Question 1

Determine the equilibrium constant for the following reaction at 498 K. 2 Hg(g)+ O2(g)→ 2 HgO(s)ΔH° = -304.2 kJ; ΔS° = -414.2 J/K

Accepted Answer

A)  1.87 × 1010 
B)  8.10 × 1031 
C)  2.31 × 10-22 
D)  5.34 × 10-11 
E)  4.33 × 1021 
A)  1.87 × 1010 
B)  8.10 × 1031 
C)  2.31 × 10-22 
D)  5.34 × 10-11 
E)  4.33 × 1021

Question 2

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ?
ΔH°f (kJ/mol)-133.9 50.6 -285.8
S°(J/mol∙K)266.9 121.2 191.6 70.0

Accepted Answer

A)  +4.90 × 103 kJ 
B)  +3.90 × 103 kJ 
C)  -2.04 × 103 kJ 
D)  -3.15 × 103 kJ 
E)  -3.30 × 103 kJ 
A)  +4.90 × 103 kJ 
B)  +3.90 × 103 kJ 
C)  -2.04 × 103 kJ 
D)  -3.15 × 103 kJ 
E)  -3.30 × 103 kJ

Question 3

What is true if ln K is positive?

Accepted Answer

A)  ΔG°rxn is positive and the reaction is spontaneous in the forward direction. 
B)  ΔG°rxn is negative and the reaction is spontaneous in the forward direction. 
C)  ΔG°rxn is negative and the reaction is spontaneous in the reverse direction. 
D)  ΔG°rxn is positive and the reaction is spontaneous in the reverse direction. 
E)  ΔG°rxn is zero and the reaction is at equilibrium. 
A)  ΔG°rxn is positive and the reaction is spontaneous in the forward direction. 
B)  ΔG°rxn is negative and the reaction is spontaneous in the forward direction. 
C)  ΔG°rxn is negative and the reaction is spontaneous in the reverse direction. 
D)  ΔG°rxn is positive and the reaction is spontaneous in the reverse direction. 
E)  ΔG°rxn is zero and the reaction is at equilibrium.

Question 4

Identify the compound with the highest standard free energy of formation.

Accepted Answer

A)  KCl(s) 
B)  H2(g) 
C)  CO2(l) 
D)  O3(g) 
E)  It is hard to determine. 
A)  KCl(s) 
B)  H2(g) 
C)  CO2(l) 
D)  O3(g) 
E)  It is hard to determine.

Question 5

Which of the following processes has a ΔS > 0?

Accepted Answer

A)  2 NH3(g) + CO2(g) → NH2CONH2(aq) + H2O(l) 
B)  lithium fluoride forms from its elements 
C)  2 HCl(g) → H2(g) + Cl2(l) 
D)  cesium chloride dissolves in pure water 
E)  All of the above processes have a ΔS > 0. 
A)  2 NH3(g) + CO2(g) → NH2CONH2(aq) + H2O(l) 
B)  lithium fluoride forms from its elements 
C)  2 HCl(g) → H2(g) + Cl2(l) 
D)  cesium chloride dissolves in pure water 
E)  All of the above processes have a ΔS > 0.

Question 6

Determine the equilibrium constant for the following reaction at 298 K. Cl(g)+ O3(g)→ ClO(g)+ O2(g)ΔG° = - 34.5 kJ

Accepted Answer

A)  5.66 × 105 
B)  0.986 
C)  8.96 × 10-7 
D)  4.98 × 10-4 
E)  1.12 × 106 
A)  5.66 × 105 
B)  0.986 
C)  8.96 × 10-7 
D)  4.98 × 10-4 
E)  1.12 × 106

Question 7

Which of the following relationships is correct at constant T and P?

Accepted Answer

A) ΔG is proportional to -ΔSuniv B) ΔG > 0 represents a spontaneous process C) ΔG > 0 represents an increase in kinetic energy D) ΔG < 0 represents a nonspontaneous process E) All of the above are correct A) ΔG is proportional to -ΔSuniv B) ΔG > 0 represents a spontaneous process C) ΔG > 0 represents an increase in kinetic energy D) ΔG < 0 represents a nonspontaneous process E) All of the above are correct

Question 8

Calculate the ΔG°rxn using the following information. 2 HNO3(aq)+ NO(g)→ 3 NO2(g)+ H2O(l)ΔG°rxn = ?
ΔH°f (kJ/mol)-207.0 91.3 33.2 -285.8
S°(J/mol∙K 146.0 210.8 240.1 70.0

Accepted Answer

A)  -151 kJ 
B)  -85.5 kJ 
C)  +50.8 kJ 
D)  -222 kJ 
E)  +101.6 kJ 
A)  -151 kJ 
B)  -85.5 kJ 
C)  +50.8 kJ 
D)  -222 kJ 
E)  +101.6 kJ

Question 9

Consider a reaction that has a positive ΔH and a positive ΔS.Which of the following statements is TRUE?

Accepted Answer

A)  This reaction will be spontaneous only at low temperatures. 
B)  This reaction will be spontaneous at all temperatures. 
C)  This reaction will be nonspontaneous at all temperatures. 
D)  This reaction will be nonspontaneous only at low temperatures. 
E)  It is not possible to determine without more information. 
A)  This reaction will be spontaneous only at low temperatures. 
B)  This reaction will be spontaneous at all temperatures. 
C)  This reaction will be nonspontaneous at all temperatures. 
D)  This reaction will be nonspontaneous only at low temperatures. 
E)  It is not possible to determine without more information.

Question 10

Calculate the ΔG°rxn using the following information. 2 H2S(g)+ 3 O2(g)→ 2 SO2(g)+ 2 H2O(g)ΔG°rxn = ?
ΔG°f (kJ/mol)-33.4 -300.1 -228.6

Accepted Answer

A)  +990.6 kJ 
B)  -562.1 kJ 
C)  -1124 kJ 
D)  -72.0 kJ 
E)  -990.6 kJ 
A)  +990.6 kJ 
B)  -562.1 kJ 
C)  -1124 kJ 
D)  -72.0 kJ 
E)  -990.6 kJ

Question 11

Calculate ΔS°rxn for the following reaction.The S∘ for each species is shown below the reaction. C2H2(g)+ 2 H2(g)→ C2H6(g)
S°(J/mol∙K)200.9 130.7 229.2

Accepted Answer

A)  -303.3 J/K 
B)  -560.8 J/K 
C)  -159.0 J/K 
D)  -233.1 J/K 
E)  +233.1 J/K 
A)  -303.3 J/K 
B)  -560.8 J/K 
C)  -159.0 J/K 
D)  -233.1 J/K 
E)  +233.1 J/K

Question 12

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ?
ΔG°f (kJ/mol)-73.5 149.3 -237.1

Accepted Answer

A)  -3.298 × 103 kJ 
B)  +312.9 kJ 
C)  +3.298 × 103 kJ 
D)  +110.7 kJ 
E)  +14.3 kJ 
A)  -3.298 × 103 kJ 
B)  +312.9 kJ 
C)  +3.298 × 103 kJ 
D)  +110.7 kJ 
E)  +14.3 kJ

Question 13

Given the following equation, N2O(g)+ NO2(g)→ 3 NO(g)ΔG°rxn = -23.0 kJ
Calculate ΔG°rxn for the following reaction.
3 NO(g)→ N2O(g)+ NO2(g)

Accepted Answer

A)  -23.0 kJ 
B)  69.0 kJ 
C)  -69.0 kJ 
D)  -7.67 kJ 
E)  23.0 kJ 
A)  -23.0 kJ 
B)  69.0 kJ 
C)  -69.0 kJ 
D)  -7.67 kJ 
E)  23.0 kJ

Question 14

Determine ΔG°rxn using the following information. H2(g)+ CO(g)→ CH2O(g)ΔH°= +1.9 kJ; ΔS°= -109.6 J/K

Accepted Answer

A)  +57.7 kJ 
B)  +30.8 kJ 
C)  +34.6 kJ 
D)  +41.5 kJ 
E)  -17.3 kJ 
A)  +57.7 kJ 
B)  +30.8 kJ 
C)  +34.6 kJ 
D)  +41.5 kJ 
E)  -17.3 kJ

Question 15

Determine ΔG°rxn for the following reaction at 338 K. FeO(s)+ CO(g)→ Fe(s)+ CO2(g)ΔH°= -11.0 kJ; ΔS°= -17.4 J/K

Accepted Answer

A)  +191.0 kJ 
B)  -5.1 kJ 
C)  +5.1 kJ 
D)  -16.1 kJ 
E)  +16.1 kJ 
A)  +191.0 kJ 
B)  -5.1 kJ 
C)  +5.1 kJ 
D)  -16.1 kJ 
E)  +16.1 kJ

Question 16

Calculate ΔGrxn at 298 K under the conditions shown below for the following reaction. CaCO3(s)→ CaO(s)+ CO2(g)ΔG° = +131.1 kJ
P(CO2)= 0.033 atm

Accepted Answer

A)  -49.3 kJ 
B)  -8.32 kJ 
C)  +122.6 kJ 
D)  +39.7 kJ 
E)  +43.3 kJ 
A)  -49.3 kJ 
B)  -8.32 kJ 
C)  +122.6 kJ 
D)  +39.7 kJ 
E)  +43.3 kJ

Question 17

For the following example,identify the following. 2 N2O(g)→ 2 N2(g)+ O2(g)

Accepted Answer

A)  a negative ΔH and a negative ΔS 
B)  a positive ΔH and a negative ΔS 
C)  a negative ΔH and a positive ΔS 
D)  a positive ΔH and a positive ΔS 
E)  It is not possible to determine without more information. 
A)  a negative ΔH and a negative ΔS 
B)  a positive ΔH and a negative ΔS 
C)  a negative ΔH and a positive ΔS 
D)  a positive ΔH and a positive ΔS 
E)  It is not possible to determine without more information.

Question 18

Place the following in order of decreasing molar entropy at 298 K. HF N2H4 Ar

Accepted Answer

A)  Ar > N2H4 > HF 
B)  Ar > HF > N2H4 
C)  N2H4 > Ar > HF 
D)  N2H4 > HF > Ar 
E)  HF > N2H4 > Ar 
A)  Ar > N2H4 > HF 
B)  Ar > HF > N2H4 
C)  N2H4 > Ar > HF 
D)  N2H4 > HF > Ar 
E)  HF > N2H4 > Ar

Question 19

Identify the process that is endothermic.

Accepted Answer

A)  vaporization 
B)  deposition 
C)  freezing 
D)  condensation 
A)  vaporization 
B)  deposition 
C)  freezing 
D)  condensation

Question 20

Which of the following processes has a ΔS > 0?

Accepted Answer

A)  SO2 (l) → SO2 (s) 
B)  N2(g) + 3 H2(g) → 2 NH3(g) 
C)  CH4(g) + H2O(g) → CO(g) + 3 H2(g) 
D)  K2CO3(s) + H2O(g) + CO2(g) → 2 KHCO3(s) 
E)  All of the above processes have a ΔS > 0. 
A)  SO2 (l) → SO2 (s) 
B)  N2(g) + 3 H2(g) → 2 NH3(g) 
C)  CH4(g) + H2O(g) → CO(g) + 3 H2(g) 
D)  K2CO3(s) + H2O(g) + CO2(g) → 2 KHCO3(s) 
E)  All of the above processes have a ΔS > 0.

Exam 18: Free Energy and Thermodynamics

Determine the equilibrium constant for the following reaction at 498 K. 2 Hg(g)+ O2(g)→ 2 HgO(s)ΔH° = -304.2 kJ; ΔS° = -414.2 J/K

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ? ΔH°f (kJ/mol)-133.9 50.6 -285.8 S°(J/mol∙K)266.9 121.2 191.6 70.0

What is true if ln K is positive?

Identify the compound with the highest standard free energy of formation.

Which of the following processes has a ΔS > 0?

Determine the equilibrium constant for the following reaction at 298 K. Cl(g)+ O3(g)→ ClO(g)+ O2(g)ΔG° = - 34.5 kJ

Which of the following relationships is correct at constant T and P?

Calculate the ΔG°rxn using the following information. 2 HNO3(aq)+ NO(g)→ 3 NO2(g)+ H2O(l)ΔG°rxn = ? ΔH°f (kJ/mol)-207.0 91.3 33.2 -285.8 S°(J/mol∙K 146.0 210.8 240.1 70.0

Consider a reaction that has a positive ΔH and a positive ΔS.Which of the following statements is TRUE?

Calculate the ΔG°rxn using the following information. 2 H2S(g)+ 3 O2(g)→ 2 SO2(g)+ 2 H2O(g)ΔG°rxn = ? ΔG°f (kJ/mol)-33.4 -300.1 -228.6

Calculate ΔS°rxn for the following reaction.The S∘ for each species is shown below the reaction. C2H2(g)+ 2 H2(g)→ C2H6(g) S°(J/mol∙K)200.9 130.7 229.2

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ? ΔG°f (kJ/mol)-73.5 149.3 -237.1

Given the following equation, N2O(g)+ NO2(g)→ 3 NO(g)ΔG°rxn = -23.0 kJ Calculate ΔG°rxn for the following reaction. 3 NO(g)→ N2O(g)+ NO2(g)

Determine ΔG°rxn using the following information. H2(g)+ CO(g)→ CH2O(g)ΔH°= +1.9 kJ; ΔS°= -109.6 J/K

Determine ΔG°rxn for the following reaction at 338 K. FeO(s)+ CO(g)→ Fe(s)+ CO2(g)ΔH°= -11.0 kJ; ΔS°= -17.4 J/K

Calculate ΔGrxn at 298 K under the conditions shown below for the following reaction. CaCO3(s)→ CaO(s)+ CO2(g)ΔG° = +131.1 kJ P(CO2)= 0.033 atm

For the following example,identify the following. 2 N2O(g)→ 2 N2(g)+ O2(g)

Place the following in order of decreasing molar entropy at 298 K. HF N2H4 Ar

Identify the process that is endothermic.

Which of the following processes has a ΔS > 0?

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Determine the equilibrium constant for the following reaction at 498 K. 2 Hg(g)+ O₂(g)→ 2 HgO(s)ΔH° = -304.2 kJ; ΔS° = -414.2 J/K

Calculate the ΔG°_rxn using the following information. 4 HNO₃(g)+ 5 N₂H₄(l)→ 7 N₂(g)+ 12 H₂O(l)ΔG°_rxn= ? ΔH°_f (kJ/mol)-133.9 50.6 -285.8 S°(J/mol∙K)266.9 121.2 191.6 70.0

Determine the equilibrium constant for the following reaction at 298 K. Cl(g)+ O₃(g)→ ClO(g)+ O₂(g)ΔG° = - 34.5 kJ

Calculate the ΔG°_rxn using the following information. 2 HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)ΔG°_rxn= ? ΔH°_f (kJ/mol)-207.0 91.3 33.2 -285.8 S°(J/mol∙K 146.0 210.8 240.1 70.0

Calculate the ΔG°_rxn using the following information. 2 H₂S(g)+ 3 O₂(g)→ 2 SO₂(g)+ 2 H₂O(g)ΔG°_rxn= ? ΔG°_f (kJ/mol)-33.4 -300.1 -228.6

Calculate ΔS°_rxn for the following reaction.The S^∘for each species is shown below the reaction. C₂H₂(g)+ 2 H₂(g)→ C₂H₆(g) S°(J/mol∙K)200.9 130.7 229.2

Calculate the ΔG°_rxn using the following information. 4 HNO₃(g)+ 5 N₂H₄(l)→ 7 N₂(g)+ 12 H₂O(l)ΔG°_rxn= ? ΔG°_f (kJ/mol)-73.5 149.3 -237.1

Given the following equation, N₂O(g)+ NO₂(g)→ 3 NO(g)ΔG°_rxn = -23.0 kJ Calculate ΔG°_rxn for the following reaction. 3 NO(g)→ N₂O(g)+ NO₂(g)

Determine ΔG°_rxn using the following information. H₂(g)+ CO(g)→ CH₂O(g)ΔH°= +1.9 kJ; ΔS°= -109.6 J/K

Determine ΔG°_rxn for the following reaction at 338 K. FeO(s)+ CO(g)→ Fe(s)+ CO₂(g)ΔH°= -11.0 kJ; ΔS°= -17.4 J/K

Calculate ΔG_rxn at 298 K under the conditions shown below for the following reaction. CaCO₃(s)→ CaO(s)+ CO₂(g)ΔG° = +131.1 kJ P(CO₂)= 0.033 atm

For the following example,identify the following. 2 N₂O(g)→ 2 N₂(g)+ O₂(g)

Place the following in order of decreasing molar entropy at 298 K. HF N₂H₄ Ar