Question 1

An exothermic reaction is a process that

Accepted Answer

A)  has a negative ΔHsys and a positive ΔSsurr. 
B)  has a negative ΔHsys and a negative ΔSsurr. 
C)  has a positive ΔHsys and a positive ΔSsurr. 
D)  has a positive ΔHsys and a negative ΔSsurr. 
A)  has a negative ΔHsys and a positive ΔSsurr. 
B)  has a negative ΔHsys and a negative ΔSsurr. 
C)  has a positive ΔHsys and a positive ΔSsurr. 
D)  has a positive ΔHsys and a negative ΔSsurr.

Question 2

________ is a thermodynamic function that increases with the number of energetically equivalent ways to arrange components of a system to achieve a particular state.

Accepted Answer

A)  Heat of fusion 
B)  Free energy 
C)  Entropy 
D)  Enthalpy 
E)  Molar nonequivalence 
A)  Heat of fusion 
B)  Free energy 
C)  Entropy 
D)  Enthalpy 
E)  Molar nonequivalence

Question 3

Define the third law of thermodynamics.

Accepted Answer

The entropy of a per

Question 4

Given the following equation, H2O(g)+ CO(g)→ H2(g)+ CO2(g)ΔG°rxn = -28.6 kJ
Calculate ΔG°rxn for the following reaction.
5 H2(g)+ 5 CO2(g)→ 5 H2O(g)+ 5 CO(g)

Accepted Answer

A)  -143.0 kJ 
B)  +143.0 kJ 
C)  -5.72 kJ 
D)  +5.72 kJ 
E)  -28.6 kJ 
A)  -143.0 kJ 
B)  +143.0 kJ 
C)  -5.72 kJ 
D)  +5.72 kJ 
E)  -28.6 kJ

Question 5

In the Haber process,ammonia is synthesized from nitrogen and hydrogen: N2(g)+ 3 H2(g)→ 2 NH3(g)
ΔG° at 298 K for this reaction is -33.3 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.9 atm N2,1.6 atm H2,and 0.65 atm NH3 is ________.

Accepted Answer

A)  -1.8 
B)  -3.86 × 103 
C)  -7.25 × 103 
D)  -104.5 
E)  -40.5 
A)  -1.8 
B)  -3.86 × 103 
C)  -7.25 × 103 
D)  -104.5 
E)  -40.5

Question 6

Above what temperature does the following reaction become nonspontaneous? FeO(s)+ CO(g)→ CO2(g)+ Fe(s)ΔH = -11.0 kJ; ΔS = -17.4 J/K

Accepted Answer

A)  632 K 
B)  298 K 
C)  191 K 
D)  This reaction is nonspontaneous at all temperatures. 
E)  This reaction is spontaneous at all temperatures. 
A)  632 K 
B)  298 K 
C)  191 K 
D)  This reaction is nonspontaneous at all temperatures. 
E)  This reaction is spontaneous at all temperatures.

Question 7

Identify the process which is exothermic and spontaneous.

Accepted Answer

A)  melting of ice at 25°C 
B)  melting of ice to water 
C)  dissolution of sodium chloride in water 
D)  All of them are exothermic and spontaneous. 
E)  None of them is exothermic and spontaneous. 
A)  melting of ice at 25°C 
B)  melting of ice to water 
C)  dissolution of sodium chloride in water 
D)  All of them are exothermic and spontaneous. 
E)  None of them is exothermic and spontaneous.

Question 8

Define the second law of thermodynamics.

Accepted Answer

For any spontaneous

Question 9

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

Accepted Answer

Consider a reaction that is exothermic (

Question 10

For a given reaction,ΔH = -19.9 kJ/mol and ΔS = -55.5 J/Kmol.The reaction will have ΔG = 0 at ________ K.Assume that ΔH and ΔS do not vary with temperature.

Accepted Answer

A)  359 
B)  2789 
C)  298 
D)  2.79 
E)  0.359 
A)  359 
B)  2789 
C)  298 
D)  2.79 
E)  0.359

Question 11

Given the following equation, C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g)ΔG°rxn = -2074 kJ
Calculate ΔG°rxn for the following reaction.
21 CO2(g)+ 28 H2O(g)→ 7 C3H8(g)+ 35 O2(g)

Accepted Answer

A)  -2074 kJ 
B)  +14518 kJ 
C)  -14518 kJ 
D)  +2074 kJ 
E)  -296 kJ 
A)  -2074 kJ 
B)  +14518 kJ 
C)  -14518 kJ 
D)  +2074 kJ 
E)  -296 kJ

Question 12

Which one of the following has the highest standard molar entropy,S°,at 45°C?

Accepted Answer

A)  I2(g) 
B)  H2(g) 
C)  Br2(l) 
D)  N2(g) 
E)  Cl2(g) 
A)  I2(g) 
B)  H2(g) 
C)  Br2(l) 
D)  N2(g) 
E)  Cl2(g)

Question 13

Identify the process that is spontaneous.

Accepted Answer

A)  rusting of iron 
B)  electrolysis 
C)  browning of bread 
D)  photosynthesis 
E)  frying an egg 
A)  rusting of iron 
B)  electrolysis 
C)  browning of bread 
D)  photosynthesis 
E)  frying an egg

Question 14

The ________ Law of Thermodynamics states the entropy of a perfect crystal at absolute zero is zero.

Accepted Answer

A)  Zero 
B)  First 
C)  Second 
D)  Third 
E)  Fourth 
A)  Zero 
B)  First 
C)  Second 
D)  Third 
E)  Fourth

Question 15

Determine the equilibrium constant for the following reaction at 298 K. SO3(g)+ H2O(g)→ H2SO4(l)ΔG° = -90.5 kJ

Accepted Answer

A)  1.37 × 10-16 
B)  4.78 × 1011 
C)  9.11 × 10-8 
D)  7.31 × 1015 
E)  0.964 
A)  1.37 × 10-16 
B)  4.78 × 1011 
C)  9.11 × 10-8 
D)  7.31 × 1015 
E)  0.964

Question 16

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

Accepted Answer

A)  -86.2 kJ 
B)  -91.5 kJ 
C)  +91.5 kJ 
D)  -89.6 kJ 
E)  +89.6 kJ 
A)  -86.2 kJ 
B)  -91.5 kJ 
C)  +91.5 kJ 
D)  -89.6 kJ 
E)  +89.6 kJ

Question 17

What is true if ln K is negative?

Accepted Answer

A)  ΔG°rxn is positive and the reaction is spontaneous in the forward direction. 
B)  ΔG°rxn is negative and the reaction is spontaneous in the forward direction. 
C)  ΔG°rxn is negative and the reaction is spontaneous in the reverse direction. 
D)  ΔG°rxn is positive and the reaction is spontaneous in the reverse direction. 
E)  ΔG°rxn is zero and the reaction is at equilibrium. 
A)  ΔG°rxn is positive and the reaction is spontaneous in the forward direction. 
B)  ΔG°rxn is negative and the reaction is spontaneous in the forward direction. 
C)  ΔG°rxn is negative and the reaction is spontaneous in the reverse direction. 
D)  ΔG°rxn is positive and the reaction is spontaneous in the reverse direction. 
E)  ΔG°rxn is zero and the reaction is at equilibrium.

Question 18

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 is true. 
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 is true.

Question 19

Consider the following reaction at constant P.Use the information here to determine the value of ΔSsurr at 355 K.Predict whether or not this reaction will be spontaneous at this temperature. 2 NO(g)+ O2(g)→ 2 NO2(g)ΔH = -114 kJ

Accepted Answer

A)  ΔSsurr = -114 kJ/K, reaction is spontaneous 
B)  ΔSsurr = +114 kJ/K, reaction is spontaneous 
C)  ΔSsurr = +321 J/K, reaction is spontaneous 
D)  ΔSsurr = -321 J/K, reaction is not spontaneous 
E)  ΔSsurr = +114 J/K, it is not possible to predict the spontaneity of this reaction without more information. 
A)  ΔSsurr = -114 kJ/K, reaction is spontaneous 
B)  ΔSsurr = +114 kJ/K, reaction is spontaneous 
C)  ΔSsurr = +321 J/K, reaction is spontaneous 
D)  ΔSsurr = -321 J/K, reaction is not spontaneous 
E)  ΔSsurr = +114 J/K, it is not possible to predict the spontaneity of this reaction without more information.

Question 20

Use Hess's law to calculate ΔG°rxn using the following information. ClO(g)+ O3(g)→ Cl(g)+ 2 O2(g)ΔG°rxn = ?
2 O3(g)→ 3 O2(g)ΔG°rxn = +489.6 kJ
Cl(g)+ O3(g)→ ClO(g)+ O2(g)ΔG°rxn = -34.5 kJ

Accepted Answer

A)  -472.4 kJ 
B)  +210.3 kJ 
C)  -524.1 kJ 
D)  -262.1 kJ 
E)  +524.1 kJ 
A)  -472.4 kJ 
B)  +210.3 kJ 
C)  -524.1 kJ 
D)  -262.1 kJ 
E)  +524.1 kJ

Exam 18: Free Energy and Thermodynamics

An exothermic reaction is a process that

________ is a thermodynamic function that increases with the number of energetically equivalent ways to arrange components of a system to achieve a particular state.

Define the third law of thermodynamics.

Given the following equation, H2O(g)+ CO(g)→ H2(g)+ CO2(g)ΔG°rxn = -28.6 kJ Calculate ΔG°rxn for the following reaction. 5 H2(g)+ 5 CO2(g)→ 5 H2O(g)+ 5 CO(g)

In the Haber process,ammonia is synthesized from nitrogen and hydrogen: N2(g)+ 3 H2(g)→ 2 NH3(g) ΔG° at 298 K for this reaction is -33.3 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.9 atm N2,1.6 atm H2,and 0.65 atm NH3 is ________.

Above what temperature does the following reaction become nonspontaneous? FeO(s)+ CO(g)→ CO2(g)+ Fe(s)ΔH = -11.0 kJ; ΔS = -17.4 J/K

Identify the process which is exothermic and spontaneous.

Define the second law of thermodynamics.

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

For a given reaction,ΔH = -19.9 kJ/mol and ΔS = -55.5 J/Kmol.The reaction will have ΔG = 0 at ________ K.Assume that ΔH and ΔS do not vary with temperature.

Given the following equation, C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g)ΔG°rxn = -2074 kJ Calculate ΔG°rxn for the following reaction. 21 CO2(g)+ 28 H2O(g)→ 7 C3H8(g)+ 35 O2(g)

Which one of the following has the highest standard molar entropy,S°,at 45°C?

Identify the process that is spontaneous.

The ________ Law of Thermodynamics states the entropy of a perfect crystal at absolute zero is zero.

Determine the equilibrium constant for the following reaction at 298 K. SO3(g)+ H2O(g)→ H2SO4(l)ΔG° = -90.5 kJ

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

What is true if ln K is negative?

Which of the following statements is TRUE?

Consider the following reaction at constant P.Use the information here to determine the value of ΔSsurr at 355 K.Predict whether or not this reaction will be spontaneous at this temperature. 2 NO(g)+ O2(g)→ 2 NO2(g)ΔH = -114 kJ

Use Hess's law to calculate ΔG°rxn using the following information. ClO(g)+ O3(g)→ Cl(g)+ 2 O2(g)ΔG°rxn = ? 2 O3(g)→ 3 O2(g)ΔG°rxn = +489.6 kJ Cl(g)+ O3(g)→ ClO(g)+ O2(g)ΔG°rxn = -34.5 kJ

Matter, measurement, and Problem Solving

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Given the following equation, H₂O(g)+ CO(g)→ H₂(g)+ CO₂(g)ΔG°_rxn = -28.6 kJ Calculate ΔG°_rxn for the following reaction. 5 H₂(g)+ 5 CO₂(g)→ 5 H₂O(g)+ 5 CO(g)

In the Haber process,ammonia is synthesized from nitrogen and hydrogen: N₂(g)+ 3 H₂(g)→ 2 NH₃(g) ΔG° at 298 K for this reaction is -33.3 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.9 atm N₂,1.6 atm H₂,and 0.65 atm NH₃ is ________.

Above what temperature does the following reaction become nonspontaneous? FeO(s)+ CO(g)→ CO₂(g)+ Fe(s)ΔH = -11.0 kJ; ΔS = -17.4 J/K

Given the following equation, C₃H₈(g)+ 5 O₂(g)→ 3 CO₂(g)+ 4 H₂O(g)ΔG°_rxn = -2074 kJ Calculate ΔG°_rxn for the following reaction. 21 CO₂(g)+ 28 H₂O(g)→ 7 C₃H₈(g)+ 35 O₂(g)

Determine the equilibrium constant for the following reaction at 298 K. SO₃(g)+ H₂O(g)→ H₂SO₄(l)ΔG° = -90.5 kJ

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

Consider the following reaction at constant P.Use the information here to determine the value of ΔS_surrat 355 K.Predict whether or not this reaction will be spontaneous at this temperature. 2 NO(g)+ O₂(g)→ 2 NO₂(g)ΔH = -114 kJ

Use Hess's law to calculate ΔG°_rxn using the following information. ClO(g)+ O₃(g)→ Cl(g)+ 2 O₂(g)ΔG°_rxn= ? 2 O₃(g)→ 3 O₂(g)ΔG°_rxn= +489.6 kJ Cl(g)+ O₃(g)→ ClO(g)+ O₂(g)ΔG°_rxn= -34.5 kJ