientation and other steric conditions favorable for a reaction 
E)  the absolute temperature

Question 12

Which of the following has no effect on the rate of a reaction?

Accepted Answer

A)  value of ΔH° 
B)  activation energy 
C)  presence of a catalyst 
D)  temperature of reactants 
E)  concentrations of reactants 
A)  value of ΔH° 
B)  activation energy 
C)  presence of a catalyst 
D)  temperature of reactants 
E)  concentrations of reactants

Question 13

For the reaction: C2H4Br2 + 3 KI → C2H4 + 2 KBr + KI3, when the rate of reaction is 2.0 × 10-5, what is the rate of appearance of KBr?

Accepted Answer

A)  0.67 × 10-5 
B)  2.0 × 10-5 
C)  4.0 × 10-5 
D)  6.0 × 10-5 
E)  1.0 × 10-5 
A)  0.67 × 10-5 
B)  2.0 × 10-5 
C)  4.0 × 10-5 
D)  6.0 × 10-5 
E)  1.0 × 10-5

Question 14

In the first-order, reaction A → products, [A] = 0.400 M initially and 0.250 M after 15.0 min, at what time will [A] = 0.200 M?

Accepted Answer

A)  63.9 min 
B)  22.1 min 
C)  9.62 min 
D)  51.0 min 
E)  15.0 min 
A)  63.9 min 
B)  22.1 min 
C)  9.62 min 
D)  51.0 min 
E)  15.0 min

Question 15

In the first order reaction A → products, [A] = 0.400 M initially and 0.250 M after 15.0 min, what will [A] be after 175 min?

Accepted Answer

A)  1.67 × 10-3 M 
B)  1.04 × 10-3 M 
C)  3.70 × 10-2 M 
D)  6.024 × 10-3 M 
E)  2.31 × 10-1 M 
A)  1.67 × 10-3 M 
B)  1.04 × 10-3 M 
C)  3.70 × 10-2 M 
D)  6.024 × 10-3 M 
E)  2.31 × 10-1 M

Question 16

Which is a plausible mechanism for the following reaction if the rate law is Rate = k[O3]2/[O2]? 2O3 → 3O2

Accepted Answer

A)  2O3 → O2 + O4 (Slow) O4 → 2O2 (Fast) 
B)  2O3 → O6 (Slow) O6 → O4 + O2 (Fast)
O4 → 2O2 (Slow) 
C)  2O3 → O4- + O2+ (Slow) O4- → O2 + O2- (Fast)
O2- + O2+ → 2O2 (Slow) 
D)  O3 ⇌ O2 + O∙ (Fast) O∙ + O3 → 2O2 (Slow) 
E)  O3 ⇌ O2+ + O- (Fast) O- + O3 → O2 + O2- (Slow)
O2- + O2+ → 2O2 (Fast) 
A)  2O3 → O2 + O4 (Slow) O4 → 2O2 (Fast) 
B)  2O3 → O6 (Slow) O6 → O4 + O2 (Fast)
O4 → 2O2 (Slow) 
C)  2O3 → O4- + O2+ (Slow) O4- → O2 + O2- (Fast)
O2- + O2+ → 2O2 (Slow) 
D)  O3 ⇌ O2 + O∙ (Fast) O∙ + O3 → 2O2 (Slow) 
E)  O3 ⇌ O2+ + O- (Fast) O- + O3 → O2 + O2- (Slow)
O2- + O2+ → 2O2 (Fast)

Question 17

What is the rate law for the following reaction and its mechanism? 
2HgCl2 + C2O42- → 2Cl- + 2CO2 + Hg2Cl2 (overall reaction)
HgCl2 + C2O42- ⇌ HgCl2C2O42- (Fast)
HgCl2C2O42- + C2O42- → Hg + 2C2O4Cl2- (Slow)
Hg + HgCl2 → Hg2Cl2 (Fast)
2C2O4Cl2- → C2O42- +2Cl- + 2CO2 (Fast)

Accepted Answer

A)  Rate = k[HgCl2][C2O42-] 
B)  Rate = k[HgCl2]2[C2O42-] 
C)  Rate = k[Hg2Cl2] 
D)  Rate = k[HgCl2][C2O42-]2 
E)  Rate = k[HgCl2]2[C2O42-]2 
A)  Rate = k[HgCl2][C2O42-] 
B)  Rate = k[HgCl2]2[C2O42-] 
C)  Rate = k[Hg2Cl2] 
D)  Rate = k[HgCl2][C2O42-]2 
E)  Rate = k[HgCl2]2[C2O42-]2

Question 18

What is the rate law for the following mechanism? N2O + NO → N2ONO (Slow)
N2ONO → N2 + NO2 (Fast)

Accepted Answer

A)  Rate = k[N2O] 
B)  Rate = k[NO] 
C)  Rate = k[N2O][NO] 
D)  Rate = k[N2][NO2] 
E)  Rate = k[N2ONO] 
A)  Rate = k[N2O] 
B)  Rate = k[NO] 
C)  Rate = k[N2O][NO] 
D)  Rate = k[N2][NO2] 
E)  Rate = k[N2ONO]

Question 19

For the reaction: 2N2O5(g) → 4NO2(g) + O2(g) the rate law is:   = k[N2O5] At 300 K, the half-life is 2.50 × 104 seconds and the activation energy is 103.3 kJ/mol. What is the rate constant at 310 K?

Accepted Answer

A)  2.78 × 10-5 s-1 
B)  7.29 × 10-6 s-1 
C)  7.29 × 10-8 s-1 
D)  3.70 × 10-5 s-1 
E)  1.05 × 10-4 s-1 
A)  2.78 × 10-5 s-1 
B)  7.29 × 10-6 s-1 
C)  7.29 × 10-8 s-1 
D)  3.70 × 10-5 s-1 
E)  1.05 × 10-4 s-1

Question 20

Adding a catalyst lowers the activation energy of a reaction.

Accepted Answer

A) True 
 B)False

Exam 14: Chemical Kinetics

The rate law is Rate = [HgCl2]x[C2O42-]y. Thus:

If a catalyst is added to a reaction: I. the value of k is increased II. the value of k is decreased III. the rate is increased IV. the rate is decreased V. neither rate nor the constant are changed, only the order

In the first-order, reaction A → products, [A] = 0.400 M initially and 0.250 M after 15.0 min, what is the half-life of the reaction?

For the reaction: C2H4Br2 + 3 KI → C2H4 + 2 KBr + KI3, when the rate of reaction is 2.0 × 10-5, what is the rate of disappearance of KI?

The rate constant at 160 °C for the first order decomposition of ore is 0.032/min. The half-life of the reaction is ________.

Choose the INCORRECT statement.

What is the order of reaction for the following reaction: Rate = k[A]-1/2 [B]1/2 ?

What is the main difference between a Pt catalyst and an enzyme catalyst?

In the reaction C4H9Cl(aq) + H2O(l) → C4H9OH(aq) + HCl(aq) the concentration of the reactant changes from 0.0562 M to 0.0431 M in 85 sec. What is the average rate of decomposition over this interval?

According to the collision theory in gaseous molecules, collision frequency is ________ and reaction is ________ because ________.

In the Arrhenius equation, ln k = -Ea/RT + ln A, the symbol A denotes:

Which of the following has no effect on the rate of a reaction?

For the reaction: C2H4Br2 + 3 KI → C2H4 + 2 KBr + KI3, when the rate of reaction is 2.0 × 10-5, what is the rate of appearance of KBr?

In the first-order, reaction A → products, [A] = 0.400 M initially and 0.250 M after 15.0 min, at what time will [A] = 0.200 M?

In the first order reaction A → products, [A] = 0.400 M initially and 0.250 M after 15.0 min, what will [A] be after 175 min?

Which is a plausible mechanism for the following reaction if the rate law is Rate = k[O3]2/[O2]? 2O3 → 3O2

What is the rate law for the following reaction and its mechanism? 2HgCl2 + C2O42- → 2Cl- + 2CO2 + Hg2Cl2 (overall reaction) HgCl2 + C2O42- ⇌ HgCl2C2O42- (Fast) HgCl2C2O42- + C2O42- → Hg + 2C2O4Cl2- (Slow) Hg + HgCl2 → Hg2Cl2 (Fast) 2C2O4Cl2- → C2O42- +2Cl- + 2CO2 (Fast)

What is the rate law for the following mechanism? N2O + NO → N2ONO (Slow) N2ONO → N2 + NO2 (Fast)

For the reaction: 2N2O5(g) → 4NO2(g) + O2(g) the rate law is: = k[N2O5] At 300 K, the half-life is 2.50 × 104 seconds and the activation energy is 103.3 kJ/mol. What is the rate constant at 310 K?

Adding a catalyst lowers the activation energy of a reaction.

Matter - Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Additional Aspects

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

Electrochemistry

Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry 1-41

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

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The rate law is Rate = [HgCl₂]x[C₂O₄^2-]y. Thus:

For the reaction: C₂H₄Br₂ + 3 KI → C₂H₄ + 2 KBr + KI₃, when the rate of reaction is 2.0 × 10^-5, what is the rate of disappearance of KI?

In the reaction C₄H₉Cl(aq) + H₂O(l) → C₄H₉OH(aq) + HCl(aq) the concentration of the reactant changes from 0.0562 M to 0.0431 M in 85 sec. What is the average rate of decomposition over this interval?

According to the collision theory in gaseous molecules, collision frequency is and reaction is because .

For the reaction: C₂H₄Br₂ + 3 KI → C₂H₄ + 2 KBr + KI₃, when the rate of reaction is 2.0 × 10^-5, what is the rate of appearance of KBr?

Which is a plausible mechanism for the following reaction if the rate law is Rate = k[O₃]2/[O₂]? 2O₃ → 3O₂

What is the rate law for the following mechanism? N₂O + NO → N₂ONO (Slow) N₂ONO → N₂ + NO₂ (Fast)

For the reaction: 2N₂O₅(g) → 4NO₂(g) + O₂(g) the rate law is: = k[N₂O₅] At 300 K, the half-life is 2.50 × 10⁴ seconds and the activation energy is 103.3 kJ/mol. What is the rate constant at 310 K?