Question 1

If a reaction has a value of˙-16.5 kJ/mol for ˙∆H° and a value of -150 J/mol K for ∆S°,what is the value of the equilibrium constant at 25°C?

Accepted Answer

A)  9.42 × 103 
B)  1.14 x10-5 
C)  6.52 × 10-2 
D)  8.27 
A)  9.42 × 103 
B)  1.14 x10-5 
C)  6.52 × 10-2 
D)  8.27

Question 2

Which of the following statements is TRUE?

Accepted Answer

A)  Entropy is not a state function. 
B)  Endothermic processes decrease the entropy of the surroundings, at constant T and P. 
C)  Endothermic processes are never spontaneous. 
D)  Exothermic processes are always spontaneous. 
E)  None of the above are true. 
A)  Entropy is not a state function. 
B)  Endothermic processes decrease the entropy of the surroundings, at constant T and P. 
C)  Endothermic processes are never spontaneous. 
D)  Exothermic processes are always spontaneous. 
E)  None of the above are true.

Question 3

In the Haber process,ammonia is synthesized from nitrogen and hydrogen: N2(g)+ 3H2(g)→ 2NH3(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 1.5 atm N2,1.6 atm H2,and 0.65 atm NH3 is

Accepted Answer

A)  -2.3 
B)  -3.27 × 103 
C)  -6.67 × 103 
D)  -98.8 
E)  -39.9 
A)  -2.3 
B)  -3.27 × 103 
C)  -6.67 × 103 
D)  -98.8 
E)  -39.9

Question 4

Calculate ΔS°rxn for the following reaction.The S° for each species is shown below the reaction. C2H2(g)+ H2(g)→ C2H4(g)
S°(J/mol∙K)200.9 130.7 219.3

Accepted Answer

A)  +112.3 J/K 
B)  +550.9 J/K 
C)  -112.3 J/K 
D)  +337.1 J/K 
E)  -550.9 J/K 
A)  +112.3 J/K 
B)  +550.9 J/K 
C)  -112.3 J/K 
D)  +337.1 J/K 
E)  -550.9 J/K

Question 5

Consider a reaction that has a positive ΔH and a positive ΔS.Which of the following statements is TRUE?

Accepted Answer

A)  This reaction will be spontaneous only at high temperatures. 
B)  This reaction will be spontaneous at all temperatures. 
C)  This reaction will be nonspontaneous at all temperatures. 
D)  This reaction will be nonspontaneous only at high temperatures. 
E)  It is not possible to determine without more information. 
A)  This reaction will be spontaneous only at high temperatures. 
B)  This reaction will be spontaneous at all temperatures. 
C)  This reaction will be nonspontaneous at all temperatures. 
D)  This reaction will be nonspontaneous only at high temperatures. 
E)  It is not possible to determine without more information.

Question 6

At what temperature does a perfect crystalline solid have S=0?

Accepted Answer

A)  0 K 
B)  0°C 
C)  100 °C 
D)  273 K 
E)  It is not possible for a substance to have S=0. 
A)  0 K 
B)  0°C 
C)  100 °C 
D)  273 K 
E)  It is not possible for a substance to have S=0.

Question 7

Define entropy.

Accepted Answer

Entropy is a thermodynamic fun

Question 8

Give the standard states for a gas,liquid,solid,and solution.

Accepted Answer

For a gas - 1 atm; for a liqui

Question 9

Define the second law of thermodynamics.

Accepted Answer

For any spontaneous

Question 10

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ?
ΔG°f (kJ/mol)-73.5 149.3 -237.1

Accepted Answer

A)  -3.298 × 103 kJ 
B)  -312.9 kJ 
C)  +2.845 × 103 kJ 
D)  +110.7 kJ 
E)  -954.7 kJ 
A)  -3.298 × 103 kJ 
B)  -312.9 kJ 
C)  +2.845 × 103 kJ 
D)  +110.7 kJ 
E)  -954.7 kJ

Question 11

Which of the following processes have a ΔS < 0?

Accepted Answer

A)  water freezes 
B)  isopropyl alcohol condenses 
C)  ethanol (g, at 555 K) → ethanol (g, at 400 K) 
D)  carbon dioxide(g) → carbon dioxide(s) 
E)  All of the above processes have a ΔS < 0. 
A)  water freezes 
B)  isopropyl alcohol condenses 
C)  ethanol (g, at 555 K) → ethanol (g, at 400 K) 
D)  carbon dioxide(g) → carbon dioxide(s) 
E)  All of the above processes have a ΔS < 0.

Question 12

According to the Second Law of Thermodynamics,in order for a reaction to be spontaneous which value must increase?

Accepted Answer

A)  ∆Ssurr 
B)  ∆Ssys 
C)  ∆Suniverse 
D)  ∆Hrxn 
E)  ∆T 
A)  ∆Ssurr 
B)  ∆Ssys 
C)  ∆Suniverse 
D)  ∆Hrxn 
E)  ∆T

Question 13

Why can endothermic reactions be spontaneous?

Accepted Answer

Even though an endothermic process requi

Question 14

Calculate the ΔG°rxn using the following information. 2 HNO3(aq)+ NO(g)→ 3 NO2(g)+ H2O(l)ΔG°rxn = ?
ΔG°f (kJ/mol)-110.9 87.6 51.3 -237.1

Accepted Answer

A)  -162.5 kJ 
B)  +51.0 kJ 
C)  -54.5 kJ 
D)  +171.1 kJ 
E)  -87.6 kJ 
A)  -162.5 kJ 
B)  +51.0 kJ 
C)  -54.5 kJ 
D)  +171.1 kJ 
E)  -87.6 kJ

Question 15

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ?
ΔH°f (kJ/mol)-133.9 50.6 -285.8
S°(J/mol∙K)266.9 121.2 191.6 70.0

Accepted Answer

A)  +4.90 × 103 kJ 
B)  +3.90 × 103 kJ 
C)  -2.04 × 103 kJ 
D)  -3.15 × 103 kJ 
E)  -3.30 × 103 kJ 
A)  +4.90 × 103 kJ 
B)  +3.90 × 103 kJ 
C)  -2.04 × 103 kJ 
D)  -3.15 × 103 kJ 
E)  -3.30 × 103 kJ

Question 16

The value of ΔG° at 141.0°C for the formation of phosphorous trichloride from its constituent elements, P2(g)+ 3Cl2(g)→ 2PCl3(g)
Is ________ kJ/mol.At 25.0°C for this reaction,ΔH° is -720.5 kJ/mol,ΔG° is -642.9 kJ/mol,and ΔS° is -263.7 J/K.

Accepted Answer

A)  -612.3 
B)  3.65 × 104 
C)  1.08 × 105 
D)  -683.3 
E)  -829.7 
A)  -612.3 
B)  3.65 × 104 
C)  1.08 × 105 
D)  -683.3 
E)  -829.7

Question 17

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

Question 18

Identify the statement that is FALSE.

Accepted Answer

A)  The entropy of a gas is greater than the entropy of a liquid. 
B)  Entropy generally increases with increasing molecular complexity. 
C)  Free atoms have greater entropy than molecules. 
D)  Entropy increases with dissolution. 
E)  For noble gasses, entropy increases with size. 
A)  The entropy of a gas is greater than the entropy of a liquid. 
B)  Entropy generally increases with increasing molecular complexity. 
C)  Free atoms have greater entropy than molecules. 
D)  Entropy increases with dissolution. 
E)  For noble gasses, entropy increases with size.

Question 19

Calculate ∆S°rxn for the following reaction.The S° for each species is shown below the reaction. 2NO(g)+ 2 H2(g)→ N2(g)+ 2 H2O(l)
S°(J/mol∙K)210.8 130.7 191.6 69.9

Accepted Answer

A)  +1183.8 J/K 
B)  -351.6 J/K 
C)  -469.3 J/K 
D)  +503.9 J/K 
E)  +111.4 J/K 
A)  +1183.8 J/K 
B)  -351.6 J/K 
C)  -469.3 J/K 
D)  +503.9 J/K 
E)  +111.4 J/K

Question 20

Which of the following processes have a ΔS < 0?

Accepted Answer

A)  The melting of a cube of ice 
B)  Dissolving of salt into water 
C)  Water boiling on the stovetop 
D)  Dry ice sublimating into carbon dioxide gas 
E)  Condensation of water vapor into rain drops 
A)  The melting of a cube of ice 
B)  Dissolving of salt into water 
C)  Water boiling on the stovetop 
D)  Dry ice sublimating into carbon dioxide gas 
E)  Condensation of water vapor into rain drops

Exam 19: Free Energy and Thermodynamics

If a reaction has a value of˙-16.5 kJ/mol for ˙∆H° and a value of -150 J/mol K for ∆S°,what is the value of the equilibrium constant at 25°C?

Which of the following statements is TRUE?

In the Haber process,ammonia is synthesized from nitrogen and hydrogen: N2(g)+ 3H2(g)→ 2NH3(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 1.5 atm N2,1.6 atm H2,and 0.65 atm NH3 is

Calculate ΔS°rxn for the following reaction.The S° for each species is shown below the reaction. C2H2(g)+ H2(g)→ C2H4(g) S°(J/mol∙K)200.9 130.7 219.3

Consider a reaction that has a positive ΔH and a positive ΔS.Which of the following statements is TRUE?

At what temperature does a perfect crystalline solid have S=0?

Define entropy.

Give the standard states for a gas,liquid,solid,and solution.

Define the second law of thermodynamics.

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ? ΔG°f (kJ/mol)-73.5 149.3 -237.1

Which of the following processes have a ΔS < 0?

According to the Second Law of Thermodynamics,in order for a reaction to be spontaneous which value must increase?

Why can endothermic reactions be spontaneous?

Calculate the ΔG°rxn using the following information. 2 HNO3(aq)+ NO(g)→ 3 NO2(g)+ H2O(l)ΔG°rxn = ? ΔG°f (kJ/mol)-110.9 87.6 51.3 -237.1

Calculate the ΔG°rxn using the following information. 4 HNO3(g)+ 5 N2H4(l)→ 7 N2(g)+ 12 H2O(l)ΔG°rxn = ? ΔH°f (kJ/mol)-133.9 50.6 -285.8 S°(J/mol∙K)266.9 121.2 191.6 70.0

The value of ΔG° at 141.0°C for the formation of phosphorous trichloride from its constituent elements, P2(g)+ 3Cl2(g)→ 2PCl3(g) Is ________ kJ/mol.At 25.0°C for this reaction,ΔH° is -720.5 kJ/mol,ΔG° is -642.9 kJ/mol,and ΔS° is -263.7 J/K.

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

Identify the statement that is FALSE.

Calculate ∆S°rxn for the following reaction.The S° for each species is shown below the reaction. 2NO(g)+ 2 H2(g)→ N2(g)+ 2 H2O(l) S°(J/mol∙K)210.8 130.7 191.6 69.9

Which of the following processes have a ΔS < 0?

Essentials: Units, Measurements, and Problem Solving

Atoms

The Quantum Mechanical Model of the Atom

Periodic Properties of the Elements

Molecules and Compounds

Chemical Bonding I

Chemical Bonding Ii

Chemical Reactions and Chemical Quantities

Introduction to Solutions and Aqueous Reactions

Thermochemistry

Gases

Liquids, Solids, and Intermolecular Forces

Crystalline Solids and Modern Materials

Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Aqueous Ionic Equilibrium

Electrochemistry

Radioactivity and Nuclear Chemistry

Organic Chemistry

Transition Metals and Coordination Compounds

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In the Haber process,ammonia is synthesized from nitrogen and hydrogen: N₂(g)+ 3H₂(g)→ 2NH₃(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 1.5 atm N₂,1.6 atm H₂,and 0.65 atm NH₃ is

Calculate ΔS°_rxn for the following reaction.The S° for each species is shown below the reaction. C₂H₂(g)+ H₂(g)→ C₂H₄(g) S°(J/mol^∙K)200.9 130.7 219.3

Calculate the ΔG°_rxn using the following information. 4 HNO₃(g)+ 5 N₂H₄(l)→ 7 N₂(g)+ 12 H₂O(l)ΔG°_rxn= ? ΔG°_f (kJ/mol)-73.5 149.3 -237.1

Calculate the ΔG°_rxn using the following information. 2 HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)ΔG°_rxn= ? ΔG°_f (kJ/mol)-110.9 87.6 51.3 -237.1

Calculate the ΔG°_rxn using the following information. 4 HNO₃(g)+ 5 N₂H₄(l)→ 7 N₂(g)+ 12 H₂O(l)ΔG°_rxn= ? ΔH°_f (kJ/mol)-133.9 50.6 -285.8 S°(J/mol^∙K)266.9 121.2 191.6 70.0

The value of ΔG° at 141.0°C for the formation of phosphorous trichloride from its constituent elements, P₂(g)+ 3Cl₂(g)→ 2PCl₃(g) Is ________ kJ/mol.At 25.0°C for this reaction,ΔH° is -720.5 kJ/mol,ΔG° is -642.9 kJ/mol,and ΔS° is -263.7 J/K.

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

Calculate ∆S°_rxn for the following reaction.The S° for each species is shown below the reaction. 2NO(g)+ 2 H₂(g)→ N₂(g)+ 2 H₂O(l) S°(J/mol^∙K)210.8 130.7 191.6 69.9