Question 1

Which of the following processes shows a decrease in entropy of the system?

Accepted Answer

A)  2 NO(g) + O2(g) → 2 NO2(g) 
B)  COBr2(g) → CO(g) + Br2(g) 
C)  CH3OH(l) → CO(g) + 2 H2(g) 
D)  LiBrO3(s) → Li+(aq) + BrO3-(aq) 
E)  None of the above will show a decrease in entropy. 
A)  2 NO(g) + O2(g) → 2 NO2(g) 
B)  COBr2(g) → CO(g) + Br2(g) 
C)  CH3OH(l) → CO(g) + 2 H2(g) 
D)  LiBrO3(s) → Li+(aq) + BrO3-(aq) 
E)  None of the above will show a decrease in entropy.

Question 2

Identify the statement that is FALSE.

Accepted Answer

A)  The entropy of a gas is greater than the entropy of a liquid. 
B)  Entropy generally increases with increasing molecular complexity. 
C)  Free atoms have greater entropy than molecules. 
D)  Entropy increases with dissolution. 
E)  For noble gasses, entropy increases with size. 
A)  The entropy of a gas is greater than the entropy of a liquid. 
B)  Entropy generally increases with increasing molecular complexity. 
C)  Free atoms have greater entropy than molecules. 
D)  Entropy increases with dissolution. 
E)  For noble gasses, entropy increases with size.

Question 3

Which one of the following would be expected to have the lowest standard molar entropy,S°,at 25°C?

Accepted Answer

A)  C8H18(s) 
B)  C8H18(l) 
C)  C14H30(g) 
D)  C14H30OH(l) 
A)  C8H18(s) 
B)  C8H18(l) 
C)  C14H30(g) 
D)  C14H30OH(l)

Question 4

Identify the compound with the most negative standard free energy of formation.

Accepted Answer

A)  NaF(s) 
B)  N2(g) 
C)  NO(g) 
D)  O3(g) 
E)  It is hard to determine. 
A)  NaF(s) 
B)  N2(g) 
C)  NO(g) 
D)  O3(g) 
E)  It is hard to determine.

Question 5

For a given reaction,ΔH = +35.5 kJ/mol and ΔS = +83.6 J/Kmol.The reaction is spontaneous ________.Assume that ΔH and ΔS do not vary with temperature.

Accepted Answer

A) at T 425 K C) at all temperatures D) at T > 298 K E) at T < 298 K A) at T 425 K C) at all temperatures D) at T > 298 K E) at T < 298 K

Question 6

Identify the compound that is an allotrope of carbon.

Accepted Answer

A)  methanol 
B)  graphite 
C)  baking soda 
D)  gasoline 
E)  sugar 
A)  methanol 
B)  graphite 
C)  baking soda 
D)  gasoline 
E)  sugar

Question 7

Consider the following reaction at constant P.Use the information here to determine the value of ΔSsurr at 298 K.Predict whether or not this reaction will be spontaneous at this temperature. N2(g)+ 2 O2(g)→ 2 NO2(g)ΔH = +66.4 kJ

Accepted Answer

A)  ΔSsurr = +223 J/K, reaction is spontaneous 
B)  ΔSsurr = -223 J/K, reaction is not spontaneous 
C)  ΔSsurr = -66.4 J/K, reaction is not spontaneous 
D)  ΔSsurr = +2656 kJ/K, reaction is not spontaneous 
E)  ΔSsurr = -66.4 J/K, it is not possible to predict the spontaneity of this reaction without more information. 
A)  ΔSsurr = +223 J/K, reaction is spontaneous 
B)  ΔSsurr = -223 J/K, reaction is not spontaneous 
C)  ΔSsurr = -66.4 J/K, reaction is not spontaneous 
D)  ΔSsurr = +2656 kJ/K, reaction is not spontaneous 
E)  ΔSsurr = -66.4 J/K, it is not possible to predict the spontaneity of this reaction without more information.

Question 8

Match between columns Premises: Q > K Q < K Q < 1 Q > 1 Q = K Q = 1

Accepted Answer

The Answer of equilibrium and ΔG < ΔG° and DG is...

Question 9

Given the following equation, C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g)ΔG°rxn = -2074 kJ
Calculate ΔG°rxn for the following reaction.
7 C3H8(g)+ 35 O2(g)→ 21 CO2(g)+ 28 H2O(g)

Accepted Answer

A)  -2074 kJ 
B)  +14518 kJ 
C)  -14518 kJ 
D)  +2074 kJ 
E)  -296 kJ 
A)  -2074 kJ 
B)  +14518 kJ 
C)  -14518 kJ 
D)  +2074 kJ 
E)  -296 kJ

Question 10

Match between columns Premises: Q = K Q = 1 Q > 1 Q < K Q < 1 Q > K

Accepted Answer

The Answer of ΔG > ΔG° and DG < 0 is...

Question 11

Estimate ΔG°rxn for the following reaction at 825 K. 2 Hg(g)+ O2(g)→ 2 HgO(s)ΔH°= -304.2 kJ; ΔS°= -414.2 J/K

Accepted Answer

A)  -2.63 kJ 
B)  -37 kJ 
C)  +37 kJ 
D)  +645 kJ 
E)  -645 kJ 
A)  -2.63 kJ 
B)  -37 kJ 
C)  +37 kJ 
D)  +645 kJ 
E)  -645 kJ

Question 12

Phosphorous and chlorine gases combine to produce phosphorous trichloride: P2(g)+ 3 Cl2(g)→ 2 PCl3(g)
ΔG° at 298 K for this reaction is -642.9 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P2,1.6 atm Cl2,and 0.65 atm PCl3 is ________.

Accepted Answer

A)  -44.2 
B)  -3.88 × 103 
C)  -7.28 × 103 
D)  -708.4 
E)  -649.5 
A)  -44.2 
B)  -3.88 × 103 
C)  -7.28 × 103 
D)  -708.4 
E)  -649.5

Question 13

Give the name of the reaction that does not achieve the theoretical limits with respect to free energy in thermodynamics.

Accepted Answer

A)  reversible reaction 
B)  forward reaction 
C)  reverse reaction 
D)  equilibrium reaction 
E)  irreversible reaction 
A)  reversible reaction 
B)  forward reaction 
C)  reverse reaction 
D)  equilibrium reaction 
E)  irreversible reaction

Question 14

Which of the following processes has a ΔS < 0?

Accepted Answer

A)  ethanol freezes 
B)  isopropyl alcohol condenses 
C)  2-propanol (g, at 555 K) → 2-propanol (g, at 400 K) 
D)  carbon dioxide(g) → carbon dioxide(s) 
E)  All of the above processes have a ΔS < 0. 
A)  ethanol freezes 
B)  isopropyl alcohol condenses 
C)  2-propanol (g, at 555 K) → 2-propanol (g, at 400 K) 
D)  carbon dioxide(g) → carbon dioxide(s) 
E)  All of the above processes have a ΔS < 0.

Question 15

For the following example,identify the following. 2 H2(g)+ O2(g)→ 2 H2O(g)

Accepted Answer

A)  a negative ΔH and a negative ΔS 
B)  a positive ΔH and a negative ΔS 
C)  a negative ΔH and a positive ΔS 
D)  a positive ΔH and a positive ΔS 
E)  It is not possible to determine without more information. 
A)  a negative ΔH and a negative ΔS 
B)  a positive ΔH and a negative ΔS 
C)  a negative ΔH and a positive ΔS 
D)  a positive ΔH and a positive ΔS 
E)  It is not possible to determine without more information.

Question 16

Which one of the following has the highest standard molar entropy,S°,at 25°C?

Accepted Answer

A)  NaCl(s) 
B)  NaBr(s) 
C)  NaI(s) 
D)  NaF(s) 
E)  They have the same value. 
A)  NaCl(s) 
B)  NaBr(s) 
C)  NaI(s) 
D)  NaF(s) 
E)  They have the same value.

Question 17

Why can't we say that a spontaneous reaction is a fast reaction?

Accepted Answer

Spontaneity is a thermodynamic

Question 18

Place the following in order of increasing molar entropy at 298 K. NO CO SO

Accepted Answer

A)  NO < CO < SO 
B)  SO < CO < NO 
C)  SO < NO < CO 
D)  CO < SO < NO 
E)  CO < NO < SO 
A)  NO < CO < SO 
B)  SO < CO < NO 
C)  SO < NO < CO 
D)  CO < SO < NO 
E)  CO < NO < SO

Question 19

Choose the statement below that is TRUE.

Accepted Answer

A)  K > 1, ΔG°rxn is positive. 
B)  K rxn is negative. 
C)  ΔG°rxn = 0 at equilibrium. 
D)  ΔGrxn = 0 at equilibrium. 
E)  None of the above statements are true. 
A)  K > 1, ΔG°rxn is positive. 
B)  K rxn is negative. 
C)  ΔG°rxn = 0 at equilibrium. 
D)  ΔGrxn = 0 at equilibrium. 
E)  None of the above statements are true.

Question 20

Consider a reaction that has a negative ΔH and a negative ΔS.Which of the following statements is TRUE?

Accepted Answer

A)  This reaction will be spontaneous only at low temperatures. 
B)  This reaction will be spontaneous at all temperatures. 
C)  This reaction will be nonspontaneous at all temperatures. 
D)  This reaction will be nonspontaneous only at low temperatures. 
E)  It is not possible to determine without more information. 
A)  This reaction will be spontaneous only at low temperatures. 
B)  This reaction will be spontaneous at all temperatures. 
C)  This reaction will be nonspontaneous at all temperatures. 
D)  This reaction will be nonspontaneous only at low temperatures. 
E)  It is not possible to determine without more information.

Exam 18: Free Energy and Thermodynamics

Which of the following processes shows a decrease in entropy of the system?

Identify the statement that is FALSE.

Which one of the following would be expected to have the lowest standard molar entropy,S°,at 25°C?

Identify the compound with the most negative standard free energy of formation.

For a given reaction,ΔH = +35.5 kJ/mol and ΔS = +83.6 J/Kmol.The reaction is spontaneous ________.Assume that ΔH and ΔS do not vary with temperature.

Identify the compound that is an allotrope of carbon.

Consider the following reaction at constant P.Use the information here to determine the value of ΔSsurr at 298 K.Predict whether or not this reaction will be spontaneous at this temperature. N2(g)+ 2 O2(g)→ 2 NO2(g)ΔH = +66.4 kJ

Given the following equation, C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g)ΔG°rxn = -2074 kJ Calculate ΔG°rxn for the following reaction. 7 C3H8(g)+ 35 O2(g)→ 21 CO2(g)+ 28 H2O(g)

Estimate ΔG°rxn for the following reaction at 825 K. 2 Hg(g)+ O2(g)→ 2 HgO(s)ΔH°= -304.2 kJ; ΔS°= -414.2 J/K

Phosphorous and chlorine gases combine to produce phosphorous trichloride: P2(g)+ 3 Cl2(g)→ 2 PCl3(g) ΔG° at 298 K for this reaction is -642.9 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P2,1.6 atm Cl2,and 0.65 atm PCl3 is ________.

Give the name of the reaction that does not achieve the theoretical limits with respect to free energy in thermodynamics.

Which of the following processes has a ΔS < 0?

For the following example,identify the following. 2 H2(g)+ O2(g)→ 2 H2O(g)

Which one of the following has the highest standard molar entropy,S°,at 25°C?

Why can't we say that a spontaneous reaction is a fast reaction?

Place the following in order of increasing molar entropy at 298 K. NO CO SO

Choose the statement below that is TRUE.

Consider a reaction that has a negative ΔH and a negative ΔS.Which of the following statements is TRUE?

Matter, measurement, and Problem Solving

Atoms and Elements

Molecules,compounds,and Chemical Equations

Chemical Quantities and Aqueous Reactions

Gases

Thermochemistry

The Quantum-Mechanical Model of the Atom

Periodic Properties of the Elements

Chemical Bonding I: Lewis Theory

Chemical Bonding Ii: Molecular Shapes,valence Bond Theory,

Liquids,solids,and Intermolecular Forces

Solids and Modern Materials

Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Aqueous Ionic Equilibrium

Electrochemistry

Radioactivity and Nuclear Chemistry

Organic Chemistry

Biochemistry

Chemistry of the Nonmetals

Metals and Metallurgy

Transition Metals and Coordination Compounds

Filters

Consider the following reaction at constant P.Use the information here to determine the value of ΔS_surrat 298 K.Predict whether or not this reaction will be spontaneous at this temperature. N₂(g)+ 2 O₂(g)→ 2 NO₂(g)ΔH = +66.4 kJ

Given the following equation, C₃H₈(g)+ 5 O₂(g)→ 3 CO₂(g)+ 4 H₂O(g)ΔG°_rxn = -2074 kJ Calculate ΔG°_rxn for the following reaction. 7 C₃H₈(g)+ 35 O₂(g)→ 21 CO₂(g)+ 28 H₂O(g)

Estimate ΔG°_rxn for the following reaction at 825 K. 2 Hg(g)+ O₂(g)→ 2 HgO(s)ΔH°= -304.2 kJ; ΔS°= -414.2 J/K

Phosphorous and chlorine gases combine to produce phosphorous trichloride: P₂(g)+ 3 Cl₂(g)→ 2 PCl₃(g) ΔG° at 298 K for this reaction is -642.9 kJ/mol.The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P₂,1.6 atm Cl₂,and 0.65 atm PCl₃ is ________.

For the following example,identify the following. 2 H₂(g)+ O₂(g)→ 2 H₂O(g)