Question 1

In order for a process to be spontaneous,

Accepted Answer

A)  Δ H must be less than zero.
B)  Δ S must be greater than zero.
C)  Δ G must be greater than zero.
D)  it should be rapid.
E)  Δ S sys + Δ S surr must be greater than zero.F) B) and C)
G) A) and E)

Question 2

For a given reaction, a change in the pressure may result in a change in the sign of ΔG.

Accepted Answer

A) True 
 B)False

Question 3

The reaction of methane with water to form carbon dioxide and hydrogen is nonspontaneous at 298 K. At what temperature will this system make the transition from nonspontaneous to spontaneous? The data refer to 298 K. CH4(g)  + 2H2O(g)  ⇄ CO2(g)  + 4H2(g) 
4(g)  + 2H2O(g)  ⇄ CO2(g)  + 4H2(g)    A) 658 K B) 683 K C) 955 K D) 1047 K E) 1229 K" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  658 K
B)  683 K
C)  955 K
D)  1047 K
E)  1229 KF) A) and B)
G) All of the above

Question 4

Calculate ΔG° for the reaction of ammonia with fluorine. 2NH3(g)  + 5F2(g)  → N2F4(g)  + 6HF(g) 
3(g)  + 5F2(g)  → N2F4(g)  + 6HF(g)    A) 179.1 kJ B) −179.1 kJ C) 1539.7 kJ D) −1539.7 kJ E) None of these choices are correct." class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  179.1 kJ
B)  −179.1 kJ
C)  1539.7 kJ
D)  −1539.7 kJ
E)  None of these choices are correct.F) A) and E)
G) B) and C)

Question 5

Select the correct statement of a law of thermodynamics.

Accepted Answer

A)  The enthalpy of the universe is constantly increasing.
B)  The entropy of the universe is constant.
C)  The entropy of an element in its standard state at 25°C is zero.
D)  Every spontaneous process is accompanied by an increase in total entropy.
E)  Every spontaneous process is accompanied by a decrease in the enthalpy of the system.F) B) and E)
G) C) and D)

Question 6

Use the thermodynamic data at 298 K below to determine the Ksp for barium carbonate, BaCO3 at this temperature. sp for barium carbonate, BaCO3 at this temperature.   A) 5.86 B) 6.30 × 10 8 C) 1.59 × 10 −9 D) 5.47 × 10 −21 E) 2.18 × 10 −27" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  5.86
B)  6.30 × 10 8
C)  1.59 × 10 −9
D)  5.47 × 10 −21
E)  2.18 × 10 −27F) None of the above
G) B) and D)

Question 7

Elemental boron can be formed by reaction of boron trichloride with hydrogen. BCl3(g)  + 1.5H2(g)  → B(s)  + 3HCl(g) 
3(g)  + 1.5H2(g)  → B(s)  + 3HCl(g)    If ΔS° = 80.3 J/K for the reaction above, what is S° for BCl3(g) ? A) −18.2 J/K·mol B) 18.2 J/K·mol C) 290.1 J/K·mol D) 355.4 J/K.mol E) 450.6 J/K·mol" class="answers-bank-image d-inline" rel="preload" > If ΔS° = 80.3 J/K for the reaction above, what is S° for BCl3(g) ?

Accepted Answer

A)  −18.2 J/K·mol
B)  18.2 J/K·mol
C)  290.1 J/K·mol
D)  355.4 J/K.mol
E)  450.6 J/K·molF) A) and E)
G) A) and B)

Question 8

The entropy of one mole of oxygen gas in a 0.5-L container is less than it would be in a 22.4-L container at the same temperature.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following is always true for an exothermic process?

Accepted Answer

A)  q sys > 0, Δ S surr 
B)  q sys surr > 0
C)  q sys surr 
D)  q sys > 0, Δ S surr > 0
E)  w < 0F) All of the above
G) B) and C)

Question 10

The temperature at which the following process reaches equilibrium at 1.0 atm is the normal boiling point of hydrogen peroxide. H2O2(l)  ⇄ H2O2(g) 
Use the following thermodynamic information at 298 K to determine this temperature.
2O2(l)  ⇄ H2O2(g)  Use the following thermodynamic information at 298 K to determine this temperature.   A) 120°C B) 144°C C) 196°C D) 418°C E) 585°C" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  120°C
B)  144°C
C)  196°C
D)  418°C
E)  585°CF) D) and E)
G) B) and D)

Question 11

In a spontaneous process, the entropy of the system always increases.

Accepted Answer

A) True 
 B)False

Question 12

In order for a process to be spontaneous,

Accepted Answer

A)  the entropy of the system must increase.
B)  the entropy of the surroundings must increase.
C)  the entropy of the universe must decrease.
D)  the entropy of the surroundings must decrease.
E)  the entropy change of the surroundings plus the entropy change of the system must be positive.F) A) and D)
G) B) and C)

Question 13

In some spontaneous processes, the entropy of the surroundings decreases.

Accepted Answer

A) True 
 B)False

Question 14

Use the given data at 298 K to calculate ΔG° for the reaction 2Cl2(g)  + SO2(g)  → SOCl2(g)  + Cl2O(g) 
2(g)  + SO2(g)  → SOCl2(g)  + Cl2O(g)    A) 129.3 kJ B) 133.6 kJ C) 196.0 kJ D) 199.8 kJ E) 229.6 kJ" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  129.3 kJ
B)  133.6 kJ
C)  196.0 kJ
D)  199.8 kJ
E)  229.6 kJF) A) and C)
G) B) and E)

Question 15

For a process with ΔS < 0, which one of the following statements is correct?

Accepted Answer

A)  The process will definitely be spontaneous if ΔH 
B)  The process will be definitely be spontaneous if Δ H 
C)  The process can never be spontaneous.
D)  The process will definitely be spontaneous, regardless of Δ H.
E)  The process will definitely be spontaneous if Δ S surr > 0.F) C) and D)
G) A) and C)

Question 16

When a sky diver free-falls through the air, the process is

Accepted Answer

A)  non-spontaneous because he is accelerating due to the force applied by gravity.
B)  non-spontaneous because he is losing potential energy.
C)  non-spontaneous, if he had planned the jump for two weeks.
D)  spontaneous.
E)  in equilibrium.F) D) and E)
G) A) and C)

Question 17

Which relationship best describes ΔS° for the following reaction? CO(g)  + H2O(g)  → CO2(g)  + H2(g)

Accepted Answer

A)  Δ S° = Δ H°
B)  Δ S° = Δ H°/ T
C)  Δ S° > 0
D)  Δ S° 
E)  Δ S° ≈ 0F) A) and C)
G) A) and E)

Question 18

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25°C.

Accepted Answer

A)  CO( g) , CO 2( g) 
B)  NaCl( s) , NaCl( aq) 
C)  H 2S( g) , H 2S( aq) 
D)  Li( s) , Pb( s) 
E)  H 2( g) , H 2O( g) F) A) and E)
G) None of the above

Question 19

Given: H2O(l)  → H2O(g)  ΔH° = 40.7 kJ at 373K What is the entropy change in the system (ΔS)  when one mole of water vaporizes at 100°C and a pressure of one atmosphere?

Accepted Answer

A)  407 J/K
B)  −407 J/K
C)  109 J/K
D)  −109 J/K
E)  J/KF) B) and E)
G) A) and E)

Question 20

A certain process has ΔSuniv > 0 at 25°C. What does one know about the process?

Accepted Answer

A)  It is exothermic.
B)  It is endothermic.
C)  It is spontaneous at 25°C.
D)  It will move rapidly toward equilibrium.
E)  None of these choices are correct.F) A) and C)
G) D) and E)

Exam 20: Thermodynamics: Entropy, Free Energy, and Reaction Direction

The reaction of methane with water to form carbon dioxide and hydrogen is nonspontaneous at 298 K. At what temperature will this system make the transition from nonspontaneous to spontaneous? The data refer to 298 K. CH4(g) + 2H2O(g) ⇄ CO2(g) + 4H2(g)

Correct AnswerverifiedShow Answer

For a given reaction, a change in the pressure may result in a change in the sign of ΔG.

Correct AnswerverifiedShow Answer

In some spontaneous processes, the entropy of the surroundings decreases.

Correct AnswerverifiedShow Answer

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25°C.

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Which of the following is always true for an exothermic process?

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For a process with ΔS < 0, which one of the following statements is correct?

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Given: H2O(l) → H2O(g) ΔH° = 40.7 kJ at 373K What is the entropy change in the system (ΔS) when one mole of water vaporizes at 100°C and a pressure of one atmosphere?

Correct AnswerverifiedShow Answer

In order for a process to be spontaneous,

Correct AnswerverifiedShow Answer

Calculate ΔG° for the reaction of ammonia with fluorine. 2NH3(g) + 5F2(g) → N2F4(g) + 6HF(g)

Correct AnswerverifiedShow Answer

Use the thermodynamic data at 298 K below to determine the Ksp for barium carbonate, BaCO3 at this temperature.

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Use the given data at 298 K to calculate ΔG° for the reaction 2Cl2(g) + SO2(g) → SOCl2(g) + Cl2O(g)

Correct AnswerverifiedShow Answer

The entropy of one mole of oxygen gas in a 0.5-L container is less than it would be in a 22.4-L container at the same temperature.

Correct AnswerverifiedShow Answer

The temperature at which the following process reaches equilibrium at 1.0 atm is the normal boiling point of hydrogen peroxide. H2O2(l) ⇄ H2O2(g) Use the following thermodynamic information at 298 K to determine this temperature.

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When a sky diver free-falls through the air, the process is

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In a spontaneous process, the entropy of the system always increases.

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A certain process has ΔSuniv > 0 at 25°C. What does one know about the process?

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In order for a process to be spontaneous,

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Select the correct statement of a law of thermodynamics.

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Which relationship best describes ΔS° for the following reaction? CO(g) + H2O(g) → CO2(g) + H2(g)

Correct AnswerverifiedShow Answer

Elemental boron can be formed by reaction of boron trichloride with hydrogen. BCl3(g) + 1.5H2(g) → B(s) + 3HCl(g) If ΔS° = 80.3 J/K for the reaction above, what is S° for BCl3(g) ?

Correct AnswerverifiedShow Answer

The reaction of methane with water to form carbon dioxide and hydrogen is nonspontaneous at 298 K. At what temperature will this system make the transition from nonspontaneous to spontaneous? The data refer to 298 K. CH₄(g) + 2H₂O(g) ⇄ CO₂(g) + 4H₂(g)

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Given: H₂O(l) → H₂O(g) ΔH° = 40.7 kJ at 373K What is the entropy change in the system (ΔS) when one mole of water vaporizes at 100°C and a pressure of one atmosphere?

Correct Answer
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Correct Answer
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Calculate ΔG° for the reaction of ammonia with fluorine. 2NH₃(g) + 5F₂(g) → N₂F₄(g) + 6HF(g)

Correct Answer
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Use the thermodynamic data at 298 K below to determine the K_sp for barium carbonate, BaCO₃ at this temperature.

Correct Answer
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Use the given data at 298 K to calculate ΔG° for the reaction 2Cl₂(g) + SO₂(g) → SOCl₂(g) + Cl₂O(g)

Correct Answer
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The temperature at which the following process reaches equilibrium at 1.0 atm is the normal boiling point of hydrogen peroxide. H₂O₂(l) ⇄ H₂O₂(g) Use the following thermodynamic information at 298 K to determine this temperature.

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A certain process has ΔS_univ > 0 at 25°C. What does one know about the process?

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Which relationship best describes ΔS° for the following reaction? CO(g) + H₂O(g) → CO₂(g) + H₂(g)

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Elemental boron can be formed by reaction of boron trichloride with hydrogen. BCl₃(g) + 1.5H₂(g) → B(s) + 3HCl(g) If ΔS° = 80.3 J/K for the reaction above, what is S° for BCl₃(g) ?

Correct Answer
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