Question 1

Consider the reaction:
 
What is ΔrG° for this reaction in kJ at 500 K?

Accepted Answer

A) 93 kJ 
B) 151 kJ 
C) 365 kJ 
D) -1.00 × 105 kJ 
E) 441 kJ 
A) 93 kJ 
B) 151 kJ 
C) 365 kJ 
D) -1.00 × 105 kJ 
E) 441 kJ

Question 2

A microstate is a specific microscopic configuration describing how particles
of a system are distributed among the available energy levels.

Accepted Answer

A) True 
 B)False

Question 3

Consider the following reaction:
 
What is Keq for this reaction at 25 °C?

Accepted Answer

A) e324  
B) e-324  
C) e162  
D) e-162  
E) 1.38 
A) e324  
B) e-324  
C) e162  
D) e-162  
E) 1.38

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 L 
A) 17 °C and 15 L 
B) 127 °C and 15 L 
C) 17 °C and 25 L 
D) 127 °C and 25 L

Question 5

Entropy changes depend on the quantities of substances involved.

Accepted Answer

A) True 
 B)False

Question 6

For the reaction

What is DrSo?

Accepted Answer

A) -88.5 J/mol ∙ K 
B) -176.7 J/mol ∙ K 
C) 219 J/mol ∙ K 
D) 176.7 J/mol ∙ K 
E) -219.1 J/mol ∙ K 
A) -88.5 J/mol ∙ K 
B) -176.7 J/mol ∙ K 
C) 219 J/mol ∙ K 
D) 176.7 J/mol ∙ K 
E) -219.1 J/mol ∙ K

Question 7

For the reaction N2O3(g)→ NO(g)+ NO2(g)ΔrG° = -4.78 kJ/mol.Calculate Keq at 25 °C.

Accepted Answer

A) 1.023 
B) 1.002 
C) 1.005 
D) 0.9484 
E) 0.9981 
A) 1.023 
B) 1.002 
C) 1.005 
D) 0.9484 
E) 0.9981

Question 8

Indicate the statement(s)which is (are)true for the process:
Al+3(aq)+ 3 OH-(aq)→ Al(OH)3(s)
If it occurs in a closed container.
I.ΔS increases because the final molecule is more complicated.
II.Entropy decreases because the product is in the solid phase.
III.The two ions achieve a high degree of order as they crystalize,therefore ΔS is positive.
IV.Entropy of the system is unchanged because the system is sealed and at a constant temperature.

Accepted Answer

A) I and II 
B) I and III 
C) II only 
D) I,II,IV 
E) I and IV 
A) I and II 
B) I and III 
C) II only 
D) I,II,IV 
E) I and IV

Question 9

Consider the following reaction:
 
What is ΔrS° in J/mol K?

Accepted Answer

A) 127.6 J/mol K 
B) -127.6 J/mol K 
C) 3.0 J/mol K 
D) -258.2 J/mol K 
E) -3.0 J/mol K 
A) 127.6 J/mol K 
B) -127.6 J/mol K 
C) 3.0 J/mol K 
D) -258.2 J/mol K 
E) -3.0 J/mol K

Question 10

A non spontaneous reaction can be made to occur by coupling it with a spontaneous reaction to form an overall spontaneous reaction.

Accepted Answer

A) True 
 B)False

Question 11

Consider the reaction:
H2X(g)→ HX(g)+ X(g)
ΔrH° = 18.4 kJ/mol ΔrS°= 23.1 J/mol K
What is Keq for this reaction at 525 K?

Accepted Answer

A) 0.387  
B) 0.993 
C) 0.238 
D) 4.23 
E) 1.01 
A) 0.387  
B) 0.993 
C) 0.238 
D) 4.23 
E) 1.01

Question 12

For the reaction PCl5(g)→ PCl3(g)+ Cl2(g)at 298 K,Keq = 1.87 × 10-7,ΔrS° = 181.92 J/mol K,what is Keq at 200 K if ΔrH° = 92.6 kJ/mol?

Accepted Answer

A) 2.08 × 10-15  
B) 16.8 
C) 1.87 × 10-7  
D) 5.35 × 106  
E) 5.95 × 10-2  
A) 2.08 × 10-15  
B) 16.8 
C) 1.87 × 10-7  
D) 5.35 × 106  
E) 5.95 × 10-2

Question 13

If ΔG is positive for a certain reaction,then:

Accepted Answer

A) the reaction is spontaneous 
B) the reverse of the reaction is spontaneous 
C) the system is in equilibrium 
D) one would need to know the Kelvin temperature to determine spontaneity 
E) there would be no reaction possible for a negative value 
A) the reaction is spontaneous 
B) the reverse of the reaction is spontaneous 
C) the system is in equilibrium 
D) one would need to know the Kelvin temperature to determine spontaneity 
E) there would be no reaction possible for a negative value

Question 14

For CdO(s)+ SO3(g)→ CdSO4(s),ΔrH° = -279.4 kJ/mol,and ΔrS° = -118.4 J/mol K.What is ΔrG° in kJ/mol at 127 K?

Accepted Answer

A) -256 kJ/mol 
B) -303 kJ/mol 
C) -264 kJ/mol 
D) -355 kJ/mol 
E) -460 kJ/mol 
A) -256 kJ/mol 
B) -303 kJ/mol 
C) -264 kJ/mol 
D) -355 kJ/mol 
E) -460 kJ/mol

Question 15

What is ΔrG° at 25 °C?
CaCO3(s)→ CaO(s)+ CO2(g)ΔrH° = 177.8 kJ ΔrS° = 160.7 J/K

Accepted Answer

A) 1779 kJ 
B) 173.8 kJ 
C) 225.7 kJ 
D) 181.8 kJ 
E) 129.9 kJ 
A) 1779 kJ 
B) 173.8 kJ 
C) 225.7 kJ 
D) 181.8 kJ 
E) 129.9 kJ

Question 16

For Cl2O(g)+ 3/2 O2(g)→ 2 ClO2 △rH° = 126 kJ/mol,and ΔrS° = -74.9 J/(mol K)at 377 °C.What is Keq?

Accepted Answer

A) 0.97 
B) 6.12 × 10-7  
C) 4.27 × 10-22  
D) 9.17 × 10-15  
E) 1.07 × 1014  
A) 0.97 
B) 6.12 × 10-7  
C) 4.27 × 10-22  
D) 9.17 × 10-15  
E) 1.07 × 1014

Question 17

Choose the INCORRECT statement.

Accepted Answer

A) One form of the second law of thermodynamics is all spontaneous processes produce an increase in the entropy of the universe. 
B) Gibbs energy is defined by: G = H - TS. 
C) If ΔG  0,the process is nonspontaneous. 
E) If ΔG = 0,the process is spontaneous. 
A) One form of the second law of thermodynamics is all spontaneous processes produce an increase in the entropy of the universe. 
B) Gibbs energy is defined by: G = H - TS. 
C) If ΔG  0,the process is nonspontaneous. 
E) If ΔG = 0,the process is spontaneous.

Question 18

The change in Gibbs energy of a reaction:

Accepted Answer

A) = work 
B) predicts speed 
C) = ΔH + TΔS 
D) depends on the standard state chosen 
E) tells us if the reaction is spontaneous or not 
A) = work 
B) predicts speed 
C) = ΔH + TΔS 
D) depends on the standard state chosen 
E) tells us if the reaction is spontaneous or not

Question 19

Predict whether ΔS is positive or negative for the following process:
2 Cl2O7(g)→ 2 Cl2(g)+ 7 O2(g)

Accepted Answer

A) negative 
B) positive 
C) ΔS doesn't change. 
D) There is not enough information to determine. 
A) negative 
B) positive 
C) ΔS doesn't change. 
D) There is not enough information to determine.

Question 20

Non spontaneous reactions and spontaneous reactions cannot be coupled.

Accepted Answer

A) True 
 B)False

Exam 13: Spontaneous Change: Entropy and Gibbs Energy

Consider the reaction: What is ΔrG° for this reaction in kJ at 500 K?

A microstate is a specific microscopic configuration describing how particles of a system are distributed among the available energy levels.

Consider the following reaction: What is Keq for this reaction at 25 °C?

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

Entropy changes depend on the quantities of substances involved.

For the reaction What is DrSo?

For the reaction N2O3(g)→ NO(g)+ NO2(g)ΔrG° = -4.78 kJ/mol.Calculate Keq at 25 °C.

Consider the following reaction: What is ΔrS° in J/mol K?

A non spontaneous reaction can be made to occur by coupling it with a spontaneous reaction to form an overall spontaneous reaction.

Consider the reaction: H2X(g)→ HX(g)+ X(g) ΔrH° = 18.4 kJ/mol ΔrS°= 23.1 J/mol K What is Keq for this reaction at 525 K?

For the reaction PCl5(g)→ PCl3(g)+ Cl2(g)at 298 K,Keq = 1.87 × 10-7,ΔrS° = 181.92 J/mol K,what is Keq at 200 K if ΔrH° = 92.6 kJ/mol?

If ΔG is positive for a certain reaction,then:

For CdO(s)+ SO3(g)→ CdSO4(s),ΔrH° = -279.4 kJ/mol,and ΔrS° = -118.4 J/mol K.What is ΔrG° in kJ/mol at 127 K?

What is ΔrG° at 25 °C? CaCO3(s)→ CaO(s)+ CO2(g)ΔrH° = 177.8 kJ ΔrS° = 160.7 J/K

For Cl2O(g)+ 3/2 O2(g)→ 2 ClO2 △rH° = 126 kJ/mol,and ΔrS° = -74.9 J/(mol K)at 377 °C.What is Keq?

Choose the INCORRECT statement.

The change in Gibbs energy of a reaction:

Predict whether ΔS is positive or negative for the following process: 2 Cl2O7(g)→ 2 Cl2(g)+ 7 O2(g)

Non spontaneous reactions and spontaneous reactions cannot be coupled.

Matter: Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Valence Bond and Molecular Orbital Theories

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acidbase Equilibria

Solubility and Complex-Ion Equilibria

Electrochemistry

Chemical Kinetics

Chemistry of the Main-Group Elements I: Groups 1,2,13,and 14

Chemistry of the Main-Group Elements Ii: Groups 18,17,16,15,and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

Consider the reaction: What is Δ_rG° for this reaction in kJ at 500 K?

Consider the following reaction: What is K_eq for this reaction at 25 °C?

For the reaction What is D_rS^o?

For the reaction N₂O₃(g)→ NO(g)+ NO₂(g)Δ_rG° = -4.78 kJ/mol.Calculate K_eq at 25 °C.

Consider the following reaction: What is Δ_rS° in J/mol K?

Consider the reaction: H₂X(g)→ HX(g)+ X(g) Δ_rH° = 18.4 kJ/mol Δ_rS°= 23.1 J/mol K What is K_eq for this reaction at 525 K?

For the reaction PCl₅(g)→ PCl₃(g)+ Cl₂(g)at 298 K,K_eq = 1.87 × 10^-7,Δ_rS° = 181.92 J/mol K,what is K_eq at 200 K if Δ_rH° = 92.6 kJ/mol?

For CdO(s)+ SO₃(g)→ CdSO₄(s),Δ_rH° = -279.4 kJ/mol,and Δ_rS° = -118.4 J/mol K.What is Δ_rG° in kJ/mol at 127 K?

What is Δ_rG° at 25 °C? CaCO₃(s)→ CaO(s)+ CO₂(g)Δ_rH° = 177.8 kJ Δ_rS° = 160.7 J/K

For Cl₂O(g)+ 3/2 O₂(g)→ 2 ClO₂ △_rH° = 126 kJ/mol,and Δ_rS° = -74.9 J/(mol K)at 377 °C.What is K_eq?

Predict whether ΔS is positive or negative for the following process: 2 Cl₂O₇(g)→ 2 Cl₂(g)+ 7 O₂(g)