Question 1

In which one of these pairs will the entropy of the first substance be greater than that of the second? Assume P and T are the same for each pair,unless stated otherwise.

Accepted Answer

A)  1 mole of F2(g) ;1 mole of Cl2(g) 
B)  1 mole of I2(s) ;1 mole of I2(g) 
C)  1 mole of CaCO3(s) ;1 mole of CaO(s) plus 1 mole of CO2(g) 
D)  1 mole of H2(g) at 25°C;1 mole of H2(g) at 50°C
E)  1 mole of O3(g) ;1 mole of O2(g) F) A) and B)
G) A) and C)

Question 2

Which relationship or statement best describes  Δ\DeltaΔ S° for the following reaction?
CaO(s) + CO2(g)   →	o→  CaCO3(s)

Accepted Answer

A)  ( Δ\DeltaΔ S°  ≈\approx≈  0) 
B)  ( Δ\DeltaΔ S° 
C)  ( Δ\DeltaΔ S° > 0) 
D)  ( Δ\DeltaΔ S° =  Δ\DeltaΔ H°/T) 
E)  More information is needed to make a reasonable prediction. F) A) and B)
G) C) and D)

Question 3

Which of the following should have the greatest molar entropy at 298 K?

Accepted Answer

A)  CH4(g) 
B)  H2O(l) 
C)  NaCl(s) 
D)  N2O4(g) 
E)  H2(g) F) A) and D)
G) All of the above

Question 4

In order for a process to be spontaneous,

Accepted Answer

A)  ( Δ\DeltaΔ H must be less than zero.) 
B)  ( Δ\DeltaΔ S must be greater than zero.) 
C)  ( Δ\DeltaΔ G must be greater than zero.) 
D)  it should be rapid.
E)  ( Δ\DeltaΔ Ssys +  Δ\DeltaΔ Ssurr must be greater than zero.)  F) All of the above
G) B) and E)

Question 5

A reaction has a positive value of $\Delta$H° and a positive value of $\Delta$S°.
Draw a neat,labeled schematic plot to show how $\Delta$G° (y-axis)will depend on absolute temperature (x-axis).

Accepted Answer

The answer of A reaction has a positive value of...

Question 6

Which relationship best describes  Δ\DeltaΔ S° for the following reaction?
8H2(g) + S8(s)   →	o→  8H2S(g)

Accepted Answer

A)  9 Δ\DeltaΔ S° =  Δ\DeltaΔ H°) 
B)  ( Δ\DeltaΔ S° =  Δ\DeltaΔ H°/T) 
C)  ( Δ\DeltaΔ S°  ≈\approx≈  ) 
D)  ( Δ\DeltaΔ S° 
E)  ( Δ\DeltaΔ S° > 0)  F) None of the above
G) B) and C)

Question 7

For any reaction,if $\Delta$G° > 0,then K < 1.

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

Which relationship or statement best describes  Δ\DeltaΔ S° for the following reaction?
BaCl2(aq) + Na2SO4(aq)   →	o→  BaSO4(s) + 2NaCl(aq)

Accepted Answer

A)  ( Δ\DeltaΔ S°  ≈\approx≈  0) 
B)  ( Δ\DeltaΔ S° 
C)  ( Δ\DeltaΔ S° > 0) 
D)  ( Δ\DeltaΔ S° =  Δ\DeltaΔ H°/T) 
E)  More information is needed to make a reasonable prediction. F) C) and E)
G) C) and D)

Question 10

As a chemical reaction proceeds toward equilibrium,the free energy of the system decreases.

Accepted Answer

A) True 
 B)False

Question 11

Compare one mole of ice with one mole of liquid water,both at 1.0 atm and 0°C.The melting point of ice at 1.0 atm is 0°C.For the process
H2O(s) $\to$ H2O(l)
under these conditions predict whether each of the following quantities will be greater than,less than,or equal to,zero .Explain each prediction in one sentence.
a.$\Delta$H°
b.$\Delta$S°
c.$\Delta$G°

Accepted Answer

a.<img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30">H° > 0.The solid-to-liquid phase chang...

Question 12

Calculate  Δ\DeltaΔ G° for the reaction
SiCl4(g) + 2Mg(s)   →	o→  2MgCl2(s) + Si(s) 
4(g) + 2Mg(s)   	o  2MgCl2(s) + Si(s)    A) 566.60 kJ B) 50.38 kJ C) 25.19 kJ D) -25.19 kJ E) -566.60 kJ " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  566.60 kJ
B)  50.38 kJ
C)  25.19 kJ
D)  -25.19 kJ
E)  -566.60 kJ F) C) and D)
G) B) and C)

Question 13

Calculate the equilibrium constant at 25°C for the reaction of methane with water to form carbon dioxide and hydrogen.The data refer to 25°C.
CH4(g) + 2H2O(g)  4(g) + 2H2O(g)    CO2(g) + 4H2(g)    A) 8.2  	imes  1019 B) 0.96 C) 0.58 D) 1.2  	imes  10-20 E) 1.4  	imes  10-46 " class="answers-bank-image d-inline" rel="preload" >
CO2(g) + 4H2(g) 
4(g) + 2H2O(g)    CO2(g) + 4H2(g)    A) 8.2  	imes  1019 B) 0.96 C) 0.58 D) 1.2  	imes  10-20 E) 1.4  	imes  10-46 " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  8.2  ×	imes×  1019
B)  0.96
C)  0.58
D)  1.2  ×	imes×  10-20
E)  1.4  ×	imes×  10-46 F) C) and D)
G) A) and B)

Question 14

For a process with  Δ\DeltaΔ S < 0,which one of the following statements is correct?

Accepted Answer

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

Question 15

For a chemical reaction to be non-spontaneous at any temperature,which of the following conditions must be met?

Accepted Answer

A)  ( Δ\DeltaΔ S° > 0, Δ\DeltaΔ H° > 0) 
B)  ( Δ\DeltaΔ S° > 0, Δ\DeltaΔ H° 
C)  ( Δ\DeltaΔ S° Δ\DeltaΔ H° 
D)  ( Δ\DeltaΔ S° Δ\DeltaΔ H° > 0) 
E)  (All reactions are spontaneous at some temperature. F) A) and C)
G) A) and E)

Question 16

Which relationship or statement best describes  Δ\DeltaΔ S° for the following reaction?
O3(g) + NO(g)   →	o→  O2(g) + NO2(g)

Accepted Answer

A)  ( Δ\DeltaΔ S°  ≈\approx≈  0) 
B)  ( Δ\DeltaΔ S° 
C)  ( Δ\DeltaΔ S° > 0) 
D)  ( Δ\DeltaΔ S° =  Δ\DeltaΔ H°/T) 
E)  More information is needed to make a reasonable prediction. F) A) and B)
G) A) and C)

Question 17

Consider the following quantities used in thermodynamics: E,H,q,w,S,G.How many of them are state functions?

Accepted Answer

A)  0
B)  1
C)  2
D)  3
E)  4F) A) and B)
G) C) and D)

Question 18

You are given pure samples of ethane,C2H6(g) ,and toluene,C7H8(l) .What prediction would you make concerning their standard molar entropies at 298 K?

Accepted Answer

A)  S°ethane > S°toluene
B)  S°ethane toluene
C)  S°ethane  ≈\approx≈   (S°toluene)   ÷\div÷   3
D)  S°ethane  ≈\approx≈  S°toluene
E)  Since toluene is much more complex than ethane,but ethane is in the gas phase while toluene is a liquid,none of these predictions can be confidently made without further information or calculations. F) A) and D)
G) A) and C)

Question 19

Which of the following is true for a system at equilibrium?

Accepted Answer

A)  ( Δ\DeltaΔ S°sys =  Δ\DeltaΔ S°surr) 
B)  ( Δ\DeltaΔ S°sys = - Δ\DeltaΔ S°surr) 
C)  ( Δ\DeltaΔ S°sys =  Δ\DeltaΔ S°surr = 0) 
D)  ( Δ\DeltaΔ S°univ > 0) 
E)  (None of these is a sufficient condition. F) D) and E)
G) None of the above

Question 20

The higher the pressure of a gas sample,the greater is its entropy.

Accepted Answer

A) True 
 B)False

Exam 20: Thermodynamics: Entropy, free Energy, and the Direction of Chemical Reactions

Which of the following should have the greatest molar entropy at 298 K?

Correct Answer
verified

Correct Answer
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a.H° > 0.The solid-to-liquid phase chang...
View Answer

Which relationship or statement best describes $\Delta$ S° for the following reaction? CaO(s) + CO₂(g) $\to$ CaCO₃(s)

Correct Answer
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Which relationship or statement best describes $\Delta$ S° for the following reaction? BaCl₂(aq) + Na₂SO₄(aq) $\to$ BaSO₄(s) + 2NaCl(aq)

Correct Answer
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For a chemical reaction to be non-spontaneous at any temperature,which of the following conditions must be met?

Correct Answer
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For a process with $\Delta$ S < 0,which one of the following statements is correct?

Correct Answer
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The higher the pressure of a gas sample,the greater is its entropy.

Correct Answer
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A reaction has a positive value of $\Delta$ H° and a positive value of $\Delta$ S°. Draw a neat,labeled schematic plot to show how $\Delta$ G° (y-axis)will depend on absolute temperature (x-axis).

Correct Answer
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Correct Answer
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Which relationship best describes $\Delta$ S° for the following reaction? 8H₂(g) + S₈(s) $\to$ 8H₂S(g)

Correct Answer
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As a chemical reaction proceeds toward equilibrium,the free energy of the system decreases.

Correct Answer
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In which one of these pairs will the entropy of the first substance be greater than that of the second? Assume P and T are the same for each pair,unless stated otherwise.

Correct Answer
verified

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

Correct Answer
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You are given pure samples of ethane,C₂H₆(g) ,and toluene,C₇H₈(l) .What prediction would you make concerning their standard molar entropies at 298 K?

Correct Answer
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Calculate $\Delta$ G° for the reaction SiCl₄(g) + 2Mg(s) $\to$ 2MgCl₂(s) + Si(s) $Calculate \Delta G° for the reaction SiCl<sub>4</sub>(g) + 2Mg(s) \to 2MgCl<sub>2</sub>(s) + Si(s) A) 566.60 kJ B) 50.38 kJ C) 25.19 kJ D) -25.19 kJ E) -566.60 kJ$

Correct Answer
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Which relationship or statement best describes $\Delta$ S° for the following reaction? O₃(g) + NO(g) $\to$ O₂(g) + NO₂(g)

Correct Answer
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Which of the following is true for a system at equilibrium?

Correct Answer
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In order for a process to be spontaneous,

Correct Answer
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Consider the following quantities used in thermodynamics: E,H,q,w,S,G.How many of them are state functions?

Correct Answer
verified

For any reaction,if $\Delta$ G° > 0,then K < 1.

Correct Answer
verified

Exam 20: Thermodynamics: Entropy, free Energy, and the Direction of Chemical Reactions

Which of the following should have the greatest molar entropy at 298 K?

Correct AnswerverifiedShow Answer

Correct Answerverifieda.H° > 0.The solid-to-liquid phase chang...View AnswerShow Answer

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? CaO(s) + CO2(g) →\to→ CaCO3(s)

Correct AnswerverifiedShow Answer

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? BaCl2(aq) + Na2SO4(aq) →\to→ BaSO4(s) + 2NaCl(aq)

Correct AnswerverifiedShow Answer

For a chemical reaction to be non-spontaneous at any temperature,which of the following conditions must be met?

Correct AnswerverifiedShow Answer

For a process with Δ\DeltaΔ S < 0,which one of the following statements is correct?

Correct AnswerverifiedShow Answer

The higher the pressure of a gas sample,the greater is its entropy.

Correct AnswerverifiedShow Answer

A reaction has a positive value of Δ\DeltaΔ H° and a positive value of Δ\DeltaΔ S°. Draw a neat,labeled schematic plot to show how Δ\DeltaΔ G° (y-axis)will depend on absolute temperature (x-axis).

Correct AnswerverifiedShow Answer

Calculate the equilibrium constant at 25°C for the reaction of methane with water to form carbon dioxide and hydrogen.The data refer to 25°C. CH4(g) + 2H2O(g) CO2(g) + 4H2(g)

Correct AnswerverifiedShow Answer

Which relationship best describes Δ\DeltaΔ S° for the following reaction? 8H2(g) + S8(s) →\to→ 8H2S(g)

Correct AnswerverifiedShow Answer

As a chemical reaction proceeds toward equilibrium,the free energy of the system decreases.

Correct AnswerverifiedShow Answer

In which one of these pairs will the entropy of the first substance be greater than that of the second? Assume P and T are the same for each pair,unless stated otherwise.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

You are given pure samples of ethane,C2H6(g) ,and toluene,C7H8(l) .What prediction would you make concerning their standard molar entropies at 298 K?

Correct AnswerverifiedShow Answer

Calculate Δ\DeltaΔ G° for the reaction SiCl4(g) + 2Mg(s) →\to→ 2MgCl2(s) + Si(s)

Correct AnswerverifiedShow Answer

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? O3(g) + NO(g) →\to→ O2(g) + NO2(g)

Correct AnswerverifiedShow Answer

Which of the following is true for a system at equilibrium?

Correct AnswerverifiedShow Answer

In order for a process to be spontaneous,

Correct AnswerverifiedShow Answer

Consider the following quantities used in thermodynamics: E,H,q,w,S,G.How many of them are state functions?

Correct AnswerverifiedShow Answer

For any reaction,if Δ\DeltaΔ G° > 0,then K < 1.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified
a.H° > 0.The solid-to-liquid phase chang...
View Answer

Which relationship or statement best describes $\Delta$ S° for the following reaction? CaO(s) + CO₂(g) $\to$ CaCO₃(s)

Correct Answer
verified

Which relationship or statement best describes $\Delta$ S° for the following reaction? BaCl₂(aq) + Na₂SO₄(aq) $\to$ BaSO₄(s) + 2NaCl(aq)

Correct Answer
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Correct Answer
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For a process with $\Delta$ S < 0,which one of the following statements is correct?

Correct Answer
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Correct Answer
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A reaction has a positive value of $\Delta$ H° and a positive value of $\Delta$ S°. Draw a neat,labeled schematic plot to show how $\Delta$ G° (y-axis)will depend on absolute temperature (x-axis).

Correct Answer
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Correct Answer
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Which relationship best describes $\Delta$ S° for the following reaction? 8H₂(g) + S₈(s) $\to$ 8H₂S(g)

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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You are given pure samples of ethane,C₂H₆(g) ,and toluene,C₇H₈(l) .What prediction would you make concerning their standard molar entropies at 298 K?

Correct Answer
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Calculate $\Delta$ G° for the reaction SiCl₄(g) + 2Mg(s) $\to$ 2MgCl₂(s) + Si(s) $Calculate \Delta G° for the reaction SiCl<sub>4</sub>(g) + 2Mg(s) \to 2MgCl<sub>2</sub>(s) + Si(s) A) 566.60 kJ B) 50.38 kJ C) 25.19 kJ D) -25.19 kJ E) -566.60 kJ$

Correct Answer
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Which relationship or statement best describes $\Delta$ S° for the following reaction? O₃(g) + NO(g) $\to$ O₂(g) + NO₂(g)

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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For any reaction,if $\Delta$ G° > 0,then K < 1.

Correct Answer
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