Question 1

Consider the following reaction at equilibrium. What effect will reducing the volume of the reaction mixture have on the system? CuS(s) + O2(g) ⇌ Cu(s) + SO2(g)

Accepted Answer

A)  The equilibrium constant will decrease. 
B)  No effect will be observed. 
C)  The reaction will shift in the direction of products. 
D)  The equilibrium constant will increase. 
E)  The reaction will shift in the direction of reactants. 
A)  The equilibrium constant will decrease. 
B)  No effect will be observed. 
C)  The reaction will shift in the direction of products. 
D)  The equilibrium constant will increase. 
E)  The reaction will shift in the direction of reactants.

Question 2

An equilibrium mixture of CO, O2, and CO2 at a certain temperature contains 0.0010 mol L-1 CO2 and 0. 0015 mol L-1 O2. At this temperature, Kc equals 1.4 × 102 L mol-1 for the reaction: 2CO(g) + O2(g) ⇌ 2CO2(g)
What is the equilibrium concentration of CO?

Accepted Answer

A)  4.8 × 10-6 mol L-1 
B)  8.5 × 10-3 mol L-1 
C)  9.3 × 10-2 mol L-1 
D)  3.1 × 10-1 mol L-1 
A)  4.8 × 10-6 mol L-1 
B)  8.5 × 10-3 mol L-1 
C)  9.3 × 10-2 mol L-1 
D)  3.1 × 10-1 mol L-1

Question 3

Consider the following reaction at equilibrium. What effect will adding He gas have on the system? 2KClO3(s) ⇌ 2KCl(s) + 3O2(g)

Accepted Answer

A)  No effect will be observed since He is inert and is not included in the equilibrium expression. 
B)  The equilibrium constant will decrease. 
C)  The reaction will shift in the direction of reactants. 
D)  The equilibrium constant will increase. 
E)  The reaction will shift in the direction of products. 
A)  No effect will be observed since He is inert and is not included in the equilibrium expression. 
B)  The equilibrium constant will decrease. 
C)  The reaction will shift in the direction of reactants. 
D)  The equilibrium constant will increase. 
E)  The reaction will shift in the direction of products.

Question 4

Why is a thermodynamic equilibrium constant unitless?

Accepted Answer

Each concentration or pressure for a rea

Question 5

Express the equilibrium constant for the following reaction: CH3Cl(g) + 1/2 Cl2(g) ⇔ CH2Cl2(g) + 1/2 H2(g)

Accepted Answer

A)  KP =   
B)  KP =   
C)  KP =   
D)  KP =   
E)  KP =   
A)  KP =   
B)  KP =   
C)  KP =   
D)  KP =   
E)  KP =

Question 6

Which of the following statements is TRUE?

Accepted Answer

A)  Dynamic equilibrium occurs when the rate of the forward reaction equals the rate of the reverse reaction. 
B)  The equilibrium constant for the forward reaction is equal to the equilibrium constant for the reverse reaction. 
C)  A reaction quotient (Q) larger than the equilibrium constant (K) means that the reaction will favour the production of more products. 
D)  Dynamic equilibrium indicates that the amount of reactants and products are equal. 
E)  Dynamic equilibrium is established when K = 0. 
A)  Dynamic equilibrium occurs when the rate of the forward reaction equals the rate of the reverse reaction. 
B)  The equilibrium constant for the forward reaction is equal to the equilibrium constant for the reverse reaction. 
C)  A reaction quotient (Q) larger than the equilibrium constant (K) means that the reaction will favour the production of more products. 
D)  Dynamic equilibrium indicates that the amount of reactants and products are equal. 
E)  Dynamic equilibrium is established when K = 0.

Question 7

Consider the following reaction at equilibrium. What effect will removing NO2 have on the system? SO2(g) + NO2(g) ⇌ SO3(g) + NO(g)

Accepted Answer

A)  The reaction will shift in the direction of products. 
B)  The reaction will shift to decrease the pressure. 
C)  No change will occur since NO2 is not included in the equilibrium expression. 
D)  The reaction will shift in the direction of reactants. 
E)  The equilibrium constant will decrease. 
A)  The reaction will shift in the direction of products. 
B)  The reaction will shift to decrease the pressure. 
C)  No change will occur since NO2 is not included in the equilibrium expression. 
D)  The reaction will shift in the direction of reactants. 
E)  The equilibrium constant will decrease.

Question 8

Consider the following reaction and its equilibrium constant: SO2(g) + NO2(g) ⇌ SO3(g) + NO(g) Kc = 0.33
A reaction mixture contains 1.0 mol L-1 SO2, 2.0 mol L-1 NO2 , 0.66 mol L-1 SO3, and 1.0 mol L-1 NO. Which of the following statements is TRUE concerning this system?

Accepted Answer

A)  The reaction will shift in the direction of reactants. 
B)  The equilibrium constant will decrease. 
C)  The reaction will shift in the direction of products. 
D)  The reaction quotient will decrease. 
E)  The system is at equilibrium. 
A)  The reaction will shift in the direction of reactants. 
B)  The equilibrium constant will decrease. 
C)  The reaction will shift in the direction of products. 
D)  The reaction quotient will decrease. 
E)  The system is at equilibrium.

Question 9

Consider the following reaction at equilibrium. What effect will increasing the temperature have on the system? C3H8(g) + 5O2(g) ⇌ 3CO2(g) + 4H2O(l) ΔrH° = -2220 kJ

Accepted Answer

A)  The reaction will shift in the direction of products. 
B)  The reaction will shift in the direction of reactants. 
C)  The equilibrium constant will increase. 
D)  The equilibrium constant will decrease. 
E)  No effect will be observed. 
A)  The reaction will shift in the direction of products. 
B)  The reaction will shift in the direction of reactants. 
C)  The equilibrium constant will increase. 
D)  The equilibrium constant will decrease. 
E)  No effect will be observed.

Question 10

Calculate the value of [N2]eq if [H2]eq = 2.0 mol L-1, [NH3]eq = 0.50 mol L-1, and Kc = 2.0. N2(g) + 3H2(g) ⇌ 2NH3(g)

Accepted Answer

A)  0.016 mol L-1 
B)  0.031 mol L-1 
C)  0.062 mol L-1 
D)  0.40 mol L-1 
E)  62.5 mol L-1 
A)  0.016 mol L-1 
B)  0.031 mol L-1 
C)  0.062 mol L-1 
D)  0.40 mol L-1 
E)  62.5 mol L-1

Question 11

Consider the following reaction: Xe(g) + 2F2(g) ⇌ XeF4(g)
A reaction mixture initially contains 2.24 bar Xe and 4.27 bar F2. If the equilibrium pressure of Xe is 0.34 bar, find the equilibrium constant (Kp) for the reaction.

Accepted Answer

A)  25 bar-2 
B)  0.12 bar-2 
C)  0.99 bar-2 
D)  8.3 bar-2 
E)  0.040 bar-2 
A)  25 bar-2 
B)  0.12 bar-2 
C)  0.99 bar-2 
D)  8.3 bar-2 
E)  0.040 bar-2

Question 12

The equilibrium constant, Kp, equals 3.40 at 25 °C for the isomerization reaction: cis-2-butene ⇌ trans-2-butene
If a flask initially contains 5.00 bar of each gas, in what direction will the system shift to reach equilibrium?

Accepted Answer

A)  It will shift left. 
B)  It will shift right. 
C)  The system is already at equilibrium. 
D)  The system is not at equilibrium and will remain in an unequilibrated state. 
A)  It will shift left. 
B)  It will shift right. 
C)  The system is already at equilibrium. 
D)  The system is not at equilibrium and will remain in an unequilibrated state.

Question 13

For which reaction will Kp = Kc?

Accepted Answer

A)  S(s) + O2(g) ⇌ SO2(g) 
B)  2HgO(s) ⇌ Hg(l) + O2(g) 
C)  CaCO3(s) ⇌ CaO(s) + CO2(g) 
D)  H2CO3(s) ⇌ H2O(l) + CO2(g) 
E)  2H2O(l) ⇌ 2H2(g) + O2(g) 
A)  S(s) + O2(g) ⇌ SO2(g) 
B)  2HgO(s) ⇌ Hg(l) + O2(g) 
C)  CaCO3(s) ⇌ CaO(s) + CO2(g) 
D)  H2CO3(s) ⇌ H2O(l) + CO2(g) 
E)  2H2O(l) ⇌ 2H2(g) + O2(g)

Question 14

Express the equilibrium constant for the following reaction: P4(s) + 5O2(g) ⇌ P4O10(s)

Accepted Answer

A)  Kc =   
B)  Kc =   
C)  Kc = [O2]-5 
D)  Kc = [O2]5 
E)  Kc =   
A)  Kc =   
B)  Kc =   
C)  Kc = [O2]-5 
D)  Kc = [O2]5 
E)  Kc =

Question 15

In a reaction mixture containing only products, what is the value of Q?

Accepted Answer

A)  -1 
B)  1 
C)  ∞ 
D)  0 
E)  Q = K 
A)  -1 
B)  1 
C)  ∞ 
D)  0 
E)  Q = K

Question 16

What is the implication of Q > K?

Accepted Answer

A)  It means the reverse reaction will proceed to form more reactants. 
B)  It means the forward reaction will proceed to form more products. 
C)  It means the reaction is at equilibrium. 
D)  It means the reaction is shifted to the right. 
A)  It means the reverse reaction will proceed to form more reactants. 
B)  It means the forward reaction will proceed to form more products. 
C)  It means the reaction is at equilibrium. 
D)  It means the reaction is shifted to the right.

Question 17

The equilibrium constant is given for one of two reactions below. Determine the value of the missing equilibrium constant. 2HD(g) ⇌ H2(g) + D2(g) K = 0.28
2H2(g) + 2D2(g) ⇌ 4HD(g) K = ?

Accepted Answer

A)  7.8 × 10-2 
B)  3.6 
C)  0.53 
D)  13 
E)  1.9 
A)  7.8 × 10-2 
B)  3.6 
C)  0.53 
D)  13 
E)  1.9

Question 18

Can the Kp and Kc for a reaction ever have the same value? Why or why not?

Accepted Answer

Yes, they can have the same value. Since

Question 19

For which of the following reactions will ∆n = 2?

Accepted Answer

A)  H2(g) + I2(g) ⇌ 2HI(g) 
B)  CH4(g) + H2O(g) ⇌ CO(g) + 3H2(g) 
C)  N2O4(g) ⇌ 2NO2(g) 
D)  CO(g) + 2H2(g) ⇌ CH3OH(g) 
E)  N2(g) + 3H2(g) ⇌ 2NH3(g) 
A)  H2(g) + I2(g) ⇌ 2HI(g) 
B)  CH4(g) + H2O(g) ⇌ CO(g) + 3H2(g) 
C)  N2O4(g) ⇌ 2NO2(g) 
D)  CO(g) + 2H2(g) ⇌ CH3OH(g) 
E)  N2(g) + 3H2(g) ⇌ 2NH3(g)

Question 20

Why aren't solids or liquids included in an equilibrium expression?

Accepted Answer

The equilibrium constant relat

Exam 14: Chemical Equilibrium

Consider the following reaction at equilibrium. What effect will reducing the volume of the reaction mixture have on the system? CuS(s) + O2(g) ⇌ Cu(s) + SO2(g)

An equilibrium mixture of CO, O2, and CO2 at a certain temperature contains 0.0010 mol L-1 CO2 and 0. 0015 mol L-1 O2. At this temperature, Kc equals 1.4 × 102 L mol-1 for the reaction: 2CO(g) + O2(g) ⇌ 2CO2(g) What is the equilibrium concentration of CO?

Consider the following reaction at equilibrium. What effect will adding He gas have on the system? 2KClO3(s) ⇌ 2KCl(s) + 3O2(g)

Why is a thermodynamic equilibrium constant unitless?

Express the equilibrium constant for the following reaction: CH3Cl(g) + 1/2 Cl2(g) ⇔ CH2Cl2(g) + 1/2 H2(g)

Which of the following statements is TRUE?

Consider the following reaction at equilibrium. What effect will removing NO2 have on the system? SO2(g) + NO2(g) ⇌ SO3(g) + NO(g)

Consider the following reaction and its equilibrium constant: SO2(g) + NO2(g) ⇌ SO3(g) + NO(g) Kc = 0.33 A reaction mixture contains 1.0 mol L-1 SO2, 2.0 mol L-1 NO2 , 0.66 mol L-1 SO3, and 1.0 mol L-1 NO. Which of the following statements is TRUE concerning this system?

Consider the following reaction at equilibrium. What effect will increasing the temperature have on the system? C3H8(g) + 5O2(g) ⇌ 3CO2(g) + 4H2O(l) ΔrH° = -2220 kJ

Calculate the value of [N2]eq if [H2]eq = 2.0 mol L-1, [NH3]eq = 0.50 mol L-1, and Kc = 2.0. N2(g) + 3H2(g) ⇌ 2NH3(g)

Consider the following reaction: Xe(g) + 2F2(g) ⇌ XeF4(g) A reaction mixture initially contains 2.24 bar Xe and 4.27 bar F2. If the equilibrium pressure of Xe is 0.34 bar, find the equilibrium constant (Kp) for the reaction.

The equilibrium constant, Kp, equals 3.40 at 25 °C for the isomerization reaction: cis-2-butene ⇌ trans-2-butene If a flask initially contains 5.00 bar of each gas, in what direction will the system shift to reach equilibrium?

For which reaction will Kp = Kc?

Express the equilibrium constant for the following reaction: P4(s) + 5O2(g) ⇌ P4O10(s)

In a reaction mixture containing only products, what is the value of Q?

What is the implication of Q > K?

The equilibrium constant is given for one of two reactions below. Determine the value of the missing equilibrium constant. 2HD(g) ⇌ H2(g) + D2(g) K = 0.28 2H2(g) + 2D2(g) ⇌ 4HD(g) K = ?

Can the Kp and Kc for a reaction ever have the same value? Why or why not?

For which of the following reactions will ∆n = 2?

Why aren't solids or liquids included in an equilibrium expression?

Units of Measurement for Physical and Chemical Change

Atoms and Elements

Molecules, Compounds, and Nomenclature

Chemical Reactions and Stoichiometry

Gases

Thermochemistry

The Quantum-Mechanical Model of the Atom

Periodic Properties of the Elements

Chemical Bonding I: Lewis Theory

Chemical Bonding Ii: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory

Liquids, Solids, and Intermolecular Forces

Solutions

Chemical Kinetics

Acids and Bases

Aqueous Ionic Equilibrium

Gibbs Energy and Thermodynamics

Electrochemistry

Radioactivity and Nuclear Chemistry

Organic Chemistry I: Structures

Organic Chemistry Ii: Reactions

Biochemistry

Chemistry of the Nonmetals

Metals and Metallurgy

Transition Metals and Coordination Compounds

Filters

Consider the following reaction at equilibrium. What effect will reducing the volume of the reaction mixture have on the system? CuS(s) + O₂(g) ⇌ Cu(s) + SO₂(g)

An equilibrium mixture of CO, O₂, and CO₂ at a certain temperature contains 0.0010 mol L^-1 CO₂ and 0. 0015 mol L^-1 O₂. At this temperature, K_c equals 1.4 × 10² L mol^-1 for the reaction: 2CO(g) + O₂(g) ⇌ 2CO₂(g) What is the equilibrium concentration of CO?

Consider the following reaction at equilibrium. What effect will adding He gas have on the system? 2KClO₃(s) ⇌ 2KCl(s) + 3O₂(g)

Express the equilibrium constant for the following reaction: CH₃Cl(g) + 1/2 Cl₂(g) ⇔ CH₂Cl₂(g) + 1/2 H₂(g)

Consider the following reaction at equilibrium. What effect will removing NO₂ have on the system? SO₂(g) + NO₂(g) ⇌ SO₃(g) + NO(g)

Consider the following reaction and its equilibrium constant: SO₂(g) + NO₂(g) ⇌ SO₃(g) + NO(g) K_c = 0.33 A reaction mixture contains 1.0 mol L^-1 SO₂, 2.0 mol L^-1 NO₂, 0.66 mol L^-1 SO₃, and 1.0 mol L^-1 NO. Which of the following statements is TRUE concerning this system?

Consider the following reaction at equilibrium. What effect will increasing the temperature have on the system? C₃H₈(g) + 5O₂(g) ⇌ 3CO₂(g) + 4H₂O(l) Δ_rH° = -2220 kJ

Calculate the value of [N₂]_eq if [H₂]_eq = 2.0 mol L^-1, [NH₃]_eq= 0.50 mol L^-1, and K_c = 2.0. N₂(g) + 3H₂(g) ⇌ 2NH₃(g)

Consider the following reaction: Xe(g) + 2F₂(g) ⇌ XeF₄(g) A reaction mixture initially contains 2.24 bar Xe and 4.27 bar F₂. If the equilibrium pressure of Xe is 0.34 bar, find the equilibrium constant (K_p) for the reaction.

The equilibrium constant, K_p, equals 3.40 at 25 °C for the isomerization reaction: cis-2-butene ⇌ trans-2-butene If a flask initially contains 5.00 bar of each gas, in what direction will the system shift to reach equilibrium?

For which reaction will K_p = K_c?

Express the equilibrium constant for the following reaction: P₄(s) + 5O₂(g) ⇌ P₄O₁₀(s)

The equilibrium constant is given for one of two reactions below. Determine the value of the missing equilibrium constant. 2HD(g) ⇌ H₂(g) + D₂(g) K = 0.28 2H₂(g) + 2D₂(g) ⇌ 4HD(g) K = ?

Can the K_p and K_c for a reaction ever have the same value? Why or why not?