Question 1

The value of ΔG° at 100.0 °C for the formation of calcium chloride from its constituent elements:
Ca(s) + Cl2(g) → CaCl2(s) 
Is ________ kJ/mol.At 25.0°C for this reaction,ΔH° is -795.8 kJ/mol,ΔG° is -748.1 kJ/mol,and ΔS° is
-159.8 J/K.

Accepted Answer

A)  -855.4
B)  -736.1
C)  5.88 × 104
D)  -779.8
E)  1.52 × 104F) B) and E)
G) A) and D)

Question 2

Phosphorous and chlorine gases combine to produce phosphorous trichloride:
P2(g) + 3Cl2(g) → 2PCl3(g) 
ΔG° at 298 K for this reaction is -642.9 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P2,1.6 atm Cl2,and 0.65 atm PCl3 is ________.

Accepted Answer

A)  -44.2
B)  -3.88 × 103
C)  -7.28 × 103 
D)  -708.4
E)  -649.5F) A) and D)
G) B) and D)

Question 3

What is "free" energy? Give a fictitious example.

Accepted Answer

Consider a reaction that is exothermic (...

Question 4

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 LE) B) and C)
F) A) and B)

Question 5

Determine the equilibrium constant for the following reaction at 655 K.
HCN(g) + 2 H2(g) → CH3NH2(g) ΔH° = -158 kJ;ΔS°= -219.9 J/K

Accepted Answer

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

Question 6

Match the following.
-Q = K

Accepted Answer

A)  ΔG 
B)  standard state
C)  ΔG > 0
D)  ΔG 
E)  equilibriumF) K = 0G) ΔG > ΔG°H) All of the above
I) A) and E)

Question 7

Calculate ΔS°rxn for the following reaction.The S° for each species is shown below the reaction.
P4(g) + 10 Cl2(g) → 4 PCl5(g) 
S°(J/mol∙K) 280.0 223.1 364.6

Accepted Answer

A)  -138.5 J/K
B)  -1052.6 J/K
C)  +171.3 J/K
D)  -583.6 J/K
E)  +2334.6 J/KF) A) and C)
G) B) and C)

Question 8

Why can't we say that a spontaneous reaction is a fast reaction?

Accepted Answer

Spontaneity is a thermodynamic...

Question 9

Determine ΔG°rxn using the following information.
CaCO3(s) → CaO(s) + CO2(g) ΔH° = +179.2 kJ;ΔS° = +160.2 J/K

Accepted Answer

A)  -607.0 kJ
B)  +112 .0 kJ
C)  -89.3 kJ
D)  +131.4 kJ
E)  +228.1 kJF) C) and E)
G) B) and E)

Question 10

Calculate the ΔG°rxn using the following information.
2 HNO3(aq) + NO(g) → 3 NO2(g) + H2O(l) ΔG°rxn = ?
ΔH°f (kJ/mol) -207.0 91.3 33.2 -285.8
S°(J/mol∙K) 46.0 210.8 240.1 70.0

Accepted Answer

A)  -151 kJ
B)  -85.5 kJ
C)  +50.8 kJ
D)  +222 kJ
E)  -186 kJF) A) and E)
G) B) and E)

Question 11

Determine the equilibrium constant for the following reaction at 549 K.
CH2O(g) + 2 H2(g) → CH4(g) + H2O(g) 
ΔH° = -94.9 kJ;ΔS° = -224.2 J/K

Accepted Answer

A)  481
B)  1.07 × 109
C)  2.08 × 10-3
D)  9.35 × 10-10
E)  1.94 × 10-12F) B) and C)
G) A) and B)

Question 12

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 evaporatingF) C) and E)
G) C) and D)

Question 13

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)  ΔSuniverse is always greater than zero for a nonspontaneous process.
E)  None of the above are true.F) A) and E)
G) A) and D)

Question 14

Use Hess's law to calculate ΔG°rxn using the following information.
CO(g) → C(s) + 1/2 O2(g) ΔG°rxn = ?
CO2(g) → C(s) + O2(g) ΔG°rxn = +394.4 kJ
CO(g) + 1/2 O2(g) → CO2(g) ΔG°rxn = -257.2 kJ

Accepted Answer

A)  -60.0 kJ
B)  +651.6 kJ
C)  -265.8 kJ
D)  +137.2 kJ
E)  +523.0 kJF) A) and B)
G) C) and D)

Question 15

Which of the following relationships is correct at constant T and P?

Accepted Answer

A)  ΔG is proportional to -ΔSuniv.
B)  ΔG > 0 represents a spontaneous process.
C)  ΔG > 0 represents an increase in kinetic energy.
D)  ΔG 
E)  All of the above are correct.F) A) and B)
G) None of the above

Question 16

Estimate ΔG°rxn for the following reaction at 775 K.
2 Hg(g) + O2(g) → 2 HgO(s) ΔH° = -304.2 kJ;ΔS° = -414.2 J/K

Accepted Answer

A)  -625 kJ
B)  -181 kJ
C)  +17 kJ
D)  +321 kJ
E)  -110 kJF) A) and E)
G) A) and D)

Question 17

Which of the following processes has a ΔS < 0?

Accepted Answer

A)  Water freezes.
B)  Isopropyl alcohol condenses.
C)  methanol (g,at 555 K) → methanol (g,at 400 K) 
D)  carbon dioxide(g) → carbon dioxide(s) 
E)  All of the above processes have a ΔS < 0.F) A) and B)
G) B) and C)

Question 18

Define allotrope.

Accepted Answer

An allotrope is an e...

Question 19

Use Hess's law to calculate ΔG°rxn using the following information.
NO(g) + O(g) → NO2(g) ΔG°rxn = ?
2 O3(g) → 3 O2(g) ΔG°rxn = +489.6 kJ
O2(g) → 2 O(g) ΔG°rxn = +463.4 kJ
NO(g) + O3(g) → NO2(g) + O2(g) ΔG°rxn = -199.5 kJ

Accepted Answer

A)  +753.5 kJ
B)  +277.0 kJ
C)  -676.0 kJ
D)  -1152.5 kJ
E)  -225.7 kJF) A) and D)
G) B) and E)

Question 20

Identify the compound that is not an allotrope of carbon.

Accepted Answer

A)  diamond
B)  dry ice
C)  graphite
D)  charcoal
E)  buckyballF) All of the above
G) C) and D)

Exam 17: Free Energy and Thermodynamics

What is "free" energy? Give a fictitious example.

Correct AnswerverifiedConsider a reaction that is exothermic (...View AnswerShow Answer

Why can't we say that a spontaneous reaction is a fast reaction?

Correct AnswerverifiedSpontaneity is a thermodynamic...View AnswerShow Answer

Phosphorous and chlorine gases combine to produce phosphorous trichloride: P2(g) + 3Cl2(g) → 2PCl3(g) ΔG° at 298 K for this reaction is -642.9 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P2,1.6 atm Cl2,and 0.65 atm PCl3 is ________.

Correct AnswerverifiedShow Answer

Which of the following relationships is correct at constant T and P?

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Which of the following processes has a ΔS < 0?

Correct AnswerverifiedShow Answer

Estimate ΔG°rxn for the following reaction at 775 K. 2 Hg(g) + O2(g) → 2 HgO(s) ΔH° = -304.2 kJ;ΔS° = -414.2 J/K

Correct AnswerverifiedShow Answer

Determine ΔG°rxn using the following information. CaCO3(s) → CaO(s) + CO2(g) ΔH° = +179.2 kJ;ΔS° = +160.2 J/K

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Determine the equilibrium constant for the following reaction at 549 K. CH2O(g) + 2 H2(g) → CH4(g) + H2O(g) ΔH° = -94.9 kJ;ΔS° = -224.2 J/K

Correct AnswerverifiedShow Answer

The value of ΔG° at 100.0 °C for the formation of calcium chloride from its constituent elements: Ca(s) + Cl2(g) → CaCl2(s) Is ________ kJ/mol.At 25.0°C for this reaction,ΔH° is -795.8 kJ/mol,ΔG° is -748.1 kJ/mol,and ΔS° is -159.8 J/K.

Correct AnswerverifiedShow Answer

Calculate ΔS°rxn for the following reaction.The S° for each species is shown below the reaction. P4(g) + 10 Cl2(g) → 4 PCl5(g) S°(J/mol∙K) 280.0 223.1 364.6

Correct AnswerverifiedShow Answer

Define allotrope.

Correct AnswerverifiedAn allotrope is an e...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

Use Hess's law to calculate ΔG°rxn using the following information. NO(g) + O(g) → NO2(g) ΔG°rxn = ? 2 O3(g) → 3 O2(g) ΔG°rxn = +489.6 kJ O2(g) → 2 O(g) ΔG°rxn = +463.4 kJ NO(g) + O3(g) → NO2(g) + O2(g) ΔG°rxn = -199.5 kJ

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Identify the compound that is not an allotrope of carbon.

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Use Hess's law to calculate ΔG°rxn using the following information. CO(g) → C(s) + 1/2 O2(g) ΔG°rxn = ? CO2(g) → C(s) + O2(g) ΔG°rxn = +394.4 kJ CO(g) + 1/2 O2(g) → CO2(g) ΔG°rxn = -257.2 kJ

Correct AnswerverifiedShow Answer

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

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Match the following. -Q = K

Correct AnswerverifiedShow Answer

Which of the following statements is true?

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Calculate the ΔG°rxn using the following information. 2 HNO3(aq) + NO(g) → 3 NO2(g) + H2O(l) ΔG°rxn = ? ΔH°f (kJ/mol) -207.0 91.3 33.2 -285.8 S°(J/mol∙K) 46.0 210.8 240.1 70.0

Correct AnswerverifiedShow Answer

Determine the equilibrium constant for the following reaction at 655 K. HCN(g) + 2 H2(g) → CH3NH2(g) ΔH° = -158 kJ;ΔS°= -219.9 J/K

Correct AnswerverifiedShow Answer

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Consider a reaction that is exothermic (...
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Spontaneity is a thermodynamic...
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Phosphorous and chlorine gases combine to produce phosphorous trichloride: P₂(g) + 3Cl₂(g) → 2PCl₃(g) ΔG° at 298 K for this reaction is -642.9 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P₂,1.6 atm Cl₂,and 0.65 atm PCl₃ is ________.

Correct Answer
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Correct Answer
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Correct Answer
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Estimate ΔG°_rxn for the following reaction at 775 K. 2 Hg(g) + O₂(g) → 2 HgO(s) ΔH° = -304.2 kJ;ΔS° = -414.2 J/K

Correct Answer
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Determine ΔG°_rxn using the following information. CaCO₃(s) → CaO(s) + CO₂(g) ΔH° = +179.2 kJ;ΔS° = +160.2 J/K

Correct Answer
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Determine the equilibrium constant for the following reaction at 549 K. CH₂O(g) + 2 H₂(g) → CH₄(g) + H₂O(g) ΔH° = -94.9 kJ;ΔS° = -224.2 J/K

Correct Answer
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The value of ΔG° at 100.0 °C for the formation of calcium chloride from its constituent elements: Ca(s) + Cl₂(g) → CaCl₂(s) Is ________ kJ/mol.At 25.0°C for this reaction,ΔH° is -795.8 kJ/mol,ΔG° is -748.1 kJ/mol,and ΔS° is -159.8 J/K.

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Calculate ΔS°_rxn for the following reaction.The S° for each species is shown below the reaction. P₄(g) + 10 Cl₂(g) → 4 PCl₅(g) S°(J/mol^∙K) 280.0 223.1 364.6

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Correct Answer
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An allotrope is an e...
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Use Hess's law to calculate ΔG°_rxn using the following information. NO(g) + O(g) → NO₂(g) ΔG°_rxn= ? 2 O₃(g) → 3 O₂(g) ΔG°_rxn= +489.6 kJ O₂(g) → 2 O(g) ΔG°_rxn= +463.4 kJ NO(g) + O₃(g) → NO₂(g) + O₂(g) ΔG°_rxn= -199.5 kJ

Correct Answer
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Correct Answer
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Use Hess's law to calculate ΔG°_rxn using the following information. CO(g) → C(s) + 1/2 O₂(g) ΔG°_rxn= ? CO₂(g) → C(s) + O₂(g) ΔG°_rxn= +394.4 kJ CO(g) + 1/2 O₂(g) → CO₂(g) ΔG°_rxn= -257.2 kJ

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Correct Answer
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Correct Answer
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Correct Answer
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Calculate the ΔG°_rxn using the following information. 2 HNO₃(aq) + NO(g) → 3 NO₂(g) + H₂O(l) ΔG°_rxn= ? ΔH°_f (kJ/mol) -207.0 91.3 33.2 -285.8 S°(J/mol^∙K) 46.0 210.8 240.1 70.0

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Determine the equilibrium constant for the following reaction at 655 K. HCN(g) + 2 H₂(g) → CH₃NH₂(g) ΔH° = -158 kJ;ΔS°= -219.9 J/K

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