Question 1

For a reaction, the reaction quotient, Qc > Kc, the reaction ________.

Accepted Answer

A)  is at equilibrium 
B)  is exothermic 
C)  shifts to the right 
D)  shifts to the left 
E)  is endothermic 
A)  is at equilibrium 
B)  is exothermic 
C)  shifts to the right 
D)  shifts to the left 
E)  is endothermic D

Question 2

The value of the equilibrium constant for a given reaction depends on the initial concentrations of reactants.

Accepted Answer

A) True 
 B)False  False

Question 3

Consider the following hypothetical equilibrium reaction: A2(g) + B2(g) ⇌ 2AB(g) where Kc =   The equilibrium constant for the reaction: 2 A2(g) + 2 B2(g) ⇔ 4 AB(g) is ________.

Accepted Answer

A)    
B)  Kc4 
C)    
D)    
E)  Kc2 
A)    
B)  Kc4 
C)    
D)    
E)  Kc2 E

Question 4

Consider the following reversible reaction: POCl3(g) ⇌ POCl(g) + Cl2(g) Kc = 0.450
The following initial amounts of reactants and products were mixed: [POCl3] = 0.750 M, [POCl] = 0.550 M, and [Cl2] = 0.150 M. What is the equilibrium concentration of POCl?

Accepted Answer

A)  0.395 M 
B)  0.155 M 
C)  0.740 M 
D)  0.945 M 
E)  0.360 M 
A)  0.395 M 
B)  0.155 M 
C)  0.740 M 
D)  0.945 M 
E)  0.360 M

Question 5

For the reaction: PCl3(g) + Cl2(g) ⇌ PCl5(g) at 85°C, Kp = 1.19
If one starts with 2.00 atm pressure of PCl3, 1.00 atm pressure of Cl2 and no PCl5, what is the partial pressure of PCl5(g) at equilibrium?

Accepted Answer

A)  0.167 atm 
B)  0.739 atm 
C)  0.621 atm 
D)  0.465 atm 
E)  0.553 atm 
A)  0.167 atm 
B)  0.739 atm 
C)  0.621 atm 
D)  0.465 atm 
E)  0.553 atm

Question 6

Which of the following equilibrium constants-reaction type is INCORRECT?

Accepted Answer

A)  1.4 × 1083 goes to completion. 
B)  1.6 × 10-23 does not occur. 
C)  1.8 × 10-5 equilibrium reaction more reactants than products at equilibrium. 
D)  1.0 equilibrium reaction-equal amounts of products and reactants. 
E)  3.2 × 103 equilibrium reaction-more reactants than products at equilibrium. 
A)  1.4 × 1083 goes to completion. 
B)  1.6 × 10-23 does not occur. 
C)  1.8 × 10-5 equilibrium reaction more reactants than products at equilibrium. 
D)  1.0 equilibrium reaction-equal amounts of products and reactants. 
E)  3.2 × 103 equilibrium reaction-more reactants than products at equilibrium.

Question 7

Reaction quotient Q will always be equal to the reaction's equilibrium constant K.

Accepted Answer

A) True 
 B)False

Question 8

In a system in equilibrium, two opposing reactions occur at equal rates.

Accepted Answer

A) True 
 B)False

Question 9

Find Kp for the following reaction at 25.0°C. SbCl5(g) ⇌ SbCl3(g) + Cl2(g) Kc = 2.51 × 10-2

Accepted Answer

A)  0.614 
B)  1.03 × 10-3 
C)  5.15 × 10-2 
D)  9.74 × 102 
E)  39.8 
A)  0.614 
B)  1.03 × 10-3 
C)  5.15 × 10-2 
D)  9.74 × 102 
E)  39.8

Question 10

Consider the exothermic reaction: 4 HCl(aq) + MnO2(s) ⇌ Cl2(g) + 2 H2O(l) + MnCl2(aq)
The equilibrium is displaced to the left if:

Accepted Answer

A)  catalyst is added 
B)  pressure is lowered 
C)  temperature is lowered 
D)  H2O(l) is added 
E)  MnO2 (s) is added 
A)  catalyst is added 
B)  pressure is lowered 
C)  temperature is lowered 
D)  H2O(l) is added 
E)  MnO2 (s) is added

Question 11

A mixture containing 0.392 M A(g) and 0.452 M B(g) is allowed to come to equilibrium at 300 K. The reaction 3 A(g) + 2 B(g) ⇌ C(g) + D(g) occurs. At equilibrium, [C] = 0.00128 M. What is the value of Kc?

Accepted Answer

A)  7.35 × 10-3 
B)  1.39 × 10-4 
C)  1.36 × 102 
D)  9.24 × 10-6 
E)  7.19 × 106 
A)  7.35 × 10-3 
B)  1.39 × 10-4 
C)  1.36 × 102 
D)  9.24 × 10-6 
E)  7.19 × 106

Question 12

Consider the equilibrium system: N2O4(g) ⇌ 2 NO2(g) for which Kp = 0.1134 at 25°C and ΔH°rxn = 58.03 kJ/mol. Assume that 1 mole of N2O4 and 2 moles of NO2 are introduced into a 5.0 liter container. What will be the equilibrium value of [N2O4]?

Accepted Answer

A)  0.928 M 
B)  0.0822 M 
C)  0.358 M 
D)  0.379 M 
E)  0.042 M 
A)  0.928 M 
B)  0.0822 M 
C)  0.358 M 
D)  0.379 M 
E)  0.042 M

Question 13

Large value for equilibrium constant K means the reaction will be less complete at the equilibrium point.

Accepted Answer

A) True 
 B)False

Question 14

For 2 NO2(g) ⇌ N2O4(g), Kc = [N2O4]/[NO2]2. At equilibrium there are 0.0270 mol N2O4 and 0.450 mol NO2 in a 50.0-L container. What is Kc?

Accepted Answer

A)  0.00267 
B)  6.81 
C)  6.67 
D)  0.133 
E)  2.45 
A)  0.00267 
B)  6.81 
C)  6.67 
D)  0.133 
E)  2.45

Question 15

For the reaction 2 NO(g)⇌ N2O4(g) Kp equals ________.

Accepted Answer

A)  Kc 
B)  RT/Kc 
C)  Kc(RT) 
D)  Kc/RT 
E)  Kc(RT)2 
A)  Kc 
B)  RT/Kc 
C)  Kc(RT) 
D)  Kc/RT 
E)  Kc(RT)2

Question 16

0.75 mol of N2 and 1.20 mol of H2 are placed in a 3.0 liter container. When the reaction N2(g) + 3H2(g) ⇌ 2 NH3(g) reaches equilibrium, [H2] = 0.100 M. Which of the following is true?

Accepted Answer

A)  [NH3] = 0.150 M 
B)  [NH3] = 0.200 
C)  [N2] = 0.650 M 
D)  [N2] = 0.250 
E)  [NH3] = [H2] = 0.05 M 
A)  [NH3] = 0.150 M 
B)  [NH3] = 0.200 
C)  [N2] = 0.650 M 
D)  [N2] = 0.250 
E)  [NH3] = [H2] = 0.05 M

Question 17

For the reaction: 3 Fe(s) + 4 H2O(g) ⇌ Fe3O4(s) + 4 H2(g) what is the effect on equilibrium of increasing temperature of an exothermic reaction?

Accepted Answer

A)  The reaction shifts to the right. 
B)  There is no change. 
C)  The reaction shifts to the left. 
D)  The Kp is decreased. 
E)  The Kp is doubled. 
A)  The reaction shifts to the right. 
B)  There is no change. 
C)  The reaction shifts to the left. 
D)  The Kp is decreased. 
E)  The Kp is doubled.

Question 18

One method to aid in working equilibrium problems is the ICE table.

Accepted Answer

A) True 
 B)False

Question 19

The concentration of a pure solid is left out of a equilibrium constant expression but a pure liquid is included.

Accepted Answer

A) True 
 B)False

Question 20

For the decomposition of SO3(g), Kc = [SO2]2[O2]/[SO3]2, at equilibrium, there are 0.090 mol SO2, 0.110 mol O2, 0.100 mol SO3 in a 25.0-L container. What is the value of Kc?

Accepted Answer

A)  3.6 × 10-3 
B)  0.040 
C)  2.23 
D)  0.089 
E)  7.89 
A)  3.6 × 10-3 
B)  0.040 
C)  2.23 
D)  0.089 
E)  7.89

Exam 15: Principles of Chemical Equilibrium

For a reaction, the reaction quotient, Qc > Kc, the reaction ________.

The value of the equilibrium constant for a given reaction depends on the initial concentrations of reactants.

Consider the following hypothetical equilibrium reaction: A2(g) + B2(g) ⇌ 2AB(g) where Kc = The equilibrium constant for the reaction: 2 A2(g) + 2 B2(g) ⇔ 4 AB(g) is ________.

Consider the following reversible reaction: POCl3(g) ⇌ POCl(g) + Cl2(g) Kc = 0.450 The following initial amounts of reactants and products were mixed: [POCl3] = 0.750 M, [POCl] = 0.550 M, and [Cl2] = 0.150 M. What is the equilibrium concentration of POCl?

For the reaction: PCl3(g) + Cl2(g) ⇌ PCl5(g) at 85°C, Kp = 1.19 If one starts with 2.00 atm pressure of PCl3, 1.00 atm pressure of Cl2 and no PCl5, what is the partial pressure of PCl5(g) at equilibrium?

Which of the following equilibrium constants-reaction type is INCORRECT?

Reaction quotient Q will always be equal to the reaction's equilibrium constant K.

In a system in equilibrium, two opposing reactions occur at equal rates.

Find Kp for the following reaction at 25.0°C. SbCl5(g) ⇌ SbCl3(g) + Cl2(g) Kc = 2.51 × 10-2

Consider the exothermic reaction: 4 HCl(aq) + MnO2(s) ⇌ Cl2(g) + 2 H2O(l) + MnCl2(aq) The equilibrium is displaced to the left if:

A mixture containing 0.392 M A(g) and 0.452 M B(g) is allowed to come to equilibrium at 300 K. The reaction 3 A(g) + 2 B(g) ⇌ C(g) + D(g) occurs. At equilibrium, [C] = 0.00128 M. What is the value of Kc?

Consider the equilibrium system: N2O4(g) ⇌ 2 NO2(g) for which Kp = 0.1134 at 25°C and ΔH°rxn = 58.03 kJ/mol. Assume that 1 mole of N2O4 and 2 moles of NO2 are introduced into a 5.0 liter container. What will be the equilibrium value of [N2O4]?

Large value for equilibrium constant K means the reaction will be less complete at the equilibrium point.

For 2 NO2(g) ⇌ N2O4(g), Kc = [N2O4]/[NO2]2. At equilibrium there are 0.0270 mol N2O4 and 0.450 mol NO2 in a 50.0-L container. What is Kc?

For the reaction 2 NO(g)⇌ N2O4(g) Kp equals ________.

0.75 mol of N2 and 1.20 mol of H2 are placed in a 3.0 liter container. When the reaction N2(g) + 3H2(g) ⇌ 2 NH3(g) reaches equilibrium, [H2] = 0.100 M. Which of the following is true?

For the reaction: 3 Fe(s) + 4 H2O(g) ⇌ Fe3O4(s) + 4 H2(g) what is the effect on equilibrium of increasing temperature of an exothermic reaction?

One method to aid in working equilibrium problems is the ICE table.

The concentration of a pure solid is left out of a equilibrium constant expression but a pure liquid is included.

For the decomposition of SO3(g), Kc = [SO2]2[O2]/[SO3]2, at equilibrium, there are 0.090 mol SO2, 0.110 mol O2, 0.100 mol SO3 in a 25.0-L container. What is the value of Kc?

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

Chemical Kinetics

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

Filters

Consider the following hypothetical equilibrium reaction: A₂(g) + B₂(g) ⇌ 2AB(g) where Kc = The equilibrium constant for the reaction: 2 A₂(g) + 2 B₂(g) ⇔ 4 AB(g) is ________.

Consider the following reversible reaction: POCl₃(g) ⇌ POCl(g) + Cl₂(g) Kc = 0.450 The following initial amounts of reactants and products were mixed: [POCl₃] = 0.750 M, [POCl] = 0.550 M, and [Cl₂] = 0.150 M. What is the equilibrium concentration of POCl?

For the reaction: PCl₃(g) + Cl₂(g) ⇌ PCl₅(g) at 85°C, Kp = 1.19 If one starts with 2.00 atm pressure of PCl₃, 1.00 atm pressure of Cl₂ and no PCl₅, what is the partial pressure of PCl₅(g) at equilibrium?

Find Kp for the following reaction at 25.0°C. SbCl₅(g) ⇌ SbCl₃(g) + Cl₂(g) Kc = 2.51 × 10^-2

Consider the exothermic reaction: 4 HCl(aq) + MnO₂(s) ⇌ Cl₂(g) + 2 H₂O(l) + MnCl₂(aq) The equilibrium is displaced to the left if:

Consider the equilibrium system: N₂O₄(g) ⇌ 2 NO₂(g) for which Kp = 0.1134 at 25°C and ΔH°rxn = 58.03 kJ/mol. Assume that 1 mole of N₂O₄ and 2 moles of NO₂ are introduced into a 5.0 liter container. What will be the equilibrium value of [N₂O₄]?

For 2 NO₂(g) ⇌ N₂O₄(g), Kc = [N₂O₄]/[NO₂]₂. At equilibrium there are 0.0270 mol N₂O₄ and 0.450 mol NO₂in a 50.0-L container. What is Kc?

For the reaction 2 NO(g)⇌ N₂O₄(g) Kp equals ________.

0.75 mol of N₂ and 1.20 mol of H₂ are placed in a 3.0 liter container. When the reaction N₂(g) + 3H₂(g) ⇌ 2 NH₃(g) reaches equilibrium, [H₂] = 0.100 M. Which of the following is true?

For the reaction: 3 Fe(s) + 4 H₂O(g) ⇌ Fe₃O₄(s) + 4 H₂(g) what is the effect on equilibrium of increasing temperature of an exothermic reaction?

For the decomposition of SO₃(g), Kc = [SO₂]₂[O₂]/[SO₃]₂, at equilibrium, there are 0.090 mol SO₂, 0.110 mol O₂, 0.100 mol SO₃ in a 25.0-L container. What is the value of Kc?