Question 1

In living systems, thermodynamically favorable reactions provide the free energy needed to drive necessary but thermodynamically unfavorable reactions.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following will decrease the entropy of an inert gas system?

Accepted Answer

A)   Increasing the temperature
B)   Decreasing the volume
C)   Adding a different inert gas to the system
D)   Increasing the molar mass
E)   Decreasing the pressure

Question 3

As a chemical reaction proceeds toward equilibrium, the free energy of the system decreases at constant temperature and constant pressure.

Accepted Answer

A) True 
 B)False

Question 4

What is defined as the measure of accessible energy levels of a substance at 1 atm?

Accepted Answer

A)   Atmospheric disorder
B)   Atmospheric pressure
C)   Atmospheric entropy
D)   Specific pressure
E)   Standard entropy

Question 5

Sulfuryl dichloride may be formed from the reaction of sulfur dioxide and chlorine. SO2(g)  + Cl2(g)  → SO2Cl2(g)  2(g)  + Cl2(g)  → SO2Cl2(g)    What is ΔG°rxn for this reaction at 600 K? A)  -162.8 kJ/mol B)  -40.1 kJ/mol C)  -28.4 kJ/mol D)  28.4 kJ/mol E)  162.8 kJ/mol" class="answers-bank-image d-inline" rel="preload" > What is ΔG°rxn for this reaction at 600 K?

Accepted Answer

A)   -162.8 kJ/mol
B)   -40.1 kJ/mol
C)   -28.4 kJ/mol
D)   28.4 kJ/mol
E)   162.8 kJ/mol

Question 6

The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury(II)  oxide: HgO(s)  → Hg(l)  + ½O2(g) , ΔH° = 90.84 kJ/mol. Estimate the temperature at which this reaction will become spontaneous under standard state conditions. 2(g) , ΔH° = 90.84 kJ/mol. Estimate the temperature at which this reaction will become spontaneous under standard state conditions.   A)  108 K B)  430. K C)  620. K D)  775 K E)  840. K" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   108 K
B)   430. K
C)   620. K
D)   775 K
E)   840. K

Question 7

Hydrogen sulfide decomposes according to the following reaction: 2H2S(g)  → 2H2(g)  + S2(g) 
For this reaction at 298 K, ΔS°rxn = 78.1 J/K • mol, ΔH°rxn = 169.4 kJ/mol, and ΔG°rxn = 146.1 kJ/mol. What is ΔG°rxn at 900. K?

Accepted Answer

A)   -69881 kJ/mol
B)   48.4 kJ/mol
C)   99.1 kJ/mol
D)   240 kJ/mol
E)   441 kJ/mol

Question 8

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

Accepted Answer

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

Question 9

Which statement is correct?

Accepted Answer

A)   Heating always decreases the entropy of a system.
B)   The reaction that results in an increase in the number of moles of gas always decreases the entropy of a system.
C)   The greater number of particles leads to a smaller number of microstates.
D)   An increase in the temperature decreases all types of molecular motions.
E)   The solvation process usually leads to an increase in entropy.

Question 10

For the reaction of xenon and fluorine gases to form solid XeF4, ΔH° = -251 kJ/mol
and ΔG° = -121 kJ/mol at 25°C. Calculate ΔS° for the reaction.

Accepted Answer

Question 11

According to which scientific law does the entropy of the universe increase in spontaneous processes and remain unchanged in equilibrium processes?

Accepted Answer

A)   1st law of thermodynamics
B)   1st law of entropy
C)   1st universal law
D)   2nd law of thermodynamics
E)   3rd law of thermodynamics

Question 12

Calculate ΔG° for the combustion of ethanol vapor, C2H5OH(g) , at 750.°C in oxygen to form carbon dioxide and water vapor. The following data are valid at 25°C: 2H5OH(g) , at 750.°C in oxygen to form carbon dioxide and water vapor. The following data are valid at 25°C:   A)  -1407 kJ/mol B)  -2151 kJ/mol C)  -1307 kJ/mol D)  -4486 kJ/mol E)  -1377 kJ/mol" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   -1407 kJ/mol
B)   -2151 kJ/mol
C)   -1307 kJ/mol
D)   -4486 kJ/mol
E)   -1377 kJ/mol

Question 13

Which of the following substances has the greatest entropy per mole?

Accepted Answer

A)   O2(g) 
B)   N2(g) 
C)   CO(g) 
D)   CO2(g) 
E)   C4H10(g)

Question 14

a. Explain what is meant by a spontaneous process.
b. Is a spontaneous process necessarily a rapid one? Explain, and provide a real reaction as an example to illustrate your answer.

Accepted Answer

a. A spontaneous process is one which wi...

Question 15

What is ΔG°rxn for the combustion of propane? C3H8(g)  + 5O2(g)  → 3CO2(g)  + 4H2O(g)  rxn for the combustion of propane? C3H8(g)  + 5O2(g)  → 3CO2(g)  + 4H2O(g)    A)  -2073.1 kJ/mol B)  -1387.3 kJ/mol C)  -598.5 kJ/mol D)  +598.5 kJ/mol E)  +2073.1 kJ/mol" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   -2073.1 kJ/mol
B)   -1387.3 kJ/mol
C)   -598.5 kJ/mol
D)   +598.5 kJ/mol
E)   +2073.1 kJ/mol

Question 16

Which is true for a system at equilibrium?

Accepted Answer

A)   ΔS°sys = ΔS°surr
B)   ΔS°sys = -ΔS°surr
C)   ΔS°sys = ΔS°surr = 0
D)   ΔS°univ > 0
E)   ΔS°univ < 0

Question 17

Which species will have the greatest absolute entropy at 25°C?

Accepted Answer

A)   Ne(g) 
B)   C2H2(g) 
C)   H2O(l) 
D)   C2H5OH(l) 
E)   C4H10(g)

Question 18

What is ΔS° for the following reaction? SiCl4(g)  + 2Mg(s)  → 2MgCl2(s)  + Si(s)  4(g)  + 2Mg(s)  → 2MgCl2(s)  + Si(s)    A)  -254.96 J/K • mol B)  -198.02 J/K • mol C)  +198.02 J/K • mol D)  +254.96 J/K • mol E)  +471.86 J/K • mol" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   -254.96 J/K • mol
B)   -198.02 J/K • mol
C)   +198.02 J/K • mol
D)   +254.96 J/K • mol
E)   +471.86 J/K • mol

Question 19

Which statement is correct?

Accepted Answer

A)   Oxygen is formed during the metabolism of food.
B)   The metabolism process results in a positive ΔGo.
C)   ADP is hydrolyzed to ATP and phosphoric acid in the body.
D)   A protein is a polymer made of carbohydrate units.
E)   ATP functions to store energy until it is needed by the body.

Question 20

Which, if any, of the following processes is spontaneous under the specified conditions?

Accepted Answer

A)   H2O(l)  → H2O(s)  at 25°C, 1 atm pressure
B)   CO2(s)  → CO2(g)  at 0°C, 1 atm pressure
C)   2H2O(g)  → 2H2(g)  + O2(g)  at 25°C, 1 atm pressure
D)   C(graphite)  → C(diamond)  at 25°C, 1 atm pressure
E)   None of these processes is spontaneous.

Exam 18: Entropy, Free Energy, and Equilibrium

For the reaction of xenon and fluorine gases to form solid XeF4, ΔH° = -251 kJ/mol and ΔG° = -121 kJ/mol at 25°C. Calculate ΔS° for the reaction.

Correct AnswerverifiedShow Answer

Hydrogen sulfide decomposes according to the following reaction: 2H2S(g) → 2H2(g) + S2(g) For this reaction at 298 K, ΔS°rxn = 78.1 J/K • mol, ΔH°rxn = 169.4 kJ/mol, and ΔG°rxn = 146.1 kJ/mol. What is ΔG°rxn at 900. K?

Correct AnswerverifiedShow Answer

a. Explain what is meant by a spontaneous process. b. Is a spontaneous process necessarily a rapid one? Explain, and provide a real reaction as an example to illustrate your answer.

Correct Answerverifieda. A spontaneous process is one which wi...View AnswerShow Answer

The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury(II) oxide: HgO(s) → Hg(l) + ½O2(g) , ΔH° = 90.84 kJ/mol. Estimate the temperature at which this reaction will become spontaneous under standard state conditions.

Correct AnswerverifiedShow Answer

Which, if any, of the following processes is spontaneous under the specified conditions?

Correct AnswerverifiedShow Answer

As a chemical reaction proceeds toward equilibrium, the free energy of the system decreases at constant temperature and constant pressure.

Correct AnswerverifiedShow Answer

In living systems, thermodynamically favorable reactions provide the free energy needed to drive necessary but thermodynamically unfavorable reactions.

Correct AnswerverifiedShow Answer

What is defined as the measure of accessible energy levels of a substance at 1 atm?

Correct AnswerverifiedShow Answer

Which statement is correct?

Correct AnswerverifiedShow Answer

Sulfuryl dichloride may be formed from the reaction of sulfur dioxide and chlorine. SO2(g) + Cl2(g) → SO2Cl2(g) What is ΔG°rxn for this reaction at 600 K?

Correct AnswerverifiedShow Answer

Which of the following substances has the greatest entropy per mole?

Correct AnswerverifiedShow Answer

Which of the following will decrease the entropy of an inert gas system?

Correct AnswerverifiedShow Answer

Calculate ΔG° for the combustion of ethanol vapor, C2H5OH(g) , at 750.°C in oxygen to form carbon dioxide and water vapor. The following data are valid at 25°C:

Correct AnswerverifiedShow Answer

Which is true for a system at equilibrium?

Correct AnswerverifiedShow Answer

Which statement is correct?

Correct AnswerverifiedShow Answer

Which species will have the greatest absolute entropy at 25°C?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What is ΔS° for the following reaction? SiCl4(g) + 2Mg(s) → 2MgCl2(s) + Si(s)

Correct AnswerverifiedShow Answer

What is ΔG°rxn for the combustion of propane? C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)

Correct AnswerverifiedShow Answer

According to which scientific law does the entropy of the universe increase in spontaneous processes and remain unchanged in equilibrium processes?

Correct AnswerverifiedShow Answer

For the reaction of xenon and fluorine gases to form solid XeF₄, ΔH° = -251 kJ/mol and ΔG° = -121 kJ/mol at 25°C. Calculate ΔS° for the reaction.

Correct Answer
verified

Hydrogen sulfide decomposes according to the following reaction: 2H₂S(g) → 2H₂(g) + S₂(g) For this reaction at 298 K, ΔS°_rxn = 78.1 J/K • mol, ΔH°_rxn = 169.4 kJ/mol, and ΔG°_rxn = 146.1 kJ/mol. What is ΔG°_rxn at 900. K?

Correct Answer
verified

Correct Answer
verified
a. A spontaneous process is one which wi...
View Answer

The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury(II) oxide: HgO(s) → Hg(l) + ½O₂(g) , ΔH° = 90.84 kJ/mol. Estimate the temperature at which this reaction will become spontaneous under standard state conditions.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Sulfuryl dichloride may be formed from the reaction of sulfur dioxide and chlorine. SO₂(g) + Cl₂(g) → SO₂Cl₂(g) What is ΔG°_rxn for this reaction at 600 K?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Calculate ΔG° for the combustion of ethanol vapor, C₂H₅OH(g) , at 750.°C in oxygen to form carbon dioxide and water vapor. The following data are valid at 25°C:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What is ΔS° for the following reaction? SiCl₄(g) + 2Mg(s) → 2MgCl₂(s) + Si(s)

Correct Answer
verified

What is ΔG°_rxn for the combustion of propane? C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(g)

Correct Answer
verified

Correct Answer
verified