Question 1

Consider the reaction 2NH3(g) → N2(g) + 3H2(g)
If the rate Δ[H2]/Δt is 0.030 mol L-1s-1, then Δ[NH3 ]/Δt is

Accepted Answer

A)  -0.045 mol L-1 s-1 
B)  -0.030 mol L-1 s-1 
C)  -0.020 mol L-1 s-1 
D)  -0.010 mol L-1 s-1 
E)  None of these choices are correct. 
A)  -0.045 mol L-1 s-1 
B)  -0.030 mol L-1 s-1 
C)  -0.020 mol L-1 s-1 
D)  -0.010 mol L-1 s-1 
E)  None of these choices are correct.

Question 2

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

Accepted Answer

A) True 
 B)False

Question 3

The decomposition of dinitrogen pentaoxide to nitrogen dioxide and oxygen follows first-order kinetics and has an activation energy of 102 kJ/mol. By what factor will the fraction of collisions with energy greater than or equal to the activation energy increase if the reaction temperature goes from 30°C to 60°C?

Accepted Answer

A)  1.00 
B)  1.10 
C)  2.00 
D)  4.00 
E)  38.4 
A)  1.00 
B)  1.10 
C)  2.00 
D)  4.00 
E)  38.4

Question 4

In going from room temperature (25.0°C) to 10°C above room temperature, the rate of a reaction doubles. Calculate the activation energy for the reaction.

Accepted Answer

A)  157.2 kJ/mol 
B)  103.8 kJ/mol 
C)  52.9 kJ/mol 
D)  6.4 kJ/mol 
E)  <1 kJ/mol 
A)  157.2 kJ/mol 
B)  103.8 kJ/mol 
C)  52.9 kJ/mol 
D)  6.4 kJ/mol 
E)  <1 kJ/mol

Question 5

If the activation energy of a reaction decreases by 10.0 kJ/mol, from 100.0 to 90.0 kJ/mol, what effect will this have on the rate of reaction at 298K?

Accepted Answer

A)  The rate will increase, by a factor of more than 50. 
B)  The rate will decrease, by a factor of more than 50. 
C)  The rate will increase, by a factor of less than 50. 
D)  The rate will decrease, by a factor of less than 50. 
E)  The rate will not change unless temperature changes. 
A)  The rate will increase, by a factor of more than 50. 
B)  The rate will decrease, by a factor of more than 50. 
C)  The rate will increase, by a factor of less than 50. 
D)  The rate will decrease, by a factor of less than 50. 
E)  The rate will not change unless temperature changes.

Question 6

Consider the following reaction 8A(g) + 5B(g) → 8C(g) + 6D(g)
If [C] is increasing at the rate of 4.0 mol L-1s-1, at what rate is [B] changing?

Accepted Answer

A)  -0.40 mol L-1s-1 
B)  -2.5 mol L-1s-1 
C)  -4.0 mol L-1s-1 
D)  -6.4 mol L-1s-1 
E)  None of these choices are correct. 
A)  -0.40 mol L-1s-1 
B)  -2.5 mol L-1s-1 
C)  -4.0 mol L-1s-1 
D)  -6.4 mol L-1s-1 
E)  None of these choices are correct.

Question 7

The reaction of ethylene (C2H4) with butadiene (C4H6=) to form cyclohexene (C6H10) has an activation energy (Ea) of 115 kJ/mol. The reverse reaction (decomposition of cyclohexene to ethylene and butadiene) has an activation energy of 287 kJ/mol. What is the heat of reaction, Δ Hrxn, for the forward reaction?

Accepted Answer

A)  +115 kJ/mol 
B)  +287 kJ/mol 
C)  -287 kJ/mol 
D)  +172 kJ/mol 
E)  -172 kJ/mol 
A)  +115 kJ/mol 
B)  +287 kJ/mol 
C)  -287 kJ/mol 
D)  +172 kJ/mol 
E)  -172 kJ/mol

Question 8

Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?

Accepted Answer

A)  24.5 kJ/mol 
B)  165 kJ/mol 
C)  242 kJ/mol 
D)  1630 kJ/mol 
E)  > 104 kJ/mol 
A)  24.5 kJ/mol 
B)  165 kJ/mol 
C)  242 kJ/mol 
D)  1630 kJ/mol 
E)  > 104 kJ/mol

Question 9

A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 × 1020 molecules of reactant at time t = 0, how many molecules remain unreacted after 100.0 minutes?

Accepted Answer

A)  1.00 × 104 molecules 
B)  2.00 × 1019 molecules 
C)  3.20 × 1016 molecules 
D)  5.00 × 1020 molecules 
E)  None of these choices are correct. 
A)  1.00 × 104 molecules 
B)  2.00 × 1019 molecules 
C)  3.20 × 1016 molecules 
D)  5.00 × 1020 molecules 
E)  None of these choices are correct.

Question 10

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10-4 mol L-1 and the rate constant k = 1.08 × 10-6 s-1, what concentration of R remains after 25 days?

Accepted Answer

A)  1.0 × 10-3 mol L-1 
B)  1.0 × 10-4 mol L-1 
C)  9.6 × 10-5 mol L-1 
D)  4.3 × 10-5 mol L-1 
E)  9.7 × 10-6 mol L-1 
A)  1.0 × 10-3 mol L-1 
B)  1.0 × 10-4 mol L-1 
C)  9.6 × 10-5 mol L-1 
D)  4.3 × 10-5 mol L-1 
E)  9.7 × 10-6 mol L-1

Question 11

The active ingredient in an over the counter pain killer analgesic decomposes with a rate constant, k = 9.05 × 10-4 day-1. How many days does it take for 15% of the original ingredient to decompose?

Accepted Answer

A)  730 days 
B)  414 days 
C)  365 days 
D)  180 days 
E)  78 days 
A)  730 days 
B)  414 days 
C)  365 days 
D)  180 days 
E)  78 days

Question 12

A catalyst accelerates a reaction because

Accepted Answer

A)  it increases the number of molecules with energy equal to or greater than the activation energy. 
B)  it lowers the activation energy for the reaction. 
C)  it increases the number of collisions between molecules. 
D)  it increases the temperature of the molecules in the reaction. 
E)  it supplies energy to reactant molecules. 
A)  it increases the number of molecules with energy equal to or greater than the activation energy. 
B)  it lowers the activation energy for the reaction. 
C)  it increases the number of collisions between molecules. 
D)  it increases the temperature of the molecules in the reaction. 
E)  it supplies energy to reactant molecules.

Question 13

A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

Accepted Answer

A)  [R] vs. 1/time 
B)  1/[R] vs. time 
C)  [R]2 vs. time 
D)  1/[R]2 vs. time 
E)  ln[R] vs. time 
A)  [R] vs. 1/time 
B)  1/[R] vs. time 
C)  [R]2 vs. time 
D)  1/[R]2 vs. time 
E)  ln[R] vs. time

Question 14

A reaction is first-order with respect to the reactant R. Which of the following plots will produce a straight line?

Accepted Answer

A)  [R] vs. 1/time 
B)  1/[R] vs. time 
C)  [R]2 vs. time 
D)  1/[R]2 vs. time 
E)  ln[R] vs. time 
A)  [R] vs. 1/time 
B)  1/[R] vs. time 
C)  [R]2 vs. time 
D)  1/[R]2 vs. time 
E)  ln[R] vs. time

Question 15

In order to obtain the activation energy of a reaction using a graphical method, __________ is plotted against _________, giving a straight line whose slope is equal to __________.

Accepted Answer

A)  k; T; -Ea 
B)  k; 1/T; -Ea 
C)  lnk; T; -Ea/R 
D)  k; 1/T; -Ea/R 
E)  lnk; 1/T; -Ea/R 
A)  k; T; -Ea 
B)  k; 1/T; -Ea 
C)  lnk; T; -Ea/R 
D)  k; 1/T; -Ea/R 
E)  lnk; 1/T; -Ea/R

Question 16

For the reaction 3A(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)200 0.100 6.00 × 10-2
2 0)100 0.100 1.50 × 10-2
3 0)200 0.200 1.20 × 10-1
4 0)300 0.200 2.70 × 10-1

Accepted Answer

A)  Rate = k[A][B] 
B)  Rate = k[A][B]2 
C)  Rate = k[A]3[B] 2 
D)  Rate = k[A]1.5[B] 
E)  Rate = k[A] 2[B] 
A)  Rate = k[A][B] 
B)  Rate = k[A][B]2 
C)  Rate = k[A]3[B] 2 
D)  Rate = k[A]1.5[B] 
E)  Rate = k[A] 2[B]

Question 17

Chlorine atoms act as heterogeneous catalysts in the destruction of ozone in the stratosphere.

Accepted Answer

A) True 
 B)False

Question 18

The units of the rate constant depend on the order of the reaction.

Accepted Answer

A) True 
 B)False

Consider the reaction 2NH₃(g) → N₂(g) + 3H₂(g) If the rate Δ[H₂]/Δt is 0.030 mol L_-1s_-1, then Δ[NH₃ ]/Δt is

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

In going from room temperature (25.0°C) to 10°C above room temperature, the rate of a reaction doubles. Calculate the activation energy for the reaction.

If the activation energy of a reaction decreases by 10.0 kJ/mol, from 100.0 to 90.0 kJ/mol, what effect will this have on the rate of reaction at 298K?

Consider the following reaction 8A(g) + 5B(g) → 8C(g) + 6D(g) If [C] is increasing at the rate of 4.0 mol L^-1s^-1, at what rate is [B] changing?

Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?

A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 × 10²⁰ molecules of reactant at time t = 0, how many molecules remain unreacted after 100.0 minutes?

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10^-4 mol L^-1 and the rate constant k = 1.08 × 10^-6 s^-1, what concentration of R remains after 25 days?

The active ingredient in an over the counter pain killer analgesic decomposes with a rate constant, k = 9.05 × 10^-4 day^-¹. How many days does it take for 15% of the original ingredient to decompose?

A catalyst accelerates a reaction because

A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

A reaction is first-order with respect to the reactant R. Which of the following plots will produce a straight line?

In order to obtain the activation energy of a reaction using a graphical method, ______ is plotted against _, giving a straight line whose slope is equal to ______.

Chlorine atoms act as heterogeneous catalysts in the destruction of ozone in the stratosphere.

The units of the rate constant depend on the order of the reaction.

Keys to Studying Chemistry Definitions, Units, and Problem Solving

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces Liquids, Solids, and Phase Changes

The Properties of Mixtures Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Equilibrium the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics Entropy, Free Energy, and Reaction Direction

Electrochemistry Chemical Change and Electrical Work

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Exam 16: Kinetics Rates and Mechanisms of Chemical Reactions

Consider the reaction 2NH3(g) → N2(g) + 3H2(g) If the rate Δ[H2]/Δt is 0.030 mol L-1s-1, then Δ[NH3 ]/Δt is

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

In going from room temperature (25.0°C) to 10°C above room temperature, the rate of a reaction doubles. Calculate the activation energy for the reaction.

If the activation energy of a reaction decreases by 10.0 kJ/mol, from 100.0 to 90.0 kJ/mol, what effect will this have on the rate of reaction at 298K?

Consider the following reaction 8A(g) + 5B(g) → 8C(g) + 6D(g) If [C] is increasing at the rate of 4.0 mol L-1s-1, at what rate is [B] changing?

Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?

A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 × 1020 molecules of reactant at time t = 0, how many molecules remain unreacted after 100.0 minutes?

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10-4 mol L-1 and the rate constant k = 1.08 × 10-6 s-1, what concentration of R remains after 25 days?

The active ingredient in an over the counter pain killer analgesic decomposes with a rate constant, k = 9.05 × 10-4 day-1. How many days does it take for 15% of the original ingredient to decompose?

A catalyst accelerates a reaction because

A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

A reaction is first-order with respect to the reactant R. Which of the following plots will produce a straight line?

In order to obtain the activation energy of a reaction using a graphical method, __________ is plotted against _________, giving a straight line whose slope is equal to __________.

Chlorine atoms act as heterogeneous catalysts in the destruction of ozone in the stratosphere.

The units of the rate constant depend on the order of the reaction.

Keys to Studying Chemistry Definitions, Units, and Problem Solving

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces Liquids, Solids, and Phase Changes

The Properties of Mixtures Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Equilibrium the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics Entropy, Free Energy, and Reaction Direction

Electrochemistry Chemical Change and Electrical Work

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Consider the reaction 2NH₃(g) → N₂(g) + 3H₂(g) If the rate Δ[H₂]/Δt is 0.030 mol L_-1s_-1, then Δ[NH₃ ]/Δt is

Consider the following reaction 8A(g) + 5B(g) → 8C(g) + 6D(g) If [C] is increasing at the rate of 4.0 mol L^-1s^-1, at what rate is [B] changing?

A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 × 10²⁰ molecules of reactant at time t = 0, how many molecules remain unreacted after 100.0 minutes?

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10^-4 mol L^-1 and the rate constant k = 1.08 × 10^-6 s^-1, what concentration of R remains after 25 days?

The active ingredient in an over the counter pain killer analgesic decomposes with a rate constant, k = 9.05 × 10^-4 day^-¹. How many days does it take for 15% of the original ingredient to decompose?

In order to obtain the activation energy of a reaction using a graphical method, ______ is plotted against _, giving a straight line whose slope is equal to ______.