Question 1

Given the following,determine S° at 298 K for one mole of NO(g).
2NO(g)+ O2(g)→ 2NO2(g); ΔS° = −146.7 J/K at 298K

Accepted Answer

A) 210.9 J/K 
B) −90.85 J/K 
C) 421.7 J/K 
D) -421.7 J/K 
E) +90.85 J/K 
A) 210.9 J/K 
B) −90.85 J/K 
C) 421.7 J/K 
D) -421.7 J/K 
E) +90.85 J/K

Question 2

For which of the following reactions is ΔS° > 0 at 25°C?

Accepted Answer

A) MgO(s)+ CO2(g)→ MgCO3(s) 
B) 2H2(g)+ O2(l)→ 2H2O(l) 
C) 2Li(s)+ O2(g)→ Li2O(s) 
D) 2CO(g)+ O2(g)→ 2CO2(g) 
E) F3BNH3(s)→ BF3(g)+ NH3(g) 
A) MgO(s)+ CO2(g)→ MgCO3(s) 
B) 2H2(g)+ O2(l)→ 2H2O(l) 
C) 2Li(s)+ O2(g)→ Li2O(s) 
D) 2CO(g)+ O2(g)→ 2CO2(g) 
E) F3BNH3(s)→ BF3(g)+ NH3(g)

Question 3

Given the following,determine ΔG°f at 298 K for SnO.
Sn(s)+ SnO2(s)→ 2SnO(s); ΔG° = 12.0 kJ at 298K

Accepted Answer

A) -251.9 kJ/mol 
B) -503.8 kJ/mol 
C) 527.8 kJ/mol 
D) 263.9 kJ/mol 
E) 1055.6 kJ/mol 
A) -251.9 kJ/mol 
B) -503.8 kJ/mol 
C) 527.8 kJ/mol 
D) 263.9 kJ/mol 
E) 1055.6 kJ/mol

Question 4

Consider the following reaction:
CaO(s)+ CO2(g)→ CaCO3(s); ΔG° = -130.9 kJ at 298 K
At what partial pressure of CO2(g)will the reaction no longer be spontaneous at 298 K? (R = 0.0821 L ∙ atm/(K ∙ mol)= 8.31 J/(K ∙ mol))

Accepted Answer

A) 1.59 × 108 atm 
B) 1.00 atm 
C) 6.28 × 10-9 atm 
D) 8.77 × 1022 atm 
E) 1.14 × 10-23 atm 
A) 1.59 × 108 atm 
B) 1.00 atm 
C) 6.28 × 10-9 atm 
D) 8.77 × 1022 atm 
E) 1.14 × 10-23 atm

Question 5

For a reaction that has an equilibrium constant of 6 × 109,which of the following statements must be true?

Accepted Answer

A) ΔS° is positive. 
B) ΔG° is negative. 
C) ΔG° is positive. 
D) ΔH° is negative. 
E) ΔH° is positive. 
A) ΔS° is positive. 
B) ΔG° is negative. 
C) ΔG° is positive. 
D) ΔH° is negative. 
E) ΔH° is positive.

Question 6

Which of the following statements is true concerning the reaction below?
CH4(g)+ N2(g)→ HCN(g)+ NH3(g); ΔH° = 164.1 kJ; ΔG° = 159.1 kJ at 298 K

Accepted Answer

A) It is nonspontaneous at all temperatures. 
B) It is spontaneous at relatively low temperatures only. 
C) It is spontaneous at all temperatures. 
D) It is at equilibrium at 298 K. 
E) It is spontaneous at relatively high temperatures only. 
A) It is nonspontaneous at all temperatures. 
B) It is spontaneous at relatively low temperatures only. 
C) It is spontaneous at all temperatures. 
D) It is at equilibrium at 298 K. 
E) It is spontaneous at relatively high temperatures only.

Question 7

Which of the following is true for the reaction NH3(l)   NH3(g)at -33°C and 1 atm pressure? (The normal boiling point for NH3 is -33°C.)

Accepted Answer

A) ΔH = TΔS 
B) ΔH = 0 
C) ΔH = ΔnRT 
D) ΔS = 0 
E) ΔH = PΔV 
A) ΔH = TΔS 
B) ΔH = 0 
C) ΔH = ΔnRT 
D) ΔS = 0 
E) ΔH = PΔV

Question 8

For the process Cl2(g)→ 2Cl(g),

Accepted Answer

A) ΔH is + and ΔS is + for the reaction. 
B) ΔH is + and ΔS = 0 for the reaction. 
C) ΔH is - and ΔS is - for the reaction. 
D) ΔH is - and ΔS is + for the reaction. 
E) ΔH is + and ΔS is - for the reaction. 
A) ΔH is + and ΔS is + for the reaction. 
B) ΔH is + and ΔS = 0 for the reaction. 
C) ΔH is - and ΔS is - for the reaction. 
D) ΔH is - and ΔS is + for the reaction. 
E) ΔH is + and ΔS is - for the reaction.

Question 9

A gas absorbs 0.0 J of heat and then performs 99.5 J of work.What is the change in internal energy of the gas?

Accepted Answer

A) -99.5 J 
B) 59.5 J 
C) 139.5 J 
D) 99.1 J 
E) none of these 
A) -99.5 J 
B) 59.5 J 
C) 139.5 J 
D) 99.1 J 
E) none of these

Question 10

Which of the following compounds has the highest standard entropy per mole at 298 K?

Accepted Answer

A) H2O(l) 
B) CaCO3(s) 
C) CO(g) 
D) SiO2(s) 
E) CH3OH(l) 
A) H2O(l) 
B) CaCO3(s) 
C) CO(g) 
D) SiO2(s) 
E) CH3OH(l)

Question 11

A system under constant external pressure undergoes a decrease in volume.What is the effect on the surroundings?

Accepted Answer

A) Energy is transferred as pressure-volume work done by the surroundings on the system. 
B) Energy is transferred as pressure-volume work done on the surroundings. 
C) Energy is transferred as heat from the system to the surroundings. 
D) Energy is transferred as heat from the surroundings to the system. 
E) None of the above. 
A) Energy is transferred as pressure-volume work done by the surroundings on the system. 
B) Energy is transferred as pressure-volume work done on the surroundings. 
C) Energy is transferred as heat from the system to the surroundings. 
D) Energy is transferred as heat from the surroundings to the system. 
E) None of the above.

Question 12

From these two reactions at 298 K,
V2O3(s)+ 3CO(g)→ 2V(s)+ 3CO2(g); ΔH° = 369.8 kJ; ΔS° = 8.3 J/K
V2O5(s)+ 2CO(g)→ V2O3(s)+ 2CO2(g); ΔH° = -234.2 kJ; ΔS° = 0.2 J/K
Calculate ΔG° for the following at 298 K:
2V(s)+ 5CO2(g)→ V2O5(s)+ 5CO(g)

Accepted Answer

A) +133.1 kJ 
B) +601.6 kJ 
C) -601.6 kJ 
D) -133.1 kJ 
E) +1.6 kJ 
A) +133.1 kJ 
B) +601.6 kJ 
C) -601.6 kJ 
D) -133.1 kJ 
E) +1.6 kJ

Question 13

Consider the following reaction:
2AgCl(s)→ 2Ag(s)+ Cl2(g); ΔH° = 127.1 kJ; ΔS° = 115.7 J/K at 298 K
Suppose 61.4 g of silver(I)chloride is placed in a 50.0 L vessel at 298 K.What is the equilibrium partial pressure of chlorine gas? (R = 0.0821 L ∙ atm/(K ∙ mol)= 8.31 J/(K ∙ mol))

Accepted Answer

A) 0.100 atm 
B) 5.1 × 10-23 atm 
C) 0.950 atm 
D) 0.210 atm 
E) 5.7 × 10-17 atm 
A) 0.100 atm 
B) 5.1 × 10-23 atm 
C) 0.950 atm 
D) 0.210 atm 
E) 5.7 × 10-17 atm

Question 14

Sublimation is an example of a process for which

Accepted Answer

A) ΔH is positive and ΔS is negative at all temperatures. 
B) ΔH is negative and ΔS is positive at all temperatures. 
C) ΔH,ΔS,and ΔG are negative at all temperatures. 
D) ΔH and ΔS are positive at all temperatures. 
E) ΔH,ΔS,and ΔG are positive at all temperatures. 
A) ΔH is positive and ΔS is negative at all temperatures. 
B) ΔH is negative and ΔS is positive at all temperatures. 
C) ΔH,ΔS,and ΔG are negative at all temperatures. 
D) ΔH and ΔS are positive at all temperatures. 
E) ΔH,ΔS,and ΔG are positive at all temperatures.

Question 15

For which of the following processes would ΔS° be expected to be most positive?

Accepted Answer

A) H2O(l)→ H2O(s) 
B) NH3(g)+ HCl(g)→ NH4Cl(s) 
C) O2(g)+ 2H2(g)→ 2H2O(g) 
D) N2O4(g)→ 2NO2(g) 
E) 2NH4NO3(s)→ 2N2(g)+ O2(g)+ 4H2O(g) 
A) H2O(l)→ H2O(s) 
B) NH3(g)+ HCl(g)→ NH4Cl(s) 
C) O2(g)+ 2H2(g)→ 2H2O(g) 
D) N2O4(g)→ 2NO2(g) 
E) 2NH4NO3(s)→ 2N2(g)+ O2(g)+ 4H2O(g)

Question 16

What is ΔG° at 298 K for the following reaction?
H2(g)+ Br2(g)→ 2HBr(g); ΔH° = -103.8 kJ; ΔS° = 21.3 J/K at 298 K

Accepted Answer

A) 97.45 kJ 
B) 111 kJ 
C) 110.1 kJ 
D) 6.451 × 103 kJ 
E) -6.451× 103 kJ 
A) 97.45 kJ 
B) 111 kJ 
C) 110.1 kJ 
D) 6.451 × 103 kJ 
E) -6.451× 103 kJ

Question 17

For a reversible phase change at constant temperature and pressure,

Accepted Answer

A) ΔG = 0. 
B) ΔU = 0. 
C) w = 0. 
D) ΔH = 0. 
E) q = 0. 
A) ΔG = 0. 
B) ΔU = 0. 
C) w = 0. 
D) ΔH = 0. 
E) q = 0.

Question 18

Which of the following is the best criterion for determining the spontaneity of a chemical reaction?

Accepted Answer

A) ΔH 
B) ΔH° 
C) ΔG 
D) ΔG° 
E) TΔS 
A) ΔH 
B) ΔH° 
C) ΔG 
D) ΔG° 
E) TΔS

Question 19

Condensation is a process for which

Accepted Answer

A) ΔG is negative at high temperature but positive at low temperature. 
B) ΔH,ΔS,and ΔG are positive at all temperatures. 
C) ΔG is positive when condensation occurs spontaneously. 
D) ΔH and ΔS are positive at all temperatures. 
E) ΔH and ΔS are negative at all temperatures. 
A) ΔG is negative at high temperature but positive at low temperature. 
B) ΔH,ΔS,and ΔG are positive at all temperatures. 
C) ΔG is positive when condensation occurs spontaneously. 
D) ΔH and ΔS are positive at all temperatures. 
E) ΔH and ΔS are negative at all temperatures.

Question 20

oWhat is the change in free energy at 298 K when 70.0 mL of 0.704 M calcium chloride is combined with 47.9 mL of 0.859 M sodium carbonate? (R = 8.31 J/(K ∙ mol))
Ca2+(aq)+ CO32-(aq)→ CaCO3(s)

Accepted Answer

A) 42.6 kJ 
B) -2.21 × 103 kJ 
C) 46.1 kJ 
D) 47.4 kJ 
E) 2.56 × 103 kJ 
A) 42.6 kJ 
B) -2.21 × 103 kJ 
C) 46.1 kJ 
D) 47.4 kJ 
E) 2.56 × 103 kJ

Exam 18: Thermodynamics and Equilibrium

Given the following,determine S° at 298 K for one mole of NO(g). 2NO(g)+ O2(g)→ 2NO2(g); ΔS° = −146.7 J/K at 298K

For which of the following reactions is ΔS° > 0 at 25°C?

Given the following,determine ΔG°f at 298 K for SnO. Sn(s)+ SnO2(s)→ 2SnO(s); ΔG° = 12.0 kJ at 298K

Consider the following reaction: CaO(s)+ CO2(g)→ CaCO3(s); ΔG° = -130.9 kJ at 298 K At what partial pressure of CO2(g)will the reaction no longer be spontaneous at 298 K? (R = 0.0821 L ∙ atm/(K ∙ mol)= 8.31 J/(K ∙ mol))

For a reaction that has an equilibrium constant of 6 × 109,which of the following statements must be true?

Which of the following statements is true concerning the reaction below? CH4(g)+ N2(g)→ HCN(g)+ NH3(g); ΔH° = 164.1 kJ; ΔG° = 159.1 kJ at 298 K

Which of the following is true for the reaction NH3(l) NH3(g)at -33°C and 1 atm pressure? (The normal boiling point for NH3 is -33°C.)

For the process Cl2(g)→ 2Cl(g),

A gas absorbs 0.0 J of heat and then performs 99.5 J of work.What is the change in internal energy of the gas?

Which of the following compounds has the highest standard entropy per mole at 298 K?

A system under constant external pressure undergoes a decrease in volume.What is the effect on the surroundings?

From these two reactions at 298 K, V2O3(s)+ 3CO(g)→ 2V(s)+ 3CO2(g); ΔH° = 369.8 kJ; ΔS° = 8.3 J/K V2O5(s)+ 2CO(g)→ V2O3(s)+ 2CO2(g); ΔH° = -234.2 kJ; ΔS° = 0.2 J/K Calculate ΔG° for the following at 298 K: 2V(s)+ 5CO2(g)→ V2O5(s)+ 5CO(g)

Consider the following reaction: 2AgCl(s)→ 2Ag(s)+ Cl2(g); ΔH° = 127.1 kJ; ΔS° = 115.7 J/K at 298 K Suppose 61.4 g of silver(I)chloride is placed in a 50.0 L vessel at 298 K.What is the equilibrium partial pressure of chlorine gas? (R = 0.0821 L ∙ atm/(K ∙ mol)= 8.31 J/(K ∙ mol))

Sublimation is an example of a process for which

For which of the following processes would ΔS° be expected to be most positive?

What is ΔG° at 298 K for the following reaction? H2(g)+ Br2(g)→ 2HBr(g); ΔH° = -103.8 kJ; ΔS° = 21.3 J/K at 298 K

For a reversible phase change at constant temperature and pressure,

Which of the following is the best criterion for determining the spontaneity of a chemical reaction?

Condensation is a process for which

oWhat is the change in free energy at 298 K when 70.0 mL of 0.704 M calcium chloride is combined with 47.9 mL of 0.859 M sodium carbonate? (R = 8.31 J/(K ∙ mol)) Ca2+(aq)+ CO32-(aq)→ CaCO3(s)

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Given the following,determine S° at 298 K for one mole of NO(g). 2NO(g)+ O₂(g)→ 2NO₂(g); ΔS° = −146.7 J/K at 298K

Given the following,determine ΔG°_f at 298 K for SnO. Sn(s)+ SnO₂(s)→ 2SnO(s); ΔG° = 12.0 kJ at 298K

Consider the following reaction: CaO(s)+ CO₂(g)→ CaCO₃(s); ΔG° = -130.9 kJ at 298 K At what partial pressure of CO₂(g)will the reaction no longer be spontaneous at 298 K? (R = 0.0821 L ∙ atm/(K ∙ mol)= 8.31 J/(K ∙ mol))

For a reaction that has an equilibrium constant of 6 × 10⁹,which of the following statements must be true?

Which of the following statements is true concerning the reaction below? CH₄(g)+ N₂(g)→ HCN(g)+ NH₃(g); ΔH° = 164.1 kJ; ΔG° = 159.1 kJ at 298 K

Which of the following is true for the reaction NH₃(l) NH₃(g)at -33°C and 1 atm pressure? (The normal boiling point for NH₃ is -33°C.)

For the process Cl₂(g)→ 2Cl(g),

From these two reactions at 298 K, V₂O₃(s)+ 3CO(g)→ 2V(s)+ 3CO₂(g); ΔH° = 369.8 kJ; ΔS° = 8.3 J/K V₂O₅(s)+ 2CO(g)→ V₂O₃(s)+ 2CO₂(g); ΔH° = -234.2 kJ; ΔS° = 0.2 J/K Calculate ΔG° for the following at 298 K: 2V(s)+ 5CO₂(g)→ V₂O₅(s)+ 5CO(g)

Consider the following reaction: 2AgCl(s)→ 2Ag(s)+ Cl₂(g); ΔH° = 127.1 kJ; ΔS° = 115.7 J/K at 298 K Suppose 61.4 g of silver(I)chloride is placed in a 50.0 L vessel at 298 K.What is the equilibrium partial pressure of chlorine gas? (R = 0.0821 L ∙ atm/(K ∙ mol)= 8.31 J/(K ∙ mol))

What is ΔG° at 298 K for the following reaction? H₂(g)+ Br₂(g)→ 2HBr(g); ΔH° = -103.8 kJ; ΔS° = 21.3 J/K at 298 K

oWhat is the change in free energy at 298 K when 70.0 mL of 0.704 M calcium chloride is combined with 47.9 mL of 0.859 M sodium carbonate? (R = 8.31 J/(K ∙ mol)) Ca²⁺(aq)+ CO₃^2-(aq)→ CaCO₃(s)