Question 1

Le Châtelier's principle states that if a system at equilibrium is disturbed, the equilibrium will shift to minimize the disturbance.

Accepted Answer

A) True 
 B)False  True

Question 2

Dinitrogen tetroxide partially decomposes according to the following equilibrium: N2O4 (g)   2NO2 (g)
A 1.000-L flask is charged with 3.00 × 10-2 mol of N2O4. At equilibrium, 2.36 × 10-2 mol of N2O4 remains. Keq for this reaction is __________.

Accepted Answer

A) 0.723 
B) 0.391 
C) 0.212 
D) 6.94 × 10-3 
E) 1.92 × 10-4 
A) 0.723 
B) 0.391 
C) 0.212 
D) 6.94 × 10-3 
E) 1.92 × 10-4 D

Question 3

Which one of the following is true concerning the Haber process?

Accepted Answer

A) It is a process used for shifting equilibrium positions to the right for more economical chemical synthesis of a variety of substances. 
B) It is a process used for the synthesis of ammonia. 
C) It is another way of stating Le Châtelier's principle. 
D) It is an industrial synthesis of sodium chloride that was discovered by Karl Haber. 
E) It is a process for the synthesis of elemental chlorine. 
A) It is a process used for shifting equilibrium positions to the right for more economical chemical synthesis of a variety of substances. 
B) It is a process used for the synthesis of ammonia. 
C) It is another way of stating Le Châtelier's principle. 
D) It is an industrial synthesis of sodium chloride that was discovered by Karl Haber. 
E) It is a process for the synthesis of elemental chlorine. B

Question 4

The equilibrium constant for the gas phase reaction 2NH3 (g)   N2 (g)+ 3H2 (g)
Is Keq = 230 at 300°C. At equilibrium, __________.

Accepted Answer

A) products predominate 
B) reactants predominate 
C) roughly equal amounts of products and reactants are present 
D) only products are present 
E) only reactants are present 
A) products predominate 
B) reactants predominate 
C) roughly equal amounts of products and reactants are present 
D) only products are present 
E) only reactants are present

Question 5

Which of the following expressions is the correct equilibrium-constant expression for the reaction below? HF (aq)+ H2O (l)   H3O+ (aq)+ F- (aq)

Accepted Answer

A) [HF][H2O] / [H3O+][F-] 
B) 1 / [HF] 
C) [H3O+][F-] / [HF][H2O] 
D) [H3O+][F-] / [HF] 
E) [F-] / [HF] 
A) [HF][H2O] / [H3O+][F-] 
B) 1 / [HF] 
C) [H3O+][F-] / [HF][H2O] 
D) [H3O+][F-] / [HF] 
E) [F-] / [HF]

Question 6

If Reaction A + Reaction B = Reaction C, then Kc Reaction C = __________.

Accepted Answer

K_cReaction

Question 7

The equilibrium-constant expression for the reaction Ti (s)+ 2Cl2 (g)   TiCl4 (l)
Is given by

Accepted Answer

A)    
B)    
C)    
D) [Cl2 (g)]-2  
E)    
A)    
B)    
C)    
D) [Cl2 (g)]-2  
E)

Question 8

The Keq for the equilibrium below is 0.112 at 700.0°C. SO2 (g)+   O2 (g)   SO3 (g)
What is the value of Keq at this temperature for the following reaction?
2SO3 (g)   2SO2 (g)+ O2 (g)

Accepted Answer

A) 79.7 
B) 2.99 
C) 17.86 
D) 4.46 
E) 8.93 
A) 79.7 
B) 2.99 
C) 17.86 
D) 4.46 
E) 8.93

Question 9

Given the following reaction at equilibrium, if Kc = 1.90 × 1019 at 25.0°C, Kp = __________. H2 (g)+ Br2 (g)   2 HBr (g)

Accepted Answer

A) 5.26 × 10-20 
B) 1.56 × 104 
C) 6.44 × 105 
D) 1.90 × 1019 
E) none of the above 
A) 5.26 × 10-20 
B) 1.56 × 104 
C) 6.44 × 105 
D) 1.90 × 1019 
E) none of the above

Question 10

For an exothermic reaction, increasing the reaction temperature results in a(an)__________ in K.

Accepted Answer

The answer of For an exothermic reaction, increasing the reaction...

Question 11

The Keq for the equilibrium below is 0.112 at 700.0°C. SO2 (g)+   O2 (g)   SO3 (g)
What is the value of Keq at this temperature for the following reaction?
SO3 (g)   SO2 (g)+   O2 (g)

Accepted Answer

A) 0.224 
B) 0.0125 
C) 0.112 
D) 8.93 
E) -0.112 
A) 0.224 
B) 0.0125 
C) 0.112 
D) 8.93 
E) -0.112

Question 12

The equilibrium constant (Kp)for the interconversion of PCl5 and PCl3 is 0.0121: PCl5 (g)   PCl3 (g)+ Cl2 (g)
A vessel is charged with PCl5, giving an initial pressure of 0.123 atm. At equilibrium, the partial pressure of PCl3 is __________ atm.

Accepted Answer

A) 0.0782 
B) 0.0455 
C) 0.0908 
D) 0.0330 
E) 0.123 
A) 0.0782 
B) 0.0455 
C) 0.0908 
D) 0.0330 
E) 0.123

Question 13

At 27°C, Kp = 0.095 for the equilibrium: NH4HS (s)   NH3 (g)+ H2S (g)
A sample of solid NH4HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm)of ammonia, assuming that some solid NH4HS remains.

Accepted Answer

A) 0.31 
B) 0.095 
C) 0.052 
D) 0.0049 
E) 3.8 
A) 0.31 
B) 0.095 
C) 0.052 
D) 0.0049 
E) 3.8

Question 14

The reaction below is exothermic: 2SO2 (g)+ O2 (g)   2SO3 (g)
Le Châtelier's Principle predicts that __________ will result in an increase in the number of moles of SO3 (g)in the reaction container.

Accepted Answer

A) increasing the pressure 
B) decreasing the pressure 
C) increasing the temperature 
D) removing some oxygen 
E) increasing the volume of the container 
A) increasing the pressure 
B) decreasing the pressure 
C) increasing the temperature 
D) removing some oxygen 
E) increasing the volume of the container

Question 15

Consider the following reaction at equilibrium: 2SO2 (g)+ O2 (g)   2SO3 (g)ΔH° = -99 kJ
Le Châtelier's principle predicts that an increase in temperature will result in __________.

Accepted Answer

A) a decrease in the partial pressure of SO3 
B) a decrease in the partial pressure of SO2 
C) an increase in Keq 
D) no changes in equilibrium partial pressures 
E) the partial pressure of O2 will decrease 
A) a decrease in the partial pressure of SO3 
B) a decrease in the partial pressure of SO2 
C) an increase in Keq 
D) no changes in equilibrium partial pressures 
E) the partial pressure of O2 will decrease

Question 16

In an exothermic equilibrium reaction, increasing the reaction temperature favors the formation of reactants.

Accepted Answer

A) True 
 B)False

Question 17

Nitrosyl bromide decomposes according to the following equation. 2NOBr (g)   2NO (g)+ Br2 (g)
A sample of NOBr (0.64 mol)was placed in a 1.00-L flask containing no NO or Br2. At equilibrium the flask contained 0.36 mol of NOBr. How many moles of NO and Br2, respectively, are in the flask at equilibrium?

Accepted Answer

A) .28,.28 
B) .36,.18 
C) .28,.14 
D) .14,.23 
E) .36,.36 
A) .28,.28 
B) .36,.18 
C) .28,.14 
D) .14,.23 
E) .36,.36

Question 18

Given the following reaction at equilibrium at 450.0°C: CaCO3 (s)   CaO (s)+ CO2 (g)
If pCO2 = 0.0135 atm, Kc = __________.

Accepted Answer

A) 135 
B) 0.0821 
C) 0.801 
D) 2.27 × 10-4 
E) 8.01 
A) 135 
B) 0.0821 
C) 0.801 
D) 2.27 × 10-4 
E) 8.01

Question 19

Consider the following reaction at equilibrium: 2CO2 (g)   2CO (g)+ O2 (g)ΔH° = -514 kJ
Le Châtelier's principle predicts that adding O2 (g)to the reaction container will __________.

Accepted Answer

A) increase the partial pressure of CO (g)at equilibrium 
B) decrease the partial pressure of CO2 (g)at equilibrium 
C) increase the value of the equilibrium constant 
D) increase the partial pressure of CO2 (g)at equilibrium 
E) decrease the value of the equilibrium constant 
A) increase the partial pressure of CO (g)at equilibrium 
B) decrease the partial pressure of CO2 (g)at equilibrium 
C) increase the value of the equilibrium constant 
D) increase the partial pressure of CO2 (g)at equilibrium 
E) decrease the value of the equilibrium constant

Question 20

If a reaction is endothermic, __________ the reaction temperature results in an increase in K.

Accepted Answer

The answer of If a reaction is endothermic, __________ the...

Exam 15: Chemical Equilibrium

Le Châtelier's principle states that if a system at equilibrium is disturbed, the equilibrium will shift to minimize the disturbance.

Dinitrogen tetroxide partially decomposes according to the following equilibrium: N2O4 (g) 2NO2 (g) A 1.000-L flask is charged with 3.00 × 10-2 mol of N2O4. At equilibrium, 2.36 × 10-2 mol of N2O4 remains. Keq for this reaction is __________.

Which one of the following is true concerning the Haber process?

The equilibrium constant for the gas phase reaction 2NH3 (g) N2 (g)+ 3H2 (g) Is Keq = 230 at 300°C. At equilibrium, __________.

Which of the following expressions is the correct equilibrium-constant expression for the reaction below? HF (aq)+ H2O (l) H3O+ (aq)+ F- (aq)

If Reaction A + Reaction B = Reaction C, then Kc Reaction C = __________.

The equilibrium-constant expression for the reaction Ti (s)+ 2Cl2 (g) TiCl4 (l) Is given by

The Keq for the equilibrium below is 0.112 at 700.0°C. SO2 (g)+ O2 (g) SO3 (g) What is the value of Keq at this temperature for the following reaction? 2SO3 (g) 2SO2 (g)+ O2 (g)

Given the following reaction at equilibrium, if Kc = 1.90 × 1019 at 25.0°C, Kp = __________. H2 (g)+ Br2 (g) 2 HBr (g)

For an exothermic reaction, increasing the reaction temperature results in a(an)__________ in K.

The Keq for the equilibrium below is 0.112 at 700.0°C. SO2 (g)+ O2 (g) SO3 (g) What is the value of Keq at this temperature for the following reaction? SO3 (g) SO2 (g)+ O2 (g)

The equilibrium constant (Kp)for the interconversion of PCl5 and PCl3 is 0.0121: PCl5 (g) PCl3 (g)+ Cl2 (g) A vessel is charged with PCl5, giving an initial pressure of 0.123 atm. At equilibrium, the partial pressure of PCl3 is __________ atm.

At 27°C, Kp = 0.095 for the equilibrium: NH4HS (s) NH3 (g)+ H2S (g) A sample of solid NH4HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm)of ammonia, assuming that some solid NH4HS remains.

The reaction below is exothermic: 2SO2 (g)+ O2 (g) 2SO3 (g) Le Châtelier's Principle predicts that __________ will result in an increase in the number of moles of SO3 (g)in the reaction container.

Consider the following reaction at equilibrium: 2SO2 (g)+ O2 (g) 2SO3 (g)ΔH° = -99 kJ Le Châtelier's principle predicts that an increase in temperature will result in __________.

In an exothermic equilibrium reaction, increasing the reaction temperature favors the formation of reactants.

Given the following reaction at equilibrium at 450.0°C: CaCO3 (s) CaO (s)+ CO2 (g) If pCO2 = 0.0135 atm, Kc = __________.

Consider the following reaction at equilibrium: 2CO2 (g) 2CO (g)+ O2 (g)ΔH° = -514 kJ Le Châtelier's principle predicts that adding O2 (g)to the reaction container will __________.

If a reaction is endothermic, __________ the reaction temperature results in an increase in K.

Introduction: Matter and Measurement

Atoms, Molecules, and Ions

Stoichiometry: Calculations With Chemical Formulas and Equations

Aqueous Reactions and Solution Stoichiometry

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Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Gases

Liquids and Intermolecular Forces

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Properties of Solutions

Chemical Kinetics

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

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Dinitrogen tetroxide partially decomposes according to the following equilibrium: N₂O₄ (g) 2NO₂ (g) A 1.000-L flask is charged with 3.00 × 10^-2 mol of N₂O₄. At equilibrium, 2.36 × 10^-2 mol of N₂O₄ remains. K_eq for this reaction is __________.

The equilibrium constant for the gas phase reaction 2NH₃ (g) N₂ (g)+ 3H₂ (g) Is K_eq = 230 at 300°C. At equilibrium, __________.

Which of the following expressions is the correct equilibrium-constant expression for the reaction below? HF (aq)+ H₂O (l) H₃O⁺ (aq)+ F^- (aq)

If Reaction A + Reaction B = Reaction C, then K_cReaction C = __________.

The equilibrium-constant expression for the reaction Ti (s)+ 2Cl₂(g) TiCl₄(l) Is given by

The K_eq for the equilibrium below is 0.112 at 700.0°C. SO₂ (g)+ O₂(g) SO₃ (g) What is the value of K_eq at this temperature for the following reaction? 2SO₃ (g) 2SO₂ (g)+ O₂ (g)

Given the following reaction at equilibrium, if K_c = 1.90 × 10¹⁹at 25.0°C, K_p = __________. H₂ (g)+ Br₂ (g) 2 HBr (g)

The K_eq for the equilibrium below is 0.112 at 700.0°C. SO₂ (g)+ O₂ (g) SO₃ (g) What is the value of K_eq at this temperature for the following reaction? SO₃ (g) SO₂ (g)+ O₂ (g)

The equilibrium constant (K_p)for the interconversion of PCl₅ and PCl₃ is 0.0121: PCl₅ (g) PCl₃ (g)+ Cl₂ (g) A vessel is charged with PCl₅, giving an initial pressure of 0.123 atm. At equilibrium, the partial pressure of PCl₃ is __________ atm.

At 27°C, K_p = 0.095 for the equilibrium: NH₄HS (s) NH₃(g)+ H₂S (g) A sample of solid NH₄HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm)of ammonia, assuming that some solid NH₄HS remains.

The reaction below is exothermic: 2SO₂ (g)+ O₂ (g) 2SO₃ (g) Le Châtelier's Principle predicts that __________ will result in an increase in the number of moles of SO₃ (g)in the reaction container.

Consider the following reaction at equilibrium: 2SO₂ (g)+ O₂ (g) 2SO₃ (g)ΔH° = -99 kJ Le Châtelier's principle predicts that an increase in temperature will result in __________.

Given the following reaction at equilibrium at 450.0°C: CaCO₃ (s) CaO (s)+ CO₂ (g) If pCO₂ = 0.0135 atm, K_c = __________.

Consider the following reaction at equilibrium: 2CO₂ (g) 2CO (g)+ O₂ (g)ΔH° = -514 kJ Le Châtelier's principle predicts that adding O₂ (g)to the reaction container will __________.