Question 1

A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if   is ________ and   is ________.

Accepted Answer

A) +, + 
B) -, - 
C) +, - 
D) -, + 
E) +, 0 
A) +, + 
B) -, - 
C) +, - 
D) -, + 
E) +, 0

Question 2

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 3

The value of ΔG° at 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s,rhombic)+ 3O2 (g)→ 2SO3 (g)
Is ________ kJ/mol.

Accepted Answer

A) +740.8 
B) -370.4 
C) +370.4 
D) -740.8 
E) +185.2 
A) +740.8 
B) -370.4 
C) +370.4 
D) -740.8 
E) +185.2

Question 4

The combustion of hydrogen in the presence of excess oxygen yields liquid water: What is the value of ΔS° in J/K ∙ mol.for this reaction?

Accepted Answer

A) -405.5 
B) +405.5 
C) -265.7 
D) -326.3 
E) +265.7 
A) -405.5 
B) +405.5 
C) -265.7 
D) -326.3 
E) +265.7

Question 5

A reaction that is spontaneous as written ________.

Accepted Answer

A) is very rapid 
B) will proceed without outside intervention 
C) is also spontaneous in the reverse direction 
D) has an equilibrium position that lies far to the left 
E) is very slow 
A) is very rapid 
B) will proceed without outside intervention 
C) is also spontaneous in the reverse direction 
D) has an equilibrium position that lies far to the left 
E) is very slow

Question 6

The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements, CaCl2 (s)→ Ca (s)+ Cl2 (g)
Is ________ kJ/mol.

Accepted Answer

A) -795.8 
B) +795.8 
C) +763.7 
D) +748.1 
E) -748.1 
A) -795.8 
B) +795.8 
C) +763.7 
D) +748.1 
E) -748.1

Question 7

The normal boiling point of C2Cl3F3 is 47.6 °C and its molar enthalpy of vaporization is 27.49 kJ/mol.What is the change in entropy in the system in J/K when 28.6 grams of C2Cl3F3 vaporizes to a gas at the normal boiling point?

Accepted Answer

A) -13.1 
B) -4.19 
C) 4.19 
D) 13.1 
E) 27.5 
A) -13.1 
B) -4.19 
C) 4.19 
D) 13.1 
E) 27.5

Question 8

For a given reaction,ΔH = +74.6 kJ/mol,and the reaction is spontaneous at temperatures above the crossover temperature,   The value of   assuming that ΔH and ΔS do not vary with temperature.

Accepted Answer

A) 166 
B) 6020 
C) -166 
D) -6020 
E) 3.35 × 104 
A) 166 
B) 6020 
C) -166 
D) -6020 
E) 3.35 × 104

Question 9

The value of ΔS° for the catalytic hydrogenation of acetylene to ethane, C2H2 (g)+ 2H2 (g)→ C2H6 (g)
Is ________ J/K ∙ mol.

Accepted Answer

A) -76.0 
B) +440.9 
C) -232.5 
D) +232.5 
E) +28.7 
A) -76.0 
B) +440.9 
C) -232.5 
D) +232.5 
E) +28.7

Question 10

What is the ΔG° (kJ/mol)for the formation of silver chloride at 25 °C?
 Ksp = 1.8 × 10-10

Accepted Answer

Question 11

The value of ΔS° for the formation of phosphorous trichloride from its constituent elements, P2 (g)+ 3Cl2 (g)→ 2PCl3 (g)
Is ________ J/K ∙ mol.

Accepted Answer

A) -311.7 
B) +311.7 
C) -263.6 
D) +129.4 
E) -129.4 
A) -311.7 
B) +311.7 
C) -263.6 
D) +129.4 
E) -129.4

Question 12

The value of ΔS° for the decomposition of POCl3 into its constituent elements, 2POCl3 (g)→ P2 (g)+ O2 (g)+ 3Cl2 (g)
Is ________ J/K ∙ mol.

Accepted Answer

A) +771.0 
B) +442.0 
C) -321.0 
D) -771.0 
E) +321.0 
A) +771.0 
B) +442.0 
C) -321.0 
D) -771.0 
E) +321.0

Question 13

The value of ΔS° for the catalytic hydrogenation of acetylene to ethene, C2H2 (g)+ H2 (g)→ C2H4 (g)
Is ________ J/K∙ mol.

Accepted Answer

A) +18.6 
B) +550.8 
C) +112.0 
D) -112.0 
E) -18.6 
A) +18.6 
B) +550.8 
C) +112.0 
D) -112.0 
E) -18.6

Question 14

If ΔG° for a reaction is less than zero,then ________.

Accepted Answer

A) K > 1 B) K = 1 C) K < 1 D) K = 0 E) more information is needed. A) K > 1 B) K = 1 C) K < 1 D) K = 0 E) more information is needed.

Question 15

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 = k lnW 
E) S = Wk 
A) S = kW 
B) S =   
C) S =   
D) S = k lnW 
E) S = Wk

Question 16

Consider the reaction: FeO (s)+ Fe (s)+ O2(g)→ Fe2O3 (s)
Given the following table of thermodynamic data at 298 K:   The value K for the reaction at 25 °C is ________.

Accepted Answer

A) 370 
B) 5.9 × 104 
C) 3.8 × 10-14 
D) 7.1 × 1085 
E) 8.1 × 1019 
A) 370 
B) 5.9 × 104 
C) 3.8 × 10-14 
D) 7.1 × 1085 
E) 8.1 × 1019

Question 17

The equilibrium constant for a reaction is 0.38 at 25 °C.What is the value of ΔG° (kJ/mol)at this temperature?

Accepted Answer

A) 2.4 
B) -4.2 
C) 200 
D) 4.2 
E) More information is needed. 
A) 2.4 
B) -4.2 
C) 200 
D) 4.2 
E) More information is needed.

Question 18

Which of the following reactions would have a negative ΔS?

Accepted Answer

A) NH4Cl (s)→ NH3 (g)+ HCl (g) 
B) PbCl2 (s)→ Pb2+ (aq)+ 2Cl- (aq) 
C) 2C (s)+ O2 (g)→ 2CO2 (g) 
D) 2SO2 (g)+ O2 (g)→ 2SO3 (g) 
E) H2O (l)→ H2O (g) 
A) NH4Cl (s)→ NH3 (g)+ HCl (g) 
B) PbCl2 (s)→ Pb2+ (aq)+ 2Cl- (aq) 
C) 2C (s)+ O2 (g)→ 2CO2 (g) 
D) 2SO2 (g)+ O2 (g)→ 2SO3 (g) 
E) H2O (l)→ H2O (g)

Question 19

What is the change in entropy in the system in J/K when 112.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point? The normal boiling point of ethanol (C2H5OH)is 78.3 °C and its molar enthalpy of vaporization is 38.56 kJ/mol.

Accepted Answer

A) 382 
B) 1199 
C) -267 
D) -1199 
E) -382 
A) 382 
B) 1199 
C) -267 
D) -1199 
E) -382

Question 20

Consider the reaction: NH3 (g)+ HCl (g)→ NH4Cl (s)
Given the following table of thermodynamic data,   determine the temperature (in °C)above which the reaction is nonspontaneous.

Accepted Answer

A) This reaction is spontaneous at all temperatures. 
B) 618.1 
C) 432.8 
D) 345.0 
E) 1235 
A) This reaction is spontaneous at all temperatures. 
B) 618.1 
C) 432.8 
D) 345.0 
E) 1235

Exam 19: Chemical Thermodynamics

A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if is ________ and is ________.

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 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s,rhombic)+ 3O2 (g)→ 2SO3 (g) Is ________ kJ/mol.

The combustion of hydrogen in the presence of excess oxygen yields liquid water: What is the value of ΔS° in J/K ∙ mol.for this reaction?

A reaction that is spontaneous as written ________.

The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements, CaCl2 (s)→ Ca (s)+ Cl2 (g) Is ________ kJ/mol.

The normal boiling point of C2Cl3F3 is 47.6 °C and its molar enthalpy of vaporization is 27.49 kJ/mol.What is the change in entropy in the system in J/K when 28.6 grams of C2Cl3F3 vaporizes to a gas at the normal boiling point?

For a given reaction,ΔH = +74.6 kJ/mol,and the reaction is spontaneous at temperatures above the crossover temperature, The value of assuming that ΔH and ΔS do not vary with temperature.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethane, C2H2 (g)+ 2H2 (g)→ C2H6 (g) Is ________ J/K ∙ mol.

What is the ΔG° (kJ/mol)for the formation of silver chloride at 25 °C? Ksp = 1.8 × 10-10

The value of ΔS° for the formation of phosphorous trichloride from its constituent elements, P2 (g)+ 3Cl2 (g)→ 2PCl3 (g) Is ________ J/K ∙ mol.

The value of ΔS° for the decomposition of POCl3 into its constituent elements, 2POCl3 (g)→ P2 (g)+ O2 (g)+ 3Cl2 (g) Is ________ J/K ∙ mol.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethene, C2H2 (g)+ H2 (g)→ C2H4 (g) Is ________ J/K∙ mol.

If ΔG° for a reaction is less than zero,then ________.

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?

Consider the reaction: FeO (s)+ Fe (s)+ O2(g)→ Fe2O3 (s) Given the following table of thermodynamic data at 298 K: The value K for the reaction at 25 °C is ________.

The equilibrium constant for a reaction is 0.38 at 25 °C.What is the value of ΔG° (kJ/mol)at this temperature?

Which of the following reactions would have a negative ΔS?

What is the change in entropy in the system in J/K when 112.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point? The normal boiling point of ethanol (C2H5OH)is 78.3 °C and its molar enthalpy of vaporization is 38.56 kJ/mol.

Consider the reaction: NH3 (g)+ HCl (g)→ NH4Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C)above which the reaction is nonspontaneous.

Introduction: Matter, energy, and Measurement

Atoms, molecules, and Ions

Chemical Reactions and Reaction Stoichiometry

Reactions in Aqueous Solution

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

A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if is and is .

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 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s,rhombic)+ 3O₂ (g)→ 2SO₃ (g) Is ________ kJ/mol.

The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements, CaCl₂(s)→ Ca (s)+ Cl₂ (g) Is ________ kJ/mol.

The normal boiling point of C₂Cl₃F₃ is 47.6 °C and its molar enthalpy of vaporization is 27.49 kJ/mol.What is the change in entropy in the system in J/K when 28.6 grams of C₂Cl₃F₃ vaporizes to a gas at the normal boiling point?

The value of ΔS° for the catalytic hydrogenation of acetylene to ethane, C₂H₂ (g)+ 2H₂ (g)→ C₂H₆ (g) Is ________ J/K ∙ mol.

What is the ΔG° (kJ/mol)for the formation of silver chloride at 25 °C? K_sp = 1.8 × 10^-10

The value of ΔS° for the formation of phosphorous trichloride from its constituent elements, P₂ (g)+ 3Cl₂ (g)→ 2PCl₃ (g) Is ________ J/K ∙ mol.

The value of ΔS° for the decomposition of POCl₃ into its constituent elements, 2POCl₃ (g)→ P₂ (g)+ O₂ (g)+ 3Cl₂ (g) Is ________ J/K ∙ mol.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethene, C₂H₂ (g)+ H₂ (g)→ C₂H₄ (g) Is ________ J/K∙ mol.

Consider the reaction: FeO (s)+ Fe (s)+ O₂(g)→ Fe₂O₃ (s) Given the following table of thermodynamic data at 298 K: The value K for the reaction at 25 °C is ________.

What is the change in entropy in the system in J/K when 112.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point? The normal boiling point of ethanol (C₂H₅OH)is 78.3 °C and its molar enthalpy of vaporization is 38.56 kJ/mol.

Consider the reaction: NH₃ (g)+ HCl (g)→ NH₄Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C)above which the reaction is nonspontaneous.