Question 1

Place the following in order of increasing standard molar entropy. H2O(l)H2O(g)H2O(s)

Accepted Answer

A) H2O(g)2O(l)2O(s) 
B) H2O(s)2O(l)2O(g) 
C) H2O(g)2O(s)2O(l) 
D) H2O(l)2O(s)2O(g) 
E) H2O(s)2O(g)2O(l) 
A) H2O(g)2O(l)2O(s) 
B) H2O(s)2O(l)2O(g) 
C) H2O(g)2O(s)2O(l) 
D) H2O(l)2O(s)2O(g) 
E) H2O(s)2O(g)2O(l)

Question 2

Consider a reaction that has a negative ΔrH and a positive ΔrS. Which of the following statements is TRUE?

Accepted Answer

A) This reaction will be spontaneous only at high 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 high temperatures. 
E) This reaction will be spontaneous only at absolute zero (0 Kelvin). 
A) This reaction will be spontaneous only at high 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 high temperatures. 
E) This reaction will be spontaneous only at absolute zero (0 Kelvin).

Question 3

For a given reaction, ΔrH = +35.5 kJ mol-1 and ΔrS = +83.6 J K-1 mol-1. The reaction is spontaneous ________. Assume that ΔrH and ΔrS do not vary with temperature.

Accepted Answer

A) at T 425 K C) at all temperatures D) at T > 298 K E) at T < 298 K A) at T 425 K C) at all temperatures D) at T > 298 K E) at T < 298 K

Question 4

Define the third law of thermodynamics.

Accepted Answer

The entropy of a per

Question 5

Identify the change in state that does not have an increase in entropy.

Accepted Answer

A) water freezing 
B) water boiling 
C) ice melting 
D) dry ice subliming 
E) water evaporating 
A) water freezing 
B) water boiling 
C) ice melting 
D) dry ice subliming 
E) water evaporating

Question 6

The value of ΔfG° at 141.0 °C for the formation of phosphorus trichloride from its constituent elements, P2(g)+ 3Cl2(g) → 2PCl3(g)
Is __________ kJ mol-1. At 25.0 °C for this reaction, ΔfH° is -720.5 kJ mol-1 and ΔfS° is -263.7 J K-1 mol-1.

Accepted Answer

A) -611.3 
B) 3.65 × 104 
C) 1.08 × 105 
D) -683.3 
E) -829.7 
A) -611.3 
B) 3.65 × 104 
C) 1.08 × 105 
D) -683.3 
E) -829.7

Question 7

Why can endothermic reactions be spontaneous?

Accepted Answer

Even though an endothermic process requi

Question 8

Determine ΔrG° at 298 K using the following information: CaCO3(s)→ CaO(s)+ CO2(g)ΔrH°= +179.2 kJ mol-1; ΔrS°= +160.2 J K-1 mol-1

Accepted Answer

A) -607.0 kJ mol-1 
B) +112 .0 kJ mol-1 
C) -89.3 kJ mol-1 
D) +131.4 kJ mol-1 
E) +228.1 kJ mol-1 
A) -607.0 kJ mol-1 
B) +112 .0 kJ mol-1 
C) -89.3 kJ mol-1 
D) +131.4 kJ mol-1 
E) +228.1 kJ mol-1

Question 9

Under which of the following conditions would one mole of He have the highest entropy, S?

Accepted Answer

A) 17 °C and 15 L 
B) 127 °C and 15 L 
C) 17 °C and 25 L 
D) 127 °C and 25 L 
A) 17 °C and 15 L 
B) 127 °C and 15 L 
C) 17 °C and 25 L 
D) 127 °C and 25 L

Question 10

Calculate ΔrG° at 298 K using the following information: 4HNO3(g)+ 5N2H4(l)→ 7N2(g)+ 12H2O(l)ΔrG° = ?
ΔfG° (kJ mol-1)-73.5 149.3 -237.1

Accepted Answer

A) -3.2977 × 103 kJ mol-1 
B) -312.9 kJ mol-1 
C) +2.845 × 103 kJ mol-1 
D) +110.7 kJ mol-1 
E) -954.7 kJ mol-1 
A) -3.2977 × 103 kJ mol-1 
B) -312.9 kJ mol-1 
C) +2.845 × 103 kJ mol-1 
D) +110.7 kJ mol-1 
E) -954.7 kJ mol-1

Question 11

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: SO3(g)+ H2O(g)→ H2SO4(l)ΔrG°= -90.5 kJ mol-1
P(SO3)= 0.20 atm, P(H2O)= 0.88 atm

Accepted Answer

A) +15.9 kJ mol-1 
B) -90.5 kJ mol-1 
C) +51.4 kJ mol-1 
D) -86.2 kJ mol-1 
E) -30.4 kJ mol-1 
A) +15.9 kJ mol-1 
B) -90.5 kJ mol-1 
C) +51.4 kJ mol-1 
D) -86.2 kJ mol-1 
E) -30.4 kJ mol-1

Question 12

Which of the following statements is TRUE?

Accepted Answer

A) A spontaneous reaction is a reaction that takes place without any outside intervention. 
B) Thermodynamics is a study of reaction rates. 
C) A nonspontaneous reaction is a reaction that does not take place under any conditions. 
D) Chemical kinetics is a discipline that studies the spontaneity of chemical reactions. 
E) Every spontaneous reaction is a very rapid reaction. 
A) A spontaneous reaction is a reaction that takes place without any outside intervention. 
B) Thermodynamics is a study of reaction rates. 
C) A nonspontaneous reaction is a reaction that does not take place under any conditions. 
D) Chemical kinetics is a discipline that studies the spontaneity of chemical reactions. 
E) Every spontaneous reaction is a very rapid reaction.

Question 13

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

Accepted Answer

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

Question 14

Which of the following statements is TRUE?

Accepted Answer

A) Entropy is an extensive property. 
B) Entropy is not temperature dependent. 
C) Exothermic processes decrease the entropy of the surroundings. 
D) ΔSuniv is always greater than zero for a nonspontaneous process. 
E) Just like enthalpy, entropy has no absolute zero value. 
A) Entropy is an extensive property. 
B) Entropy is not temperature dependent. 
C) Exothermic processes decrease the entropy of the surroundings. 
D) ΔSuniv is always greater than zero for a nonspontaneous process. 
E) Just like enthalpy, entropy has no absolute zero value.

Question 15

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

Accepted Answer

A) NaCl(s) 
B) N2(g) 
C) NO(g) 
D) O3(g) 
E) Cl2(g) 
A) NaCl(s) 
B) N2(g) 
C) NO(g) 
D) O3(g) 
E) Cl2(g)

Question 16

Which one of the following would be expected to have the lowest standard molar entropy, S°, at 25 °C?

Accepted Answer

A) C10H22(s) 
B) C10H22(l) 
C) C14H30(s) 
D) C14 H30OH(l) 
A) C10H22(s) 
B) C10H22(l) 
C) C14H30(s) 
D) C14 H30OH(l)

Question 17

Calculate ΔrS° for the following reaction. The S∘ for each species is shown below the reaction. C2H2(g)+ 2H2(g)→ C2H6(g)
S°(J K-1 mol-1)200.9 130.7 229.2

Accepted Answer

A) +303.3 J K-1 mol-1 
B) +560.8 J K-1 mol-1 
C) -102.4 J K-1 mol-1 
D) -233.1 J K-1 mol-1 
E) 229.2 J K-1 mol-1 
A) +303.3 J K-1 mol-1 
B) +560.8 J K-1 mol-1 
C) -102.4 J K-1 mol-1 
D) -233.1 J K-1 mol-1 
E) 229.2 J K-1 mol-1

Question 18

Match the following.

-Q > 1

Accepted Answer

A) K = 0 
B) ?rG > 0 
C) ($\Delta$rG rG rG° 
E) equilibrium
F)?rG > ?rG°
G)standard state 
A) K = 0 
B) ?rG > 0 
C) ($\Delta$rG rG rG° 
E) equilibrium
F)?rG > ?rG°
G)standard state

Question 19

For the following example, what is true about ΔrH and ΔrS? H2O(l)→ H2O(s)

Accepted Answer

A) a negative ΔrH and a negative ΔrS 
B) a positive ΔrH and a negative ΔrS 
C) a negative ΔrH and a positive ΔrS 
D) a positive ΔrH and a positive ΔrS 
E)  ΔrH = 0 and a positive ΔrS 
A) a negative ΔrH and a negative ΔrS 
B) a positive ΔrH and a negative ΔrS 
C) a negative ΔrH and a positive ΔrS 
D) a positive ΔrH and a positive ΔrS 
E)  ΔrH = 0 and a positive ΔrS

Question 20

Determine the equilibrium constant for the following reaction at 655 K: HCN(g)+ 2H2(g)→ CH3NH2(g)ΔrH° = -158 kJ mol-1; ΔrS°= -219.9 J K-1 mol-1

Accepted Answer

A) 3.99 × 1012 
B) 13.0 
C) 2.51 × 10-13 
D) 3.26 × 10-12 
E) 3.07 × 1011 
A) 3.99 × 1012 
B) 13.0 
C) 2.51 × 10-13 
D) 3.26 × 10-12 
E) 3.07 × 1011

Exam 17: Gibbs Energy and Thermodynamics

Place the following in order of increasing standard molar entropy. H2O(l)H2O(g)H2O(s)

Consider a reaction that has a negative ΔrH and a positive ΔrS. Which of the following statements is TRUE?

For a given reaction, ΔrH = +35.5 kJ mol-1 and ΔrS = +83.6 J K-1 mol-1. The reaction is spontaneous ________. Assume that ΔrH and ΔrS do not vary with temperature.

Define the third law of thermodynamics.

Identify the change in state that does not have an increase in entropy.

The value of ΔfG° at 141.0 °C for the formation of phosphorus trichloride from its constituent elements, P2(g)+ 3Cl2(g) → 2PCl3(g) Is __________ kJ mol-1. At 25.0 °C for this reaction, ΔfH° is -720.5 kJ mol-1 and ΔfS° is -263.7 J K-1 mol-1.

Why can endothermic reactions be spontaneous?

Determine ΔrG° at 298 K using the following information: CaCO3(s)→ CaO(s)+ CO2(g)ΔrH°= +179.2 kJ mol-1; ΔrS°= +160.2 J K-1 mol-1

Under which of the following conditions would one mole of He have the highest entropy, S?

Calculate ΔrG° at 298 K using the following information: 4HNO3(g)+ 5N2H4(l)→ 7N2(g)+ 12H2O(l)ΔrG° = ? ΔfG° (kJ mol-1)-73.5 149.3 -237.1

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: SO3(g)+ H2O(g)→ H2SO4(l)ΔrG°= -90.5 kJ mol-1 P(SO3)= 0.20 atm, P(H2O)= 0.88 atm

Which of the following statements is TRUE?

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

Which of the following statements is TRUE?

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

Which one of the following would be expected to have the lowest standard molar entropy, S°, at 25 °C?

Calculate ΔrS° for the following reaction. The S∘ for each species is shown below the reaction. C2H2(g)+ 2H2(g)→ C2H6(g) S°(J K-1 mol-1)200.9 130.7 229.2

Match the following. -Q > 1

For the following example, what is true about ΔrH and ΔrS? H2O(l)→ H2O(s)

Determine the equilibrium constant for the following reaction at 655 K: HCN(g)+ 2H2(g)→ CH3NH2(g)ΔrH° = -158 kJ mol-1; ΔrS°= -219.9 J K-1 mol-1

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Place the following in order of increasing standard molar entropy. H₂O(l)H₂O(g)H₂O(s)

Consider a reaction that has a negative Δ_rH and a positive Δ_rS. Which of the following statements is TRUE?

For a given reaction, Δ_rH = +35.5 kJ mol^-1 and Δ_rS = +83.6 J K^-1mol^-1. The reaction is spontaneous ________. Assume that Δ_rH and Δ_rS do not vary with temperature.

The value of Δ_fG° at 141.0 °C for the formation of phosphorus trichloride from its constituent elements, P₂(g)+ 3Cl₂(g) → 2PCl₃(g) Is __________ kJ mol^-1. At 25.0 °C for this reaction, Δ_fH° is -720.5 kJ mol^-1 and Δ_fS° is -263.7 J K^-1 mol^-1.

Determine Δ_rG° at 298 K using the following information: CaCO₃(s)→ CaO(s)+ CO₂(g)Δ_rH°= +179.2 kJ mol^-1; Δ_rS°= +160.2 J K^-1 mol^-1

Calculate Δ_rG° at 298 K using the following information: 4HNO₃(g)+ 5N₂H₄(l)→ 7N₂(g)+ 12H₂O(l)Δ_rG°= ? Δ_fG° (kJ mol^-1)-73.5 149.3 -237.1

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: SO₃(g)+ H₂O(g)→ H₂SO₄(l)Δ_rG°= -90.5 kJ mol^-1 P(SO₃)= 0.20 atm, P(H₂O)= 0.88 atm

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

Calculate Δ_rS° for the following reaction. The S^∘for each species is shown below the reaction. C₂H₂(g)+ 2H₂(g)→ C₂H₆(g) S°(J K^-1 mol^-1)200.9 130.7 229.2

For the following example, what is true about Δ_rH and Δ_rS? H₂O(l)→ H₂O(s)

Determine the equilibrium constant for the following reaction at 655 K: HCN(g)+ 2H₂(g)→ CH₃NH₂(g)Δ_rH° = -158 kJ mol^-1; Δ_rS°= -219.9 J K^-1 mol^-1