Question 1

Which of the following statements is true?

Accepted Answer

A) Processes that are spontaneous in one direction are spontaneous in the opposite direction. 
B) Processes are spontaneous because they occur at an observable rate. 
C) Spontaneity can depend on the temperature. 
D) All of the statements are true. 
A) Processes that are spontaneous in one direction are spontaneous in the opposite direction. 
B) Processes are spontaneous because they occur at an observable rate. 
C) Spontaneity can depend on the temperature. 
D) All of the statements are true.

Question 2

The value of ΔG° at 25°C for the formation of phosphorous trichloride from its constituent elements, P2 (g)+ 3Cl2 (g)→ 2PCl3 (g)
Is __________ kJ/mol.

Accepted Answer

A) -539.2 
B) +539.2 
C) -642.9 
D) +642.9 
E) -373.3 
A) -539.2 
B) +539.2 
C) -642.9 
D) +642.9 
E) -373.3

Question 3

For the reaction 2C4H10 (g)+ 13O2 (g)→ 8CO2 (g)+ 10H2O (g)
ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is __________.

Accepted Answer

A) spontaneous at all temperatures 
B) spontaneous only at high temperature 
C) spontaneous only at low temperature 
D) nonspontaneous at all temperatures 
E) unable to determine without more information 
A) spontaneous at all temperatures 
B) spontaneous only at high temperature 
C) spontaneous only at low temperature 
D) nonspontaneous at all temperatures 
E) unable to determine without more information

Question 4

The equilibrium constant for a reaction is 0.35 at 25°C. What is the value of ΔG° (kJ/mol)at this temperature?

Accepted Answer

A) 2.6 
B) -4.2 
C) 220 
D) 4.2 
E) More information is needed. 
A) 2.6 
B) -4.2 
C) 220 
D) 4.2 
E) More information is needed.

Question 5

The value of ΔS° for the formation of calcium chloride from its constituent elements, Ca (s)+ Cl2 (g)→ CaCl2 (s)
Is __________ J/K∙ mol.

Accepted Answer

A) -104.6 
B) +104.6 
C) +369.0 
D) -159.8 
E) +159.8 
A) -104.6 
B) +104.6 
C) +369.0 
D) -159.8 
E) +159.8

Question 6

The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite)+ O2 (g)→ CO2(g)
Is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

Accepted Answer

A) +424.3 
B) +205.0 
C) -205.0 
D) -2.9 
E) +2.9 
A) +424.3 
B) +205.0 
C) -205.0 
D) -2.9 
E) +2.9

Question 7

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

Question 8

Which one of the following correctly indicates the relationship between the entropy of a system and the number of different arrangements, W, in the system?

Accepted Answer

A) S = kW 
B) S =   
C) S =   
D) S = klnW 
E) S = Wk 
A) S = kW 
B) S =   
C) S =   
D) S = klnW 
E) S = Wk

Question 9

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C2H4 (g)+ 3O2 (g)→ 2CO2 (g)+ 2H2O (l)
The value of ΔS° for this reaction is __________ J/K∙ mol.

Accepted Answer

A) -267.4 
B) -140.9 
C) -347.6 
D) +347.6 
E) +140.9 
A) -267.4 
B) -140.9 
C) -347.6 
D) +347.6 
E) +140.9

Question 10

Given the following table of thermodynamic data,   complete the following sentence. The vaporization of TiCl4 is __________.

Accepted Answer

A) spontaneous at all temperatures 
B) spontaneous at low temperature and nonspontaneous at high temperature 
C) nonspontaneous at low temperature and spontaneous at high temperature 
D) nonspontaneous at all temperatures 
E) not enough information given to draw a conclusion 
A) spontaneous at all temperatures 
B) spontaneous at low temperature and nonspontaneous at high temperature 
C) nonspontaneous at low temperature and spontaneous at high temperature 
D) nonspontaneous at all temperatures 
E) not enough information given to draw a conclusion

Question 11

The equilibrium position corresponds to which letter on the graph of G vs. f (course of reaction)below?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 12

The normal boiling point of water is 100.0°C and its molar enthalpy of vaporization is 40.67 kJ/mol. What is the change in entropy in the system in J/K when 39.3 grams of steam at 1 atm condenses to a liquid at the normal boiling point?

Accepted Answer

A) 88.8 
B) -88.8 
C) -238 
D) 373 
E) -40.7 
A) 88.8 
B) -88.8 
C) -238 
D) 373 
E) -40.7

Question 13

Consider the reaction: Ag+ (aq)+ Cl- (aq)→ AgCl (s)
Given the following table of thermodynamic data at 298 K:   The value of K for the reaction at 25°C is __________.

Accepted Answer

A) 810 
B) 5.3 × 109 
C) 1.8 × 104 
D) 3.7 × 1010 
E) 1.9 × 10-10 
A) 810 
B) 5.3 × 109 
C) 1.8 × 104 
D) 3.7 × 1010 
E) 1.9 × 10-10

Question 14

Which one of the following is always positive when a spontaneous process occurs?

Accepted Answer

A) ΔSsystem 
B) ΔSsurroundings 
C) ΔSuniverse 
D) ΔHuniverse 
E) ΔHsurroundings 
A) ΔSsystem 
B) ΔSsurroundings 
C) ΔSuniverse 
D) ΔHuniverse 
E) ΔHsurroundings

Question 15

The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s, rhombic)+ 3O2( g)→ 2SO3 (g)
Is __________ kJ/mol.

Accepted Answer

A) +790.4 
B) -790.4 
C) +395.2 
D) -395.2 
E) +105.1 
A) +790.4 
B) -790.4 
C) +395.2 
D) -395.2 
E) +105.1

Question 16

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C2H4 (g)+ H2(g)→ C2H6 (g)
Is __________ J/K∙ mol.

Accepted Answer

A) -101.9 
B) -120.5 
C) -232.5 
D) +112.0 
E) +101.9 
A) -101.9 
B) -120.5 
C) -232.5 
D) +112.0 
E) +101.9

Question 17

Which one of the following processes produces a decrease of the entropy of the system?

Accepted Answer

A) dissolving sodium chloride in water 
B) sublimation of naphthalene 
C) dissolving oxygen in water 
D) boiling of alcohol 
E) explosion of nitroglycerine 
A) dissolving sodium chloride in water 
B) sublimation of naphthalene 
C) dissolving oxygen in water 
D) boiling of alcohol 
E) explosion of nitroglycerine

Question 18

The value of ΔH° for the decomposition of calcium chloride into its constituent elements, CaCl2 (s)→ Ca (s)+ Cl2 (g)
Is __________ kJ/mol.

Accepted Answer

A) -0.00 
B) -397.9 
C) +397.9 
D) -795.8 
E) +795.8 
A) -0.00 
B) -397.9 
C) +397.9 
D) -795.8 
E) +795.8

Question 19

Of the following, the entropy of __________ is the largest.

Accepted Answer

A) HCl (l) 
B) HCl (s) 
C) HCl (g) 
D) HBr (g) 
E) HI (g) 
A) HCl (l) 
B) HCl (s) 
C) HCl (g) 
D) HBr (g) 
E) HI (g)

Question 20

The value of ΔH° for the formation of POCl3 from its constituent elements, P2 (g)+ O2 (g)+ 3Cl2 (g)→ 2POCl3 (g)
Is __________ kJ/mol.

Accepted Answer

A) -1228.7 
B) -397.7 
C) -686.5 
D) +1228.7 
E) +686.5 
A) -1228.7 
B) -397.7 
C) -686.5 
D) +1228.7 
E) +686.5

Exam 19: Chemical Thermodynamics

Which of the following statements is true?

The value of ΔG° at 25°C for the formation of phosphorous trichloride from its constituent elements, P2 (g)+ 3Cl2 (g)→ 2PCl3 (g) Is __________ kJ/mol.

For the reaction 2C4H10 (g)+ 13O2 (g)→ 8CO2 (g)+ 10H2O (g) ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is __________.

The equilibrium constant for a reaction is 0.35 at 25°C. What is the value of ΔG° (kJ/mol)at this temperature?

The value of ΔS° for the formation of calcium chloride from its constituent elements, Ca (s)+ Cl2 (g)→ CaCl2 (s) Is __________ J/K∙ mol.

The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite)+ O2 (g)→ CO2(g) Is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

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.

Which one of the following correctly indicates the relationship between the entropy of a system and the number of different arrangements, W, in the system?

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C2H4 (g)+ 3O2 (g)→ 2CO2 (g)+ 2H2O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

Given the following table of thermodynamic data, complete the following sentence. The vaporization of TiCl4 is __________.

The equilibrium position corresponds to which letter on the graph of G vs. f (course of reaction)below?

The normal boiling point of water is 100.0°C and its molar enthalpy of vaporization is 40.67 kJ/mol. What is the change in entropy in the system in J/K when 39.3 grams of steam at 1 atm condenses to a liquid at the normal boiling point?

Consider the reaction: Ag+ (aq)+ Cl- (aq)→ AgCl (s) Given the following table of thermodynamic data at 298 K: The value of K for the reaction at 25°C is __________.

Which one of the following is always positive when a spontaneous process occurs?

The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s, rhombic)+ 3O2( g)→ 2SO3 (g) Is __________ kJ/mol.

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C2H4 (g)+ H2(g)→ C2H6 (g) Is __________ J/K∙ mol.

Which one of the following processes produces a decrease of the entropy of the system?

The value of ΔH° for the decomposition of calcium chloride into its constituent elements, CaCl2 (s)→ Ca (s)+ Cl2 (g) Is __________ kJ/mol.

Of the following, the entropy of __________ is the largest.

The value of ΔH° for the formation of POCl3 from its constituent elements, P2 (g)+ O2 (g)+ 3Cl2 (g)→ 2POCl3 (g) Is __________ kJ/mol.

Introduction: Matter and Measurement

Atoms, Molecules, and Ions

Stoichiometry: Calculations With Chemical Formulas and Equations

Aqueous Reactions and Solution Stoichiometry

Thermochemistry

Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Gases

Liquids and Intermolecular Forces

Solids and Modern Materials

Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

Chemistry of the Environment

Electrochemistry

Nuclear Chemistry

Chemistry of the Nonmetals

Transition Metals and Coordination Chemistry

The Chemistry of Life: Organic and Biological Chemistry

Filters

The value of ΔG° at 25°C for the formation of phosphorous trichloride from its constituent elements, P₂(g)+ 3Cl₂ (g)→ 2PCl₃ (g) Is __________ kJ/mol.

For the reaction 2C₄H₁₀ (g)+ 13O₂ (g)→ 8CO₂ (g)+ 10H₂O (g) ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is __________.

The value of ΔS° for the formation of calcium chloride from its constituent elements, Ca (s)+ Cl₂ (g)→ CaCl₂(s) Is __________ J/K∙ mol.

The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite)+ O₂ (g)→ CO₂(g) Is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

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.

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C₂H₄ (g)+ 3O₂ (g)→ 2CO₂ (g)+ 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

Given the following table of thermodynamic data, complete the following sentence. The vaporization of TiCl₄ is __________.

Consider the reaction: Ag⁺ (aq)+ Cl^- (aq)→ AgCl (s) Given the following table of thermodynamic data at 298 K: The value of K for the reaction at 25°C is __________.

The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s, rhombic)+ 3O₂( g)→ 2SO₃ (g) Is __________ kJ/mol.

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C₂H₄(g)+ H₂(g)→ C₂H₆(g) Is __________ J/K∙ mol.

The value of ΔH° for the decomposition of calcium chloride into its constituent elements, CaCl₂ (s)→ Ca (s)+ Cl₂ (g) Is __________ kJ/mol.

The value of ΔH° for the formation of POCl₃ from its constituent elements, P₂ (g)+ O₂ (g)+ 3Cl₂ (g)→ 2POCl₃ (g) Is __________ kJ/mol.