Question 1

For the reaction PCl5(g)→ PCl3(g)+ Cl2(g)at 298 K,Keq = 1.87 × 10-7,what is ΔrG ° and is the reaction spontaneous?

Accepted Answer

A) 3.84 × 104 kJ/mol,no 
B) 7.68 kJ/mol,no 
C) -7.68 kJ/mol,yes 
D) 38.4 kJ/mol,no 
E) -38.4 kJ/mol,yes 
A) 3.84 × 104 kJ/mol,no 
B) 7.68 kJ/mol,no 
C) -7.68 kJ/mol,yes 
D) 38.4 kJ/mol,no 
E) -38.4 kJ/mol,yes

Question 2

The maximum quantity of energy available for useful work is:

Accepted Answer

A) constant 
B) Gibbs energy change 
C) the entropy change 
D) the internal energy change 
E) the enthalpy change 
A) constant 
B) Gibbs energy change 
C) the entropy change 
D) the internal energy change 
E) the enthalpy change

Question 3

Find correct statements.
I.A spontaneous process is a process that occurs in a system left to itself.
II.A non spontaneous process will not occur unless some external force is applied.
III.If a reaction is spontaneous,the reverse is also spontaneous.
IV.Only spontaneous processes occur naturally.
V.Entropy is inversely proportional to the degree of randomness.

Accepted Answer

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

Question 4

The following reaction is exothermic.
2 N2O(g)→ 2 N2(g)+ O2(g)
This means the reaction:

Accepted Answer

A) will be spontaneous at all temperatures 
B) will be spontaneous only at high temperature 
C) will be spontaneous only at low temperatures 
D) is not spontaneous at any temperature 
E) cannot determine without temperature 
A) will be spontaneous at all temperatures 
B) will be spontaneous only at high temperature 
C) will be spontaneous only at low temperatures 
D) is not spontaneous at any temperature 
E) cannot determine without temperature

Question 5

A reaction is spontaneous if:
I.ΔG is a negative value
II.both enthalpy and entropy increase
III.ΔH is negative and ΔS is positive
IV.both enthalpy and entropy decrease
V.ΔH is positive and ΔS is negative

Accepted Answer

A) I and III 
B) I and II 
C) II and V 
D) III and IV 
E) II and IV 
A) I and III 
B) I and II 
C) II and V 
D) III and IV 
E) II and IV

Question 6

What is ΔrG°?

Accepted Answer

A) 326.2 kJ 
B) -326.4 kJ 
C) -163.2 kJ 
D) 163.2 kJ 
E) 54.4 kJ 
A) 326.2 kJ 
B) -326.4 kJ 
C) -163.2 kJ 
D) 163.2 kJ 
E) 54.4 kJ

Question 7

Which of the following has the highest entropy?

Accepted Answer

A) 1 mole of liquid water at 30 °C 
B) 1 mole of water vapor at 30 °C 
C) 1 mole of regular ice at -10 °C 
D) 1 mole of "dry ice" at -10 °C 
E) 1 mole of water under 10 atm of pressure at -10 °C 
A) 1 mole of liquid water at 30 °C 
B) 1 mole of water vapor at 30 °C 
C) 1 mole of regular ice at -10 °C 
D) 1 mole of "dry ice" at -10 °C 
E) 1 mole of water under 10 atm of pressure at -10 °C

Question 8

For the reaction
 
What is DrSo?

Accepted Answer

A) 262.5 J/mol ∙ K 
B) -85.1 J/mol ∙ K 
C) -164.7 J/mol ∙ K 
D) 164.7 J/mol ∙ K 
E) 85.1 J/mol ∙ K 
A) 262.5 J/mol ∙ K 
B) -85.1 J/mol ∙ K 
C) -164.7 J/mol ∙ K 
D) 164.7 J/mol ∙ K 
E) 85.1 J/mol ∙ K

Question 9

What is ΔrG° at 25 °C?
CO(g)+ 2 H2(g)→ CH3OH(g)ΔrH° = -90.7 kJ ΔrS° = -221 J/K

Accepted Answer

A) -90.9 kJ 
B) -24.8 kJ 
C) -156.6 kJ 
D) -96.2 kJ 
E) -85.2 kJ 
A) -90.9 kJ 
B) -24.8 kJ 
C) -156.6 kJ 
D) -96.2 kJ 
E) -85.2 kJ

Question 10

What is ΔrG°?

Accepted Answer

A) 149.1 kJ 
B) -4.8 kJ 
C) -46.5 kJ 
D) 4.8 kJ 
E) 46.5 kJ 
A) 149.1 kJ 
B) -4.8 kJ 
C) -46.5 kJ 
D) 4.8 kJ 
E) 46.5 kJ

Question 11

?rG ?  is independent of temperature.

Accepted Answer

A) True 
 B)False

Question 12

Calculate ΔrG° for the reaction Cu(s)+ H2O(g)→ CuO(s)+ H2(g)at 500 K.

Accepted Answer

A) 231.8 kJ 
B) -135.4 kJ 
C) -58.6 kJ 
D) 110.6 kJ 
E) 86.74 kJ 
A) 231.8 kJ 
B) -135.4 kJ 
C) -58.6 kJ 
D) 110.6 kJ 
E) 86.74 kJ

Question 13

What is ΔrG° at 25 °C?
2O3(g)→ 3 O2(g)ΔrH° = -284 kJ ΔrS° = 139 J/K

Accepted Answer

A) -145 kJ 
B) -243 kJ 
C) -325 kJ 
D) -281 kJ 
E) -287 kJ 
A) -145 kJ 
B) -243 kJ 
C) -325 kJ 
D) -281 kJ 
E) -287 kJ

Question 14

The enthalpy change for converting 1.00 mol of ice at -50.0 °C to water at 70.0 °C is   The specific heats of ice,water,and steam are     And   Respectively.For   O,   = 6.01 kJ mol-1,and  .

Accepted Answer

A) 12.28 
B) 6.41 
C) 13.16 
D) 7154 
E) 9.40 
A) 12.28 
B) 6.41 
C) 13.16 
D) 7154 
E) 9.40

Question 15

For the reaction I2(s)+ Cl2(g)→ 2 ICl(g),ΔrH = 36 kJ/mol,and ΔrS = 158.8 J/mol K at 25 °C.Calculate the temperature at which Keq is 4.0 × 103.

Accepted Answer

A) 128 °C 
B) -115 °C 
C) 83 °C 
D) 25 °C 
E) -175 °C 
A) 128 °C 
B) -115 °C 
C) 83 °C 
D) 25 °C 
E) -175 °C

Question 16

Predict whether ΔS is positive or negative for the following process:
H2(g)+ 1/2 O2(g)→ H2O(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 17

Which of the following best expresses the increase in entropy associated with melting and sublimation,respectively?

Accepted Answer

A) ΔfusS - ΔsubS = 0 
B) ΔfusS = 144.3 J/mol-K,ΔsubS = 9.0 J/mol-K 
C) ΔfusS = 9.0 J/mol-K,ΔsubS = -144.3 J/mol-K 
D) ΔH for both processes is zero 
E) ΔfusS = 9.0 J/mol-K,ΔsubS= 144.3 J/mol-K 
A) ΔfusS - ΔsubS = 0 
B) ΔfusS = 144.3 J/mol-K,ΔsubS = 9.0 J/mol-K 
C) ΔfusS = 9.0 J/mol-K,ΔsubS = -144.3 J/mol-K 
D) ΔH for both processes is zero 
E) ΔfusS = 9.0 J/mol-K,ΔsubS= 144.3 J/mol-K

Question 18

The entropy of a system always increases for a spontaneous process.

Accepted Answer

A) True 
 B)False

Question 19

A spontaneous process will occur only if an external action is continually applied.

Accepted Answer

A) True 
 B)False

Question 20

The entropy of a pure perfect crystal at 25 K is zero.

Accepted Answer

A) True 
 B)False

Exam 13: Spontaneous Change: Entropy and Gibbs Energy

For the reaction PCl5(g)→ PCl3(g)+ Cl2(g)at 298 K,Keq = 1.87 × 10-7,what is ΔrG ° and is the reaction spontaneous?

The maximum quantity of energy available for useful work is:

The following reaction is exothermic. 2 N2O(g)→ 2 N2(g)+ O2(g) This means the reaction:

A reaction is spontaneous if: I.ΔG is a negative value II.both enthalpy and entropy increase III.ΔH is negative and ΔS is positive IV.both enthalpy and entropy decrease V.ΔH is positive and ΔS is negative

What is ΔrG°?

Which of the following has the highest entropy?

For the reaction What is DrSo?

What is ΔrG° at 25 °C? CO(g)+ 2 H2(g)→ CH3OH(g)ΔrH° = -90.7 kJ ΔrS° = -221 J/K

What is ΔrG°?

?rG ? is independent of temperature.

Calculate ΔrG° for the reaction Cu(s)+ H2O(g)→ CuO(s)+ H2(g)at 500 K.

What is ΔrG° at 25 °C? 2O3(g)→ 3 O2(g)ΔrH° = -284 kJ ΔrS° = 139 J/K

The enthalpy change for converting 1.00 mol of ice at -50.0 °C to water at 70.0 °C is The specific heats of ice,water,and steam are And Respectively.For O, = 6.01 kJ mol-1,and .

For the reaction I2(s)+ Cl2(g)→ 2 ICl(g),ΔrH = 36 kJ/mol,and ΔrS = 158.8 J/mol K at 25 °C.Calculate the temperature at which Keq is 4.0 × 103.

Predict whether ΔS is positive or negative for the following process: H2(g)+ 1/2 O2(g)→ H2O(g)

Which of the following best expresses the increase in entropy associated with melting and sublimation,respectively?

The entropy of a system always increases for a spontaneous process.

A spontaneous process will occur only if an external action is continually applied.

The entropy of a pure perfect crystal at 25 K is zero.

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

For the reaction PCl₅(g)→ PCl₃(g)+ Cl₂(g)at 298 K,K_eq = 1.87 × 10^-7,what is Δ_rG ° and is the reaction spontaneous?

The following reaction is exothermic. 2 N₂O(g)→ 2 N₂(g)+ O₂(g) This means the reaction:

What is Δ_rG°?

For the reaction What is D_rS^o?

What is Δ_rG° at 25 °C? CO(g)+ 2 H₂(g)→ CH₃OH(g)Δ_rH° = -90.7 kJ Δ_rS° = -221 J/K

What is Δ_rG°?

?_rG ? is independent of temperature.

Calculate Δ_rG° for the reaction Cu(s)+ H₂O(g)→ CuO(s)+ H₂(g)at 500 K.

What is Δ_rG° at 25 °C? 2O₃(g)→ 3 O₂(g)Δ_rH° = -284 kJ Δ_rS° = 139 J/K

The enthalpy change for converting 1.00 mol of ice at -50.0 °C to water at 70.0 °C is The specific heats of ice,water,and steam are And Respectively.For O, = 6.01 kJ mol^-1,and .

For the reaction I₂(s)+ Cl₂(g)→ 2 ICl(g),Δ_rH = 36 kJ/mol,and Δ_rS = 158.8 J/mol K at 25 °C.Calculate the temperature at which K_eq is 4.0 × 10³.

Predict whether ΔS is positive or negative for the following process: H₂(g)+ 1/2 O₂(g)→ H₂O(g)