Question 1

When a sky diver free-falls through the air, the process is

Accepted Answer

A)  non-spontaneous because he is accelerating due to the force applied by gravity. 
B)  non-spontaneous because he is losing potential energy. 
C)  non-spontaneous, if he had planned the jump for two weeks. 
D)  spontaneous. 
E)  in equilibrium. 
A)  non-spontaneous because he is accelerating due to the force applied by gravity. 
B)  non-spontaneous because he is losing potential energy. 
C)  non-spontaneous, if he had planned the jump for two weeks. 
D)  spontaneous. 
E)  in equilibrium.

Question 2

A certain process has F1F1F1S1F1F1F10Suniv > 0 at 25°C. What does one know about the process?

Accepted Answer

A)  It is exothermic. 
B)  It is endothermic. 
C)  It is spontaneous at 25°C. 
D)  It will move rapidly toward equilibrium. 
E)  none of the above 
A)  It is exothermic. 
B)  It is endothermic. 
C)  It is spontaneous at 25°C. 
D)  It will move rapidly toward equilibrium. 
E)  none of the above

Question 3

Which of the following results in a decrease in the entropy of the system?

Accepted Answer

A)  O2(g), 300 K F1F1F1S1F1F1F10 O2(g), 400 K 
B)  H2O(s), 0°C F1F1F1S1F1F1F10 H2O(l), 0°C 
C)  N2(g), 25°C F1F1F1S1F1F1F10 N2(aq), 25°C 
D)  NH3(l), -34.5°C F1F1F1S1F1F1F10 NH3(g), -34.5°C 
E)  2H2O2(g) F1F1F1S1F1F1F10 2H2O(g) + O2(g) 
A)  O2(g), 300 K F1F1F1S1F1F1F10 O2(g), 400 K 
B)  H2O(s), 0°C F1F1F1S1F1F1F10 H2O(l), 0°C 
C)  N2(g), 25°C F1F1F1S1F1F1F10 N2(aq), 25°C 
D)  NH3(l), -34.5°C F1F1F1S1F1F1F10 NH3(g), -34.5°C 
E)  2H2O2(g) F1F1F1S1F1F1F10 2H2O(g) + O2(g)

Question 4

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25°C.

Accepted Answer

A)  CO(g), CO2(g) 
B)  NaCl(s), NaCl(aq) 
C)  H2S(g), H2S(aq) 
D)  Li(s), Pb(s) 
E)  H2(g), H2O(g) 
A)  CO(g), CO2(g) 
B)  NaCl(s), NaCl(aq) 
C)  H2S(g), H2S(aq) 
D)  Li(s), Pb(s) 
E)  H2(g), H2O(g)

Question 5

"A diamond is forever" is one of the most successful advertising slogans of all time. But is it true? For the reaction shown below, calculate the standard free energy change at 298K and determine whether or not a diamond is "forever". C(diamond) F1F1F1S1F1F1F10 C(graphite)
Data: F1F1F1S1F1F1F10Hf°(diamond) = 1.895 kJ/mol; S°(diamond) = 2.337 J mol-1 K-1;
S°(graphite) = 5.740 J mol-1K-1.

Accepted Answer

A)  .F1F1F1S1F1F1F10G° = 2.19 kJ; forever 
B)  .F1F1F1S1F1F1F10G° = -1.90 kJ; not forever 
C)  .F1F1F1S1F1F1F10G° = -2.90 kJ; not forever 
D)  .F1F1F1S1F1F1F10G° = 1.90 kJ; forever 
E)  .F1F1F1S1F1F1F10G° = < -1000 kJ; not forever 
A)  .F1F1F1S1F1F1F10G° = 2.19 kJ; forever 
B)  .F1F1F1S1F1F1F10G° = -1.90 kJ; not forever 
C)  .F1F1F1S1F1F1F10G° = -2.90 kJ; not forever 
D)  .F1F1F1S1F1F1F10G° = 1.90 kJ; forever 
E)  .F1F1F1S1F1F1F10G° = < -1000 kJ; not forever

Question 6

Calculate the equilibrium constant at 25°C for the reaction of methane with water to form carbon dioxide and hydrogen. The data refer to

Accepted Answer

A)  8.2 × 1019 
B)  0.96 
C)  0.58 
D)  1.2 × 10-20 
E)  1.4 × 10-46 
A)  8.2 × 1019 
B)  0.96 
C)  0.58 
D)  1.2 × 10-20 
E)  1.4 × 10-46

Question 7

Which relationship or statement best describes F1F1F1S1F1F1F10S° for the following reaction? 
O3(g) + NO(g) F1F1F1S1F1F1F10 O2(g) + NO2(g)

Accepted Answer

A)  .F1F1F1S1F1F1F10S° F1F1F1S1F1F1F10 0 
B)  .F1F1F1S1F1F1F10S°  0 
D)  .F1F1F1S1F1F1F10S° = F1F1F1S1F1F1F10H°/T 
E)  More information is needed to make a reasonable prediction. 
A)  .F1F1F1S1F1F1F10S° F1F1F1S1F1F1F10 0 
B)  .F1F1F1S1F1F1F10S°  0 
D)  .F1F1F1S1F1F1F10S° = F1F1F1S1F1F1F10H°/T 
E)  More information is needed to make a reasonable prediction.

Question 8

For a process with F1F1F1S1F1F1F10S < 0, which one of the following statements is correct?

Accepted Answer

A)  The process will definitely be spontaneous if F1F1F1S1F1F1F10H surr > 0. 
A)  The process will definitely be spontaneous if F1F1F1S1F1F1F10H surr > 0.

Question 9

Which relationship or statement best describes F1F1F1S1F1F1F10S° for the following reaction? 
2H2S(g) + 3O2(g) F1F1F1S1F1F1F10 2H2O(g) + 2SO2(g)

Accepted Answer

A)  .F1F1F1S1F1F1F10S°  F1F1F1S1F1F1F10 0 
B)  .F1F1F1S1F1F1F10S°  0 
D)  .F1F1F1S1F1F1F10S° = F1F1F1S1F1F1F10H°/T 
E)  More information is needed to make a reasonable prediction. 
A)  .F1F1F1S1F1F1F10S°  F1F1F1S1F1F1F10 0 
B)  .F1F1F1S1F1F1F10S°  0 
D)  .F1F1F1S1F1F1F10S° = F1F1F1S1F1F1F10H°/T 
E)  More information is needed to make a reasonable prediction.

Question 10

Consider the following quantities used in thermodynamics: E, H, q, w, S, G. How many of them are state functions?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
E)  4 
A)  0 
B)  1 
C)  2 
D)  3 
E)  4

Question 11

The term microstate refers to the energy state of a single molecule in a system of many molecules.

Accepted Answer

A) True 
 B)False

Question 12

In some spontaneous processes, the entropy of the surroundings decreases.

Accepted Answer

A) True 
 B)False

Question 13

For the reaction of xenon and fluorine gases to form solid XeF4, F1F1F1S1F1F1F10H° = -251 kJ and F1F1F1S1F1F1F10G° = -121 kJ at 25°C. Calculate F1F1F1S1F1F1F10S° for the reaction.

Accepted Answer

F1F1F1S1F

Question 14

In which one of the following pairs will the first system have a higher entropy than the second? Assume P and T are the same for each pair, unless stated otherwise.

Accepted Answer

A)  1 mole He(g); 1 mole Kr(g) 
B)  1 mole O2(g); 2 mole O(g) 
C)  1 mole CH4(g); 1 mole C2H6(g) 
D)  1 mole Xe(g) at 1 atmosphere; 1 mole Xe(g) at 0.5 atmosphere 
E)  20 one-dollar bills distributed randomly among 20 people; 20 one-dollar bills distributed randomly among 10 people 
A)  1 mole He(g); 1 mole Kr(g) 
B)  1 mole O2(g); 2 mole O(g) 
C)  1 mole CH4(g); 1 mole C2H6(g) 
D)  1 mole Xe(g) at 1 atmosphere; 1 mole Xe(g) at 0.5 atmosphere 
E)  20 one-dollar bills distributed randomly among 20 people; 20 one-dollar bills distributed randomly among 10 people

Question 15

A reaction is proceeding toward equilibrium. At a certain stage, the concentrations of reactants and products are such that F1F1F1S1F1F1F10G = F1F1F1S1F1F1F10G°. What conclusion can reasonably be drawn about the reaction at this time?

Accepted Answer

A) K > Q B) K < Q C) K = Q D) K = 1 E) Q = 1 A) K > Q B) K < Q C) K = Q D) K = 1 E) Q = 1

Question 16

In a spontaneous process, the entropy of the system always increases.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following is always true for an exothermic process?

Accepted Answer

A) q sys > 0, F1F1F1S1F1F1F10Ssurr sys surr > 0 C) q sys surr sys > 0, F1F1F1S1F1F1F10Ssurr > 0 E) w < 0 A) q sys > 0, F1F1F1S1F1F1F10Ssurr sys surr > 0 C) q sys surr sys > 0, F1F1F1S1F1F1F10Ssurr > 0 E) w < 0

Question 18

Which one of the following phase changes decreases the entropy of the system?

Accepted Answer

A)  melting 
B)  heating a gas 
C)  vaporization 
D)  condensation 
E)  sublimation 
A)  melting 
B)  heating a gas 
C)  vaporization 
D)  condensation 
E)  sublimation

Question 19

The entropy of one mole of oxygen gas in a 0.5-L container is less than it would be in a 22.4-L container at the same temperature.

Accepted Answer

A) True 
 B)False

Question 20

The free energy of a perfect crystal at absolute zero, is zero.

Accepted Answer

A) True 
 B)False

Exam 20: Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

When a sky diver free-falls through the air, the process is

A certain process has Suniv > 0 at 25°C. What does one know about the process?

Which of the following results in a decrease in the entropy of the system?

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25°C.

Calculate the equilibrium constant at 25°C for the reaction of methane with water to form carbon dioxide and hydrogen. The data refer to

Which relationship or statement best describes S° for the following reaction? O3(g) + NO(g)  O2(g) + NO2(g)

For a process with S < 0, which one of the following statements is correct?

Which relationship or statement best describes S° for the following reaction? 2H2S(g) + 3O2(g)  2H2O(g) + 2SO2(g)

Consider the following quantities used in thermodynamics: E, H, q, w, S, G. How many of them are state functions?

The term microstate refers to the energy state of a single molecule in a system of many molecules.

In some spontaneous processes, the entropy of the surroundings decreases.

For the reaction of xenon and fluorine gases to form solid XeF4, H° = -251 kJ and G° = -121 kJ at 25°C. Calculate S° for the reaction.

In which one of the following pairs will the first system have a higher entropy than the second? Assume P and T are the same for each pair, unless stated otherwise.

A reaction is proceeding toward equilibrium. At a certain stage, the concentrations of reactants and products are such that G = G°. What conclusion can reasonably be drawn about the reaction at this time?

In a spontaneous process, the entropy of the system always increases.

Which of the following is always true for an exothermic process?

Which one of the following phase changes decreases the entropy of the system?

The entropy of one mole of oxygen gas in a 0.5-L container is less than it would be in a 22.4-L container at the same temperature.

The free energy of a perfect crystal at absolute zero, is zero.

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

The Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main Group Elements: Bonding, Structure, and Reactivity

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

A certain process has S_univ > 0 at 25°C. What does one know about the process?

Which relationship or statement best describes S° for the following reaction? O₃(g) + NO(g)  O₂(g) + NO₂(g)

Which relationship or statement best describes S° for the following reaction? 2H₂S(g) + 3O₂(g)  2H₂O(g) + 2SO₂(g)

For the reaction of xenon and fluorine gases to form solid XeF₄, H° = -251 kJ and G° = -121 kJ at 25°C. Calculate S° for the reaction.