Question 1

Elemental boron can be formed by reaction of boron trichloride with hydrogen.
BCl3(g) + 1.5H2(g)   →	o→  B(s) + 3HCl(g) 
Calculate  Δ\DeltaΔ G° for the reaction.
3(g) + 1.5H2(g)   	o  B(s) + 3HCl(g)  Calculate  \Delta G° for the reaction.   A) -293.4 kJ B) 293.4 kJ C) -102.8 kJ D) 102.8 kJ E) None of these choices is correct. " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  -293.4 kJ
B)  293.4 kJ
C)  -102.8 kJ
D)  102.8 kJ
E)  None of these choices is correct.

Question 2

Calculate  Δ\DeltaΔ S° for the reaction
4Cr(s) + 3O2(g)  →	o→  2Cr2O3(s) 
2(g)  	o  2Cr2O3(s)    A) -548.1 J/K B) -147.7 J/K C) 147.7 J/K D) 310.1 J/K E) 548.1 J/K " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  -548.1 J/K
B)  -147.7 J/K
C)  147.7 J/K
D)  310.1 J/K
E)  548.1 J/K

Question 3

In tables of thermodynamic data provided in chemistry books,one finds $\Delta$H° f ,$\Delta$G° f and S° listed.Briefly,explain why the entropy data are supplied as S°,while the enthalpy and free energy data are in the form of $\Delta$H° f and $\Delta$G° f,respectively.

Accepted Answer

The third law specifies the state of zer...

Question 4

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) ,CO2(g) 
B)  NaCl(s) ,NaCl(aq) 
C)  H2S(g) ,H2S(aq) 
D)  Li(s) ,Pb(s) 
E)  H2(g) ,H2O(g)  C

Question 5

Which relationship or statement best describes  Δ\DeltaΔ S° for the following reaction?
2H2S(g) + 3O2(g)   →	o→ 2H2O(g) + 2SO2(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.

Question 6

A certain process has  Δ\DeltaΔ Suniv > 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 is correct.

Question 7

Calculate  Δ\DeltaΔ S° for the reaction
SiCl4(g) + 2Mg(s)   →	o→  2MgCl2(s) + Si(s) 
4(g) + 2Mg(s)   	o  2MgCl2(s) + Si(s)    A) -254.96 J/K B) -198.02 J/K C) 198.02 J/K D) 254.96 J/K E) 471.86 J/K " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  -254.96 J/K
B)  -198.02 J/K
C)  198.02 J/K
D)  254.96 J/K
E)  471.86 J/K  B

Question 8

Which relationship or statement best describes  Δ\DeltaΔ S° for the following reaction?
Pb(s) + Cl2(g)   →	o→  PbCl2(s)

Accepted Answer

A)  ( Δ\DeltaΔ S° ≈\approx≈  00
B)  9 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.

Question 9

Which relationship or statement best describes  Δ\DeltaΔ S° for the following reaction?
K2SO4(s)   →	o→  2K+(aq) + SO42-(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.

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)  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" >
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°C B

Question 11

Which,if any,of the following processes is spontaneous under the specified conditions?

Accepted Answer

A)  H2O(l)   →	o→ H2O(s) at 25°C
B)  CO2(s)   →	o→  CO2(g) at 0°C
C)  2H2O(g)   →	o→ 2H2(g) + O2(g) 
D)  C(graphite)   →	o→  C(diamond) at 25°C and 1 atm pressure
E)  None of these is spontaneous.

Question 12

Photosynthesis can be represented by the equation
6CO2(g)+ 6H2O(l) $\to$C6H12O6(s)+ 6O2(g)
a.Calculate $\Delta$S° for this process,given the following data:
  
b.Given that $\Delta$H° for the reaction is 2802 kJ,calculate $\Delta$G° at 25°C.

Accepted Answer

a.<img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30">S° = -26...

Question 13

Sulfuryl dichloride is formed when sulfur dioxide reacts with chlorine.The data refer to 298 K.
SO2(g) + Cl2(g)   →	o→  SO2Cl2(g) 
2(g) + Cl2(g)   	o  SO2Cl2(g)    What is the value of  \Delta G° for this reaction at 600 K? A) -162.8 kJ B) -40.1 kJ C) -28.4 kJ D) 28.4 kJ E) 162.8 kJ " class="answers-bank-image d-inline" rel="preload" >
What is the value of  Δ\DeltaΔ G° for this reaction at 600 K?

Accepted Answer

A)  -162.8 kJ
B)  -40.1 kJ
C)  -28.4 kJ
D)  28.4 kJ
E)  162.8 kJ

Question 14

Consider the figure below which shows  Δ\DeltaΔ G° for a chemical process plotted against absolute temperature.Which one of the following is an incorrect conclusion,based on the information in the diagram?  0)  B) ( \Delta S° > 0)  C) The reaction is spontaneous at high temperatures. D) ( \Delta S° increases with temperature while  \Delta H° remains constant.)  E) (There exists a certain temperature at which  \Delta H° = T \Delta S°.)  " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  ( Δ\DeltaΔ H° > 0) 
B)  ( Δ\DeltaΔ S° > 0) 
C)  The reaction is spontaneous at high temperatures.
D)  ( Δ\DeltaΔ S° increases with temperature while  Δ\DeltaΔ H° remains constant.) 
E)  (There exists a certain temperature at which  Δ\DeltaΔ H° = T Δ\DeltaΔ S°.)

Question 15

For a reaction at equilibrium,$\Delta$Suniv = 0.

Accepted Answer

A) True 
 B)False

Question 16

Which of the following is necessary for a process to be spontaneous?

Accepted Answer

A)  ( Δ\DeltaΔ Hsys 
B)  ( Δ\DeltaΔ Ssys > 0) 
C)  ( Δ\DeltaΔ Ssurr 
D)  ( Δ\DeltaΔ Suniv > 0) 
E)  ( Δ\DeltaΔ Gsys = 0)

Question 17

The water-gas shift reaction plays an important role in the production of clean fuel from coal.
CO(g)+ H2O(g)  
CO2(g)+ H2(g)
Use the following thermodynamic data to determine the equilibrium constant Kp at 700.K.

Accepted Answer

Question 18

The free energy of a perfect crystal at absolute zero,is zero.

Accepted Answer

A) True 
 B)False

Question 19

Which relationship or statement best describes  Δ\DeltaΔ S° for the following reaction?
HgS(s) + O2(g)  →	o→  Hg(l) + SO2(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.

Question 20

Consider the figure below which shows  Δ\DeltaΔ G° for a chemical process plotted against absolute temperature.From this plot,it is reasonable to conclude that:  0, \Delta S° > 0)  B) ( \Delta H° > 0, \Delta S°  0)  D) ( \Delta H°

Accepted Answer

A)  ( Δ\DeltaΔ H° > 0, Δ\DeltaΔ S° > 0) 
B)  ( Δ\DeltaΔ H° > 0, Δ\DeltaΔ S° 
C)  ( Δ\DeltaΔ H° Δ\DeltaΔ S° > 0) 
D)  ( Δ\DeltaΔ H° Δ\DeltaΔ S° 
E)  None of these choices is correct.

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

Correct Answer
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Calculate $\Delta$ S° for the reaction 4Cr(s) + 3O₂(g) $\to$ 2Cr₂O₃(s) $Calculate \Delta S° for the reaction 4Cr(s) + 3O<sub>2</sub>(g) \to 2Cr<sub>2</sub>O<sub>3</sub>(s) A) -548.1 J/K B) -147.7 J/K C) 147.7 J/K D) 310.1 J/K E) 548.1 J/K$

Correct Answer
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In tables of thermodynamic data provided in chemistry books,one finds $\Delta$ H° _f , $\Delta$ G° _f and S° listed.Briefly,explain why the entropy data are supplied as S°,while the enthalpy and free energy data are in the form of $\Delta$ H° _f and $\Delta$ G° _f,respectively.

Correct Answer
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The third law specifies the state of zer...
View Answer

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

Correct Answer
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C

Which relationship or statement best describes $\Delta$ S° for the following reaction? 2H₂S(g) + 3O₂(g) $\to$ 2H₂O(g) + 2SO₂(g)

Correct Answer
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A certain process has $\Delta$ S_univ > 0 at 25°C.What does one know about the process?

Correct Answer
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Calculate $\Delta$ S° for the reaction SiCl₄(g) + 2Mg(s) $\to$ 2MgCl₂(s) + Si(s) $Calculate \Delta S° for the reaction SiCl<sub>4</sub>(g) + 2Mg(s) \to 2MgCl<sub>2</sub>(s) + Si(s) A) -254.96 J/K B) -198.02 J/K C) 198.02 J/K D) 254.96 J/K E) 471.86 J/K$

Correct Answer
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B

Which relationship or statement best describes $\Delta$ S° for the following reaction? Pb(s) + Cl₂(g) $\to$ PbCl₂(s)

Correct Answer
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Which relationship or statement best describes $\Delta$ S° for the following reaction? K₂SO₄(s) $\to$ 2K⁺(aq) + SO₄^2-(aq)

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.

Correct Answer
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B

Which,if any,of the following processes is spontaneous under the specified conditions?

Correct Answer
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Correct Answer
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a.S° = -26...
View Answer

Correct Answer
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Correct Answer
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For a reaction at equilibrium, $\Delta$ S_univ = 0.

Correct Answer
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Which of the following is necessary for a process to be spontaneous?

Correct Answer
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The water-gas shift reaction plays an important role in the production of clean fuel from coal. CO(g)+ H₂O(g) CO₂(g)+ H₂(g) Use the following thermodynamic data to determine the equilibrium constant K_p at 700.K.

Correct Answer
verified

The free energy of a perfect crystal at absolute zero,is zero.

Correct Answer
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Which relationship or statement best describes $\Delta$ S° for the following reaction? HgS(s) + O₂(g) $\to$ Hg(l) + SO₂(g)

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

Elemental boron can be formed by reaction of boron trichloride with hydrogen. BCl3(g) + 1.5H2(g) →\to→ B(s) + 3HCl(g) Calculate Δ\DeltaΔ G° for the reaction.

Correct AnswerverifiedShow Answer

Calculate Δ\DeltaΔ S° for the reaction 4Cr(s) + 3O2(g) →\to→ 2Cr2O3(s)

Correct AnswerverifiedShow Answer

In tables of thermodynamic data provided in chemistry books,one finds Δ\DeltaΔ H° f , Δ\DeltaΔ G° f and S° listed.Briefly,explain why the entropy data are supplied as S°,while the enthalpy and free energy data are in the form of Δ\DeltaΔ H° f and Δ\DeltaΔ G° f,respectively.

Correct AnswerverifiedThe third law specifies the state of zer...View AnswerShow Answer

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

Correct AnswerverifiedC

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? 2H2S(g) + 3O2(g) →\to→ 2H2O(g) + 2SO2(g)

Correct AnswerverifiedShow Answer

A certain process has Δ\DeltaΔ Suniv > 0 at 25°C.What does one know about the process?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedB

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? Pb(s) + Cl2(g) →\to→ PbCl2(s)

Correct AnswerverifiedShow Answer

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? K2SO4(s) →\to→ 2K+(aq) + SO42-(aq)

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.

Correct AnswerverifiedB

Which,if any,of the following processes is spontaneous under the specified conditions?

Correct AnswerverifiedShow Answer

Photosynthesis can be represented by the equation 6CO2(g)+ 6H2O(l) →\to→ C6H12O6(s)+ 6O2(g) a.Calculate Δ\DeltaΔ S° for this process,given the following data: b.Given that Δ\DeltaΔ H° for the reaction is 2802 kJ,calculate Δ\DeltaΔ G° at 25°C.

Correct Answerverifieda.S° = -26...View AnswerShow Answer

Sulfuryl dichloride is formed when sulfur dioxide reacts with chlorine.The data refer to 298 K. SO2(g) + Cl2(g) →\to→ SO2Cl2(g) What is the value of Δ\DeltaΔ G° for this reaction at 600 K?

Correct AnswerverifiedShow Answer

Consider the figure below which shows Δ\DeltaΔ G° for a chemical process plotted against absolute temperature.Which one of the following is an incorrect conclusion,based on the information in the diagram?

Correct AnswerverifiedShow Answer

For a reaction at equilibrium, Δ\DeltaΔ Suniv = 0.

Correct AnswerverifiedShow Answer

Which of the following is necessary for a process to be spontaneous?

Correct AnswerverifiedShow Answer

The water-gas shift reaction plays an important role in the production of clean fuel from coal. CO(g)+ H2O(g) CO2(g)+ H2(g) Use the following thermodynamic data to determine the equilibrium constant Kp at 700.K.

Correct AnswerverifiedShow Answer

The free energy of a perfect crystal at absolute zero,is zero.

Correct AnswerverifiedShow Answer

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? HgS(s) + O2(g) →\to→ Hg(l) + SO2(g)

Correct AnswerverifiedShow Answer

Consider the figure below which shows Δ\DeltaΔ G° for a chemical process plotted against absolute temperature.From this plot,it is reasonable to conclude that:

Correct AnswerverifiedShow Answer

Correct Answer
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Calculate $\Delta$ S° for the reaction 4Cr(s) + 3O₂(g) $\to$ 2Cr₂O₃(s) $Calculate \Delta S° for the reaction 4Cr(s) + 3O<sub>2</sub>(g) \to 2Cr<sub>2</sub>O<sub>3</sub>(s) A) -548.1 J/K B) -147.7 J/K C) 147.7 J/K D) 310.1 J/K E) 548.1 J/K$

Correct Answer
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In tables of thermodynamic data provided in chemistry books,one finds $\Delta$ H° _f , $\Delta$ G° _f and S° listed.Briefly,explain why the entropy data are supplied as S°,while the enthalpy and free energy data are in the form of $\Delta$ H° _f and $\Delta$ G° _f,respectively.

Correct Answer
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The third law specifies the state of zer...
View Answer

Correct Answer
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C

Which relationship or statement best describes $\Delta$ S° for the following reaction? 2H₂S(g) + 3O₂(g) $\to$ 2H₂O(g) + 2SO₂(g)

Correct Answer
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A certain process has $\Delta$ S_univ > 0 at 25°C.What does one know about the process?

Correct Answer
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Calculate $\Delta$ S° for the reaction SiCl₄(g) + 2Mg(s) $\to$ 2MgCl₂(s) + Si(s) $Calculate \Delta S° for the reaction SiCl<sub>4</sub>(g) + 2Mg(s) \to 2MgCl<sub>2</sub>(s) + Si(s) A) -254.96 J/K B) -198.02 J/K C) 198.02 J/K D) 254.96 J/K E) 471.86 J/K$

Correct Answer
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B

Which relationship or statement best describes $\Delta$ S° for the following reaction? Pb(s) + Cl₂(g) $\to$ PbCl₂(s)

Correct Answer
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Which relationship or statement best describes $\Delta$ S° for the following reaction? K₂SO₄(s) $\to$ 2K⁺(aq) + SO₄^2-(aq)

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.

Correct Answer
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B

Correct Answer
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Correct Answer
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a.S° = -26...
View Answer

Correct Answer
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Correct Answer
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For a reaction at equilibrium, $\Delta$ S_univ = 0.

Correct Answer
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Correct Answer
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The water-gas shift reaction plays an important role in the production of clean fuel from coal. CO(g)+ H₂O(g) CO₂(g)+ H₂(g) Use the following thermodynamic data to determine the equilibrium constant K_p at 700.K.

Correct Answer
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Correct Answer
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Which relationship or statement best describes $\Delta$ S° for the following reaction? HgS(s) + O₂(g) $\to$ Hg(l) + SO₂(g)

Correct Answer
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Correct Answer
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