Question 1

Choose the INCORRECT statement.

Accepted Answer

A)  A reaction intermediate is produced and used up during the reaction. 
B)  A transition state and a reaction intermediate are the same. 
C)  An activated complex has partially formed bonds. 
D)  A reaction intermediates have fully formed bonds. 
E)  The rate-determining step is the slow-step. 
A)  A reaction intermediate is produced and used up during the reaction. 
B)  A transition state and a reaction intermediate are the same. 
C)  An activated complex has partially formed bonds. 
D)  A reaction intermediates have fully formed bonds. 
E)  The rate-determining step is the slow-step.

Question 2

Define rate law.

Accepted Answer

A)  A theoretical equation that describes how the rate of reaction depends on the concentration of reactants. 
B)  An experimentally determined equation that describes how the rate of reaction depends on the concentration of reactants. 
C)  A theoretical equation that describes how the rate of reaction depends on temperature, orientation and number of collisions. 
D)  An experimentally determined equation that describes how the rate of reaction depends on temperature, orientation and number of collisions. 
E)  A statement that describes how the ratio of reaction depends on concentration of reactants developed from the balanced equation. 
A)  A theoretical equation that describes how the rate of reaction depends on the concentration of reactants. 
B)  An experimentally determined equation that describes how the rate of reaction depends on the concentration of reactants. 
C)  A theoretical equation that describes how the rate of reaction depends on temperature, orientation and number of collisions. 
D)  An experimentally determined equation that describes how the rate of reaction depends on temperature, orientation and number of collisions. 
E)  A statement that describes how the ratio of reaction depends on concentration of reactants developed from the balanced equation.

Question 3

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 O2. At the time when N2O5 is being consumed at a rate of -1.2 × 10-4 M/s, what is the rate at which NO2 is being formed?

Accepted Answer

A)  1.2 × 10-4 M/s 
B)  2.4 × 10-4 M/s 
C)  6.0 × 10-5 M/s 
D)  3.0 × 10-5 M/s 
E)  4.8 × 10-4 M/s 
A)  1.2 × 10-4 M/s 
B)  2.4 × 10-4 M/s 
C)  6.0 × 10-5 M/s 
D)  3.0 × 10-5 M/s 
E)  4.8 × 10-4 M/s

Question 4

If a reaction is first order with a rate constant of 5.48 × 10-2/sec, how long is required for 3/4 of the initial concentration of reactant to be used up?

Accepted Answer

A)  25.3 sec 
B)  36.5 sec 
C)  6.3 sec 
D)  18.2 sec 
E)  50.6 sec 
A)  25.3 sec 
B)  36.5 sec 
C)  6.3 sec 
D)  18.2 sec 
E)  50.6 sec

Question 5

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

Accepted Answer

A)  3.06 min-1 
B)  0.0136 min-1 
C)  -0.0313 min-1 
D)  7.05 min-1 
E)  0.0313 min-1 
A)  3.06 min-1 
B)  0.0136 min-1 
C)  -0.0313 min-1 
D)  7.05 min-1 
E)  0.0313 min-1

Question 6

If a reaction has a rate equation of rate = k[A][B][C] then it is:

Accepted Answer

A)  overall second order 
B)  overall first order 
C)  overall third order 
D)  zero order in A 
E)  second order in B 
A)  overall second order 
B)  overall first order 
C)  overall third order 
D)  zero order in A 
E)  second order in B

Question 7

The reaction 2H2 + NO → H2O + 1/2N2 is first order in H2 and second order in NO. The rate law is ________.

Accepted Answer

A)  k[H2]2[NO] 
B)  k[H2][NO]2 
C)  k[H2] 
D)  k[H2][NO] 
E)  k[H2][NO]-2 
A)  k[H2]2[NO] 
B)  k[H2][NO]2 
C)  k[H2] 
D)  k[H2][NO] 
E)  k[H2][NO]-2

Question 8

For a reaction with a second order rate constant, what is the correct unit?

Accepted Answer

A)  M ∙ time-1 
B)  M-1 ∙ time-1 
C)  1 
D)  M-2 ∙ time 
E)  M ∙ time-2 
A)  M ∙ time-1 
B)  M-1 ∙ time-1 
C)  1 
D)  M-2 ∙ time 
E)  M ∙ time-2

Question 9

The reaction A + B → C + D is second order in A and zero order in B. The value of k is 0.012 M-1 min-1. What is the rate of this reaction when [A] = 0.125 M and [B] = 0.435 M?

Accepted Answer

A)  5 × 10-4 M min-1 
B)  3.4 × 10-3 M min-1 
C)  1.3 M min-1 
D)  1.9 × 10-4 M min-1 
E)  1.5 × 10-3 M min-1 
A)  5 × 10-4 M min-1 
B)  3.4 × 10-3 M min-1 
C)  1.3 M min-1 
D)  1.9 × 10-4 M min-1 
E)  1.5 × 10-3 M min-1

Question 10

In a second order reaction: 
I. the sum of the exponents in the rate law is equal to two.
II. at least one of the exponents in the rate law is a two.
III. the half-life is not constant.
IV. the half-life is constant.
V. k can be expressed as M-2s-1 or M-2min-1.

Accepted Answer

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

Question 11

Which of the following statements is INCORRECT?

Accepted Answer

A)  Radioactive decay is a first order reaction. 
B)  Half-life in a first order reaction is constant. 
C)  For a first order reaction ln [A]t/[A]o = kt. 
D)  In gaseous reactions [A] can be expressed as concentration or as pressure. 
E)  In a zero order reaction the rate remains constant throughout the reaction. 
A)  Radioactive decay is a first order reaction. 
B)  Half-life in a first order reaction is constant. 
C)  For a first order reaction ln [A]t/[A]o = kt. 
D)  In gaseous reactions [A] can be expressed as concentration or as pressure. 
E)  In a zero order reaction the rate remains constant throughout the reaction.

Question 12

What is the rate constant at 305 K for the reaction: 2N2O5 → 2N2O4 + O2,
If k = 3.46 × 10-5 s-1 at 298 K and Ea = 106 kJ/mol?

Accepted Answer

A)  2.4 × 10-5 s-1 
B)  4.8 × 10-5 s-1 
C)  6.0 × 10-5 s-1 
D)  1.2 × 10-5 s-1 
E)  9.2 × 10-5 s-1 
A)  2.4 × 10-5 s-1 
B)  4.8 × 10-5 s-1 
C)  6.0 × 10-5 s-1 
D)  1.2 × 10-5 s-1 
E)  9.2 × 10-5 s-1

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 C2H4?

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

The reaction has the rate law Rate = k[A][B]2. Which will cause the rate to increase the most?

Accepted Answer

A)  doubling [A] 
B)  lowering temperature 
C)  tripling [B] 
D)  quadrupling [A] 
E)  doubling [B] 
A)  doubling [A] 
B)  lowering temperature 
C)  tripling [B] 
D)  quadrupling [A] 
E)  doubling [B]

Question 15

Which statement is INCORRECT?

Accepted Answer

A)  Activation energy is the same for forward and reverse reaction. 
B)  If the forward reaction is endothermic, the reverse will be exothermic. 
C)  In an endothermic reaction, activation energy is usually greater than the enthalpy. 
D)  An activated complex has higher energy than any molecule contributing to it. 
E)  The activated complex will be the highest on the energy profile. 
A)  Activation energy is the same for forward and reverse reaction. 
B)  If the forward reaction is endothermic, the reverse will be exothermic. 
C)  In an endothermic reaction, activation energy is usually greater than the enthalpy. 
D)  An activated complex has higher energy than any molecule contributing to it. 
E)  The activated complex will be the highest on the energy profile.

Question 16

Which of the following situations involves a heterogeneous catalysis?

Accepted Answer

A)  The catalyst is present in a different phase of matter than are the reactants and products. 
B)  The catalyst is in two different phases of matter. 
C)  The reactants and products are different phases of matter in a catalyzed reaction. 
D)  The catalyst, reactants, and products are all different phases of matter. 
E)  The catalyst changes phases during the reaction. 
A)  The catalyst is present in a different phase of matter than are the reactants and products. 
B)  The catalyst is in two different phases of matter. 
C)  The reactants and products are different phases of matter in a catalyzed reaction. 
D)  The catalyst, reactants, and products are all different phases of matter. 
E)  The catalyst changes phases during the reaction.

Question 17

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. At what temperature is the half-life 400. seconds?

Accepted Answer

A)  273 K 
B)  333 K 
C)  3.04 K 
D)  304 K 
E)  296 K 
A)  273 K 
B)  333 K 
C)  3.04 K 
D)  304 K 
E)  296 K

Question 18

The first-order reaction A → Products has a half-life, t1/2, of 55.0 min at 25°C and 6.8 min at 100°C. What is the activation energy for this reaction?

Accepted Answer

A)  -25.8 kJ/mol 
B)  -38.8 kJ/mol 
C)  347 kJ/mol 
D)  25.8 kJ/mol 
E)  38.8 kJ/mol 
A)  -25.8 kJ/mol 
B)  -38.8 kJ/mol 
C)  347 kJ/mol 
D)  25.8 kJ/mol 
E)  38.8 kJ/mol

Question 19

The rate law is Rate = k[NO]x[O2]y:

Accepted Answer

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

Question 20

If increasing the concentration of A in a chemical reaction causes no increase in the rate of the reaction, then we may say the reaction rate is first order in [A].

Accepted Answer

A) True 
 B)False

Exam 14: Chemical Kinetics

Choose the INCORRECT statement.

Define rate law.

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 O2. At the time when N2O5 is being consumed at a rate of -1.2 × 10-4 M/s, what is the rate at which NO2 is being formed?

If a reaction is first order with a rate constant of 5.48 × 10-2/sec, how long is required for 3/4 of the initial concentration of reactant to be used up?

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

If a reaction has a rate equation of rate = k[A][B][C] then it is:

The reaction 2H2 + NO → H2O + 1/2N2 is first order in H2 and second order in NO. The rate law is ________.

For a reaction with a second order rate constant, what is the correct unit?

The reaction A + B → C + D is second order in A and zero order in B. The value of k is 0.012 M-1 min-1. What is the rate of this reaction when [A] = 0.125 M and [B] = 0.435 M?

In a second order reaction: I. the sum of the exponents in the rate law is equal to two. II. at least one of the exponents in the rate law is a two. III. the half-life is not constant. IV. the half-life is constant. V. k can be expressed as M-2s-1 or M-2min-1.

Which of the following statements is INCORRECT?

What is the rate constant at 305 K for the reaction: 2N2O5 → 2N2O4 + O2, If k = 3.46 × 10-5 s-1 at 298 K and Ea = 106 kJ/mol?

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 C2H4?

The reaction has the rate law Rate = k[A][B]2. Which will cause the rate to increase the most?

Which statement is INCORRECT?

Which of the following situations involves a heterogeneous catalysis?

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. At what temperature is the half-life 400. seconds?

The first-order reaction A → Products has a half-life, t1/2, of 55.0 min at 25°C and 6.8 min at 100°C. What is the activation energy for this reaction?

The rate law is Rate = k[NO]x[O2]y:

If increasing the concentration of A in a chemical reaction causes no increase in the rate of the reaction, then we may say the reaction rate is first order in [A].

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

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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

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If a reaction is first order with a rate constant of 5.48 × 10^-2/sec, how long is required for 3/4 of the initial concentration of reactant to be used up?

The reaction 2H₂ + NO → H₂O + 1/2N₂ is first order in H₂ and second order in NO. The rate law is ________.

In a second order reaction: I. the sum of the exponents in the rate law is equal to two. II. at least one of the exponents in the rate law is a two. III. the half-life is not constant. IV. the half-life is constant. V. k can be expressed as M^-2s^-1 or M^-2min^-1.

What is the rate constant at 305 K for the reaction: 2N₂O₅→ 2N₂O₄+ O₂, If k = 3.46 × 10^-5 s^-1 at 298 K and Ea = 106 kJ/mol?

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 C₂H₄?

For the reaction: 2N₂O₅(g) → 4NO₂(g) + O₂(g) the rate law is: = k[N₂O₅] At 300 K, the half-life is 2.50 × 10⁴seconds and the activation energy is 103.3 kJ/mol. At what temperature is the half-life 400. seconds?

The rate law is Rate = k[NO]x[O₂]y: