Question 1

The standard free energy of formation of AgI(s)is -66.2 kJ/mol.ΔrG° for the reaction 2AgI(s)→ 2Ag(s)+ I2(s)is:

Accepted Answer

A)  132.4 kJ 
B)  66.2 kJ 
C)  -132.4 kJ 
D)  -66.2 kJ 
E)  800 KJ 
A)  132.4 kJ 
B)  66.2 kJ 
C)  -132.4 kJ 
D)  -66.2 kJ 
E)  800 KJ A

Question 2

Which of the following represents the change in entropy for a system going from 142 possible microstates to 830 possible microstates? (k = 1.381 × 10-23 J/K)

Accepted Answer

A)    J/K 
B)    J/K 
C)  −   J/K 
D)    J/K 
E)  −   J/K 
A)    J/K 
B)    J/K 
C)  −   J/K 
D)    J/K 
E)  −   J/K D

Question 3

At what temperatures will a reaction be spontaneous if ΔrH° = +117 kJ and ΔrS° = -35 J/K?

Accepted Answer

A)  All temperatures below 94.1 K 
B)  Temperatures between 12.7 K and 135 K 
C)  All temperatures above 94.1 K 
D)  The reaction will be spontaneous at any temperature. 
E)  The reaction will never be spontaneous. 
A)  All temperatures below 94.1 K 
B)  Temperatures between 12.7 K and 135 K 
C)  All temperatures above 94.1 K 
D)  The reaction will be spontaneous at any temperature. 
E)  The reaction will never be spontaneous. E

Question 4

Which of the following linear chain alcohols is likely to have the highest standard entropy in the liquid state?

Accepted Answer

A)  CH3OH 
B)  CH3CH2OH 
C)  CH3CH2CH2OH 
D)  CH3CH2CH2CH2OH 
E)  CH3CH2CH2CH2CH2OH 
A)  CH3OH 
B)  CH3CH2OH 
C)  CH3CH2CH2OH 
D)  CH3CH2CH2CH2OH 
E)  CH3CH2CH2CH2CH2OH

Question 5

What is the equilibrium constant for the reaction below at 298 K? 2C(s)+ 3H2(g)→ C2H6(g)
Given: ΔrH° = -84.68 kJ; ΔrS° = -173.8 J/K at 298 K.(R = 8.314 J/K⋅mol)

Accepted Answer

A)  5.8 × 105 
B)  1.0 × 10−5 
C)  8.6 × 10-10 
D)  1.7 × 10-6 
E)  7.0 × 1014 
A)  5.8 × 105 
B)  1.0 × 10−5 
C)  8.6 × 10-10 
D)  1.7 × 10-6 
E)  7.0 × 1014

Question 6

Thermodynamics can be used to determine all of the following except _____.

Accepted Answer

A)  the temperature at which a reaction is spontaneous 
B)  the extent to which a reaction occurs 
C)  the direction in which a reaction is spontaneous 
D)  the rate of reaction 
E)  the entropy change of a reaction 
A)  the temperature at which a reaction is spontaneous 
B)  the extent to which a reaction occurs 
C)  the direction in which a reaction is spontaneous 
D)  the rate of reaction 
E)  the entropy change of a reaction

Question 7

Calculate the enthalpy of vaporization of water at its normal boiling point.ΔS° [H2O(   )] = 69.9 J/K⋅mol and ΔS° [H2O(g)] = 188.8 J/K⋅mol.

Accepted Answer

Question 8

Which of the following is the first law of thermodynamics?

Accepted Answer

A)  In a spontaneous process,the entropy of the universe increases. 
B)  There is no disorder in a perfect crystal at 0 K. 
C)  The total energy of the universe is always decreasing. 
D)  Energy cannot be created or destroyed. 
E)  mass and energy are conserved in all chemical reactions. 
A)  In a spontaneous process,the entropy of the universe increases. 
B)  There is no disorder in a perfect crystal at 0 K. 
C)  The total energy of the universe is always decreasing. 
D)  Energy cannot be created or destroyed. 
E)  mass and energy are conserved in all chemical reactions.

Question 9

What is the sign of ΔH (system)and ΔS (system)if a chemical reaction is spontaneous only at lower temperatures under standard conditions?

Accepted Answer

A)  ΔH (system)is negative,and ΔS (system)is negative. 
B)  ΔH (system)is positive,and ΔS (system)is positive. 
C)  ΔH (system)is positive,and ΔS (system)is negative. 
D)  ΔH (system)is negative,and ΔS (system)is positive. 
E)  None of these 
A)  ΔH (system)is negative,and ΔS (system)is negative. 
B)  ΔH (system)is positive,and ΔS (system)is positive. 
C)  ΔH (system)is positive,and ΔS (system)is negative. 
D)  ΔH (system)is negative,and ΔS (system)is positive. 
E)  None of these

Question 10

Using the given data,determine ΔrG° at 298 K for the precipitation reaction below. Ag+(aq)+Br−(aq)→ AgBr(s)
Substance
ΔfG°(kJ/mol)at 298 K
Br−(aq)
-104.0
Ag+(aq)
77)12
AgBr(s)
-96)9

Accepted Answer

A)  -70.0 kJ/mol-rxn 
B)  -123.8 kJ/mol-rxn 
C)  70.0 kJ/mol-rxn 
D)  123.8 kJ/mol-rxn 
E)  84.2 kJ/mol-rxn 
A)  -70.0 kJ/mol-rxn 
B)  -123.8 kJ/mol-rxn 
C)  70.0 kJ/mol-rxn 
D)  123.8 kJ/mol-rxn 
E)  84.2 kJ/mol-rxn

Question 11

Calculate ΔrG° at 25.0 °C for the reaction below. 2 Na(s)+ 2 H2O(   )→ 2 NaOH(aq)+ H2(g)
Given: ΔrH° = −366.6 kJ/mol-rxn and ΔrS° = −154.2 J/K⋅mol-rxn.

Accepted Answer

A)  -371.2 kJ/mol-rxn 
B)  -320.6 kJ/mol-rxn 
C)  -215.4 kJ/mol-rxn 
D)  +371.2 kJ/mol-rxn 
E)  +4634.9 kJ/mol-rxn 
A)  -371.2 kJ/mol-rxn 
B)  -320.6 kJ/mol-rxn 
C)  -215.4 kJ/mol-rxn 
D)  +371.2 kJ/mol-rxn 
E)  +4634.9 kJ/mol-rxn

Question 12

Which of the following statements about entropy is true?

Accepted Answer

A)  The entropy of a substance will increase on going from a solid to a liquid to a gas. 
B)  The entropy of any substance increases as the temperature is lowered. 
C)  The entropy of a gas is independent of the volume of the gas. 
D)  The entropy of a gas decreases with an increase in volume. 
E)  The entropy of a substance increases with a decrease in the number of moles. 
A)  The entropy of a substance will increase on going from a solid to a liquid to a gas. 
B)  The entropy of any substance increases as the temperature is lowered. 
C)  The entropy of a gas is independent of the volume of the gas. 
D)  The entropy of a gas decreases with an increase in volume. 
E)  The entropy of a substance increases with a decrease in the number of moles.

Question 13

A flask containing helium gas is released into a closed room.Which of the following ideas concerning entropy is/are true?

Accepted Answer

A)  ΔS(system)> 0 
B)  Matter is dispersed. 
C)  ΔS(universe)> 0 
D)  This process is spontaneous. 
E)  All of these statements are true. 
A)  ΔS(system)> 0 
B)  Matter is dispersed. 
C)  ΔS(universe)> 0 
D)  This process is spontaneous. 
E)  All of these statements are true.

Question 14

Which of the following is true of the deposition of a gaseous substance?

Accepted Answer

A) ΔS° = 0 and ΔH° = 0. B) ΔS° > 0 and ΔH° > 0. C) ΔS° 0. D) ΔS° 0 and ΔH° < 0. A) ΔS° = 0 and ΔH° = 0. B) ΔS° > 0 and ΔH° > 0. C) ΔS° 0. D) ΔS° 0 and ΔH° < 0.

Question 15

In any chemical process,energy must be conserved.This is the _____ law of thermodynamics.

Accepted Answer

The answer of In any chemical process,energy must be conserved.This...

Question 16

Which of the following is the second law of thermodynamics?

Accepted Answer

A)  In a spontaneous process,the entropy of the universe increases. 
B)  There is no disorder in a perfect crystal at 0 K. 
C)  The total energy of the universe is always increasing. 
D)  The total energy of the universe is constant. 
E)  Mass and energy are conserved in all chemical reactions. 
A)  In a spontaneous process,the entropy of the universe increases. 
B)  There is no disorder in a perfect crystal at 0 K. 
C)  The total energy of the universe is always increasing. 
D)  The total energy of the universe is constant. 
E)  Mass and energy are conserved in all chemical reactions.

Question 17

Which of the following is correct for the condensation of gaseous oxygen at -188 °C? (The normal boiling point of oxygen is -183 °C.)

Accepted Answer

A)  ΔH  0,and ΔG > 0. 
B)  ΔH 0. 
C)  ΔH > 0,ΔS  0,ΔS > 0,and ΔG > 0. 
A)  ΔH  0,and ΔG > 0. 
B)  ΔH 0. 
C)  ΔH > 0,ΔS  0,ΔS > 0,and ΔG > 0.

Question 18

For which of the following reactions will the entropy of a system decrease?

Accepted Answer

A)  2 NH3(g)→ N2(g)+ 3 H2(g) 
B)  2 C(s)+ O2(g)→ 2 CO(g) 
C)  CaCO3(s)→ CaO(s)+ CO2(g) 
D)  2 NO2(g)→ N2O4(g) 
E)  NaOH(s)→ Na+(aq)+ OH-(aq) 
A)  2 NH3(g)→ N2(g)+ 3 H2(g) 
B)  2 C(s)+ O2(g)→ 2 CO(g) 
C)  CaCO3(s)→ CaO(s)+ CO2(g) 
D)  2 NO2(g)→ N2O4(g) 
E)  NaOH(s)→ Na+(aq)+ OH-(aq)

Question 19

The dissolution of ammonium nitrate occurs spontaneously in water at 25 °C.As ammonium nitrate dissolves,the temperature of the water decreases.What are the signs of ΔrH,ΔrS,and ΔrG for this process?

Accepted Answer

A)  ΔrH > 0,ΔrS rG > 0 
B)  ΔrH > 0,ΔrS > 0,and ΔrG > 0 
C)  ΔrH > 0,ΔrS > 0,and ΔrG rH rS rG rH rS > 0,and ΔrG > 0 
A)  ΔrH > 0,ΔrS rG > 0 
B)  ΔrH > 0,ΔrS > 0,and ΔrG > 0 
C)  ΔrH > 0,ΔrS > 0,and ΔrG rH rS rG rH rS > 0,and ΔrG > 0

Question 20

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K. NH4NO3(s)   NH4NO3(aq)
Which of the following is the equilibrium constant for the reaction? (R = 8.314 J/K⋅mol)

Accepted Answer

A)  1.9 × 10-3 
B)  6.6 × 10-2 
C)  1.0 
D)  15 
E)  5.2 × 102 
A)  1.9 × 10-3 
B)  6.6 × 10-2 
C)  1.0 
D)  15 
E)  5.2 × 102

Exam 19: Principles of Chemical Reactivity: Entropy and Free Energy

The standard free energy of formation of AgI(s)is -66.2 kJ/mol.ΔrG° for the reaction 2AgI(s)→ 2Ag(s)+ I2(s)is:

Which of the following represents the change in entropy for a system going from 142 possible microstates to 830 possible microstates? (k = 1.381 × 10-23 J/K)

At what temperatures will a reaction be spontaneous if ΔrH° = +117 kJ and ΔrS° = -35 J/K?

Which of the following linear chain alcohols is likely to have the highest standard entropy in the liquid state?

What is the equilibrium constant for the reaction below at 298 K? 2C(s)+ 3H2(g)→ C2H6(g) Given: ΔrH° = -84.68 kJ; ΔrS° = -173.8 J/K at 298 K.(R = 8.314 J/K⋅mol)

Thermodynamics can be used to determine all of the following except _____.

Calculate the enthalpy of vaporization of water at its normal boiling point.ΔS° [H2O( )] = 69.9 J/K⋅mol and ΔS° [H2O(g)] = 188.8 J/K⋅mol.

Which of the following is the first law of thermodynamics?

What is the sign of ΔH (system)and ΔS (system)if a chemical reaction is spontaneous only at lower temperatures under standard conditions?

Using the given data,determine ΔrG° at 298 K for the precipitation reaction below. Ag+(aq)+Br−(aq)→ AgBr(s) Substance ΔfG°(kJ/mol)at 298 K Br−(aq) -104.0 Ag+(aq) 77)12 AgBr(s) -96)9

Calculate ΔrG° at 25.0 °C for the reaction below. 2 Na(s)+ 2 H2O( )→ 2 NaOH(aq)+ H2(g) Given: ΔrH° = −366.6 kJ/mol-rxn and ΔrS° = −154.2 J/K⋅mol-rxn.

Which of the following statements about entropy is true?

A flask containing helium gas is released into a closed room.Which of the following ideas concerning entropy is/are true?

Which of the following is true of the deposition of a gaseous substance?

In any chemical process,energy must be conserved.This is the _____ law of thermodynamics.

Which of the following is the second law of thermodynamics?

Which of the following is correct for the condensation of gaseous oxygen at -188 °C? (The normal boiling point of oxygen is -183 °C.)

For which of the following reactions will the entropy of a system decrease?

The dissolution of ammonium nitrate occurs spontaneously in water at 25 °C.As ammonium nitrate dissolves,the temperature of the water decreases.What are the signs of ΔrH,ΔrS,and ΔrG for this process?

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K. NH4NO3(s) NH4NO3(aq) Which of the following is the equilibrium constant for the reaction? (R = 8.314 J/K⋅mol)

Basic Concepts of Chemistry

Lets Review: The Tools of Quantitative Chemistry

Atoms, molecules, and Ions

Chemical Reactions

Stoichiometry: Quantitative Information About Chemical Reactions

Principles of Chemical Reactivity: Energy and Chemical Reactions

The Structure of Atoms

The Structure of Atoms and Periodic Trends

Bonding and Molecular Structure

Bonding and Molecular Structure Orbital Hybridization and Molecular Orbitals

Gases and Their Properties

Intermolecular Forces and Liquids

The Solid State

Solutions and Their Behavior

Chemical Kinetics: the Rates of Chemical Reactions

Principles of Chemical Reactivity: Equilibria

Principles of Chemical Reactivity: the Chemistry of Acids and Bases

Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

Principles of Chemical Reactivity: Electron Transfer Reactions

Environmental Chemistry: Earths Environment, energy, and Sustainability

The Chemistry of the Main Group Elements

The Chemistry of the Transition Elements

Carbon: Not Just Another Element

Biochemistry

Nuclear Chemistry

Filters

The standard free energy of formation of AgI(s)is -66.2 kJ/mol.Δ_rG° for the reaction 2AgI(s)→ 2Ag(s)+ I₂(s)is:

Which of the following represents the change in entropy for a system going from 142 possible microstates to 830 possible microstates? (k = 1.381 × 10^-23 J/K)

At what temperatures will a reaction be spontaneous if Δ_rH° = +117 kJ and Δ_rS° = -35 J/K?

What is the equilibrium constant for the reaction below at 298 K? 2C(s)+ 3H₂(g)→ C₂H₆(g) Given: Δ_rH° = -84.68 kJ; Δ_rS° = -173.8 J/K at 298 K.(R = 8.314 J/K⋅mol)

Calculate the enthalpy of vaporization of water at its normal boiling point.ΔS° [H₂O( )] = 69.9 J/K⋅mol and ΔS° [H₂O(g)] = 188.8 J/K⋅mol.

Using the given data,determine ΔrG° at 298 K for the precipitation reaction below. Ag⁺(aq)+Br−(aq)→ AgBr(s) Substance ΔfG°(kJ/mol)at 298 K Br−(aq) -104.0 Ag⁺(aq) 77)12 AgBr(s) -96)9

Calculate Δ_rG° at 25.0 °C for the reaction below. 2 Na(s)+ 2 H₂O( )→ 2 NaOH(aq)+ H₂(g) Given: Δ_rH° = −366.6 kJ/mol-rxn and Δ_rS° = −154.2 J/K⋅mol-rxn.

The dissolution of ammonium nitrate occurs spontaneously in water at 25 °C.As ammonium nitrate dissolves,the temperature of the water decreases.What are the signs of Δ_rH,Δ_rS,and Δ_rG for this process?

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K. NH₄NO₃(s) NH₄NO₃(aq) Which of the following is the equilibrium constant for the reaction? (R = 8.314 J/K⋅mol)