Question 1

In which of the following processes do the molecules become more ordered?

Accepted Answer

A) water freezing 
B) ice melting 
C) water evaporating 
D) salt dissolving in water 
E) dry ice subliming 
A) water freezing 
B) ice melting 
C) water evaporating 
D) salt dissolving in water 
E) dry ice subliming

Question 2

Estimate ΔrG° for the following reaction at 449.0 K. CH2O(g)+ 2H2(g)→ CH4(g)+ H2O(g)ΔrH°= -94.9 kJ mol-1; ΔrS°= -224.2 J K-1 mol-1

Accepted Answer

A) +5.8 kJ mol-1 
B) +12.9 kJ mol-1 
C) -101 kJ mol-1 
D) +2.4 kJ mol-1 
E) -4.2 kJ mol-1 
A) +5.8 kJ mol-1 
B) +12.9 kJ mol-1 
C) -101 kJ mol-1 
D) +2.4 kJ mol-1 
E) -4.2 kJ mol-1

Question 3

Which of the following is true for ?rG?

Accepted Answer

A) IfF1F1F1S1?F1F1F10?rG > 0, the reaction is spontaneous in the forward direction. 
B) If Q = 1, then $\Delta$rG > ?rG. 
C) If$\Delta$rG ? 0, the reaction is spontaneous in both the reverse and forward directions. 
D) If$\Delta$rG rG = 0. 
A) IfF1F1F1S1?F1F1F10?rG > 0, the reaction is spontaneous in the forward direction. 
B) If Q = 1, then $\Delta$rG > ?rG. 
C) If$\Delta$rG ? 0, the reaction is spontaneous in both the reverse and forward directions. 
D) If$\Delta$rG rG = 0.

Question 4

Define allotrope.

Accepted Answer

An allotrope is two

Question 5

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

Accepted Answer

Spontaneity is a thermodynamic quantity

Question 6

Define entropy.

Accepted Answer

Entropy is a thermodynamic fun

Question 7

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: CaCO3(s)→ CaO(s)+ CO2(g)ΔrG° =+131.1 kJ mol-1
P(CO2)= 0.033 atm

Accepted Answer

A) -49.3 kJ mol-1 
B) -8.32 kJ mol-1 
C) +122.6 kJ mol-1 
D) +39.7 kJ mol-1 
E) +43.3 kJ mol-1 
A) -49.3 kJ mol-1 
B) -8.32 kJ mol-1 
C) +122.6 kJ mol-1 
D) +39.7 kJ mol-1 
E) +43.3 kJ mol-1

Question 8

Phosphorus and chlorine gases combine to produce phosphorus trichloride: P2(g)+ 3Cl2(g)→ 2PCl3(g)
ΔrG° at 298 K for this reaction is -642.9 kJ mol-1. The value of ΔrG at 298 K for a reaction mixture that consists of 1.5 atm P2, 1.6 atm Cl2, and 0.65 atm PCl3 is ________ kJ mol-1.

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 9

For a given reaction, ΔrH = -19.9 kJ mol-1 and ΔrS = -55.5 J K-1 mol-1. The reaction will have ΔrG = 0 at ________ K. Assume that ΔrH and ΔrS do not vary with temperature.

Accepted Answer

A) 359 
B) 2789 
C) 298 
D) 2.79 
E) 0.359 
A) 359 
B) 2789 
C) 298 
D) 2.79 
E) 0.359

Question 10

Use Hess's law to calculate ΔrG° using the following information: ClO(g)+ O3(g)→ Cl(g)+ 2O2(g)ΔrG° = ?
2O3(g)→ 3O2(g)ΔrG° = +489.6 kJ mol-1
Cl(g)+ O3(g)→ ClO(g)+ O2(g)ΔrG° = -34.5 kJ mol-1

Accepted Answer

A) -472.4 kJ mol-1 
B) -210.3 kJ mol-1 
C) +455.1 kJ mol-1 
D) +262.1 kJ mol-1 
E) +524.1 kJ mol-1 
A) -472.4 kJ mol-1 
B) -210.3 kJ mol-1 
C) +455.1 kJ mol-1 
D) +262.1 kJ mol-1 
E) +524.1 kJ mol-1

Question 11

How is a nonspontaneous process made spontaneous?

Accepted Answer

The nonspontaneous p

Question 12

Which of the following is TRUE if ln K is negative?

Accepted Answer

A) ΔrG° is positive and the reaction is spontaneous in the forward direction. 
B) ΔrG° is negative and the reaction is spontaneous in the forward direction. 
C) ΔrG° is negative and the reaction is spontaneous in the reverse direction. 
D) ΔrG° is positive and the reaction is spontaneous in the reverse direction. 
E) ΔrG° is zero and the reaction is at equilibrium. 
A) ΔrG° is positive and the reaction is spontaneous in the forward direction. 
B) ΔrG° is negative and the reaction is spontaneous in the forward direction. 
C) ΔrG° is negative and the reaction is spontaneous in the reverse direction. 
D) ΔrG° is positive and the reaction is spontaneous in the reverse direction. 
E) ΔrG° is zero and the reaction is at equilibrium.

Question 13

What is the change in Gibbs energy of a process?

Accepted Answer

A) It is a maximum amount of energy available to do work. 
B) It is energy that is lost to the surroundings. 
C) It is energy that is used to break chemical bonds. 
D) It is energy that is converted to heat. 
E) It is the total energy of a process. 
A) It is a maximum amount of energy available to do work. 
B) It is energy that is lost to the surroundings. 
C) It is energy that is used to break chemical bonds. 
D) It is energy that is converted to heat. 
E) It is the total energy of a process.

Question 14

Use the free energies of formation given below to calculate the equilibrium constant (K)for the following reaction at 298 K: 2HNO3(aq)+ NO(g)→ 3 NO2(g)+ H2O(l)K = ?
ΔfG° (kJ mol-1)-110.9 87.6 51.3 -237.1

Accepted Answer

A) 8.71 × 108 
B) 0.980 
C) 1.15 × 10-9 
D) 1.02 
E) 5.11 × 10-4 
A) 8.71 × 108 
B) 0.980 
C) 1.15 × 10-9 
D) 1.02 
E) 5.11 × 10-4

Question 15

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: 3O2(g)→ 2O3(g)ΔrG° = +326 kJ
P(O2)= 0.41 atm, P(O3)= 5.2 atm

Accepted Answer

A) +341 kJ 
B) +17.8 kJ 
C) +332 kJ 
D) -47.4 kJ 
E) -109 kJ 
A) +341 kJ 
B) +17.8 kJ 
C) +332 kJ 
D) -47.4 kJ 
E) -109 kJ

Question 16

For the following example, what is true about ΔrH and ΔrS? H2O(l)→ H2O(g)

Accepted Answer

A) a negative ΔrH and a negative ΔrS 
B) a positive ΔrH and a negative ΔrS 
C) a negative ΔrH and a positive ΔrS 
D) a positive ΔrH and a positive ΔrS 
E)  ΔrH = 0 and a positive ΔrS 
A) a negative ΔrH and a negative ΔrS 
B) a positive ΔrH and a negative ΔrS 
C) a negative ΔrH and a positive ΔrS 
D) a positive ΔrH and a positive ΔrS 
E)  ΔrH = 0 and a positive ΔrS

Question 17

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔSsurr at 355 K. Predict whether or not this reaction will be spontaneous at this temperature. 2NO(g)+ O2(g)→ 2NO2(g)ΔrH = -114 kJ

Accepted Answer

A) ΔSsurr = +114 kJ K-1 mol-1, reaction is spontaneous 
B) ΔSsurr = +114 kJ K-1 mol-1, reaction is not spontaneous 
C) ΔSsurr = +321 J K-1 mol-1, reaction is spontaneous 
D) ΔSsurr = -321 J K-1 mol-1, reaction is not spontaneous 
E) ΔSsurr = +321 J K-1 mol-1, reaction is not spontaneous 
A) ΔSsurr = +114 kJ K-1 mol-1, reaction is spontaneous 
B) ΔSsurr = +114 kJ K-1 mol-1, reaction is not spontaneous 
C) ΔSsurr = +321 J K-1 mol-1, reaction is spontaneous 
D) ΔSsurr = -321 J K-1 mol-1, reaction is not spontaneous 
E) ΔSsurr = +321 J K-1 mol-1, reaction is not spontaneous

Question 18

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔSsurr at 398 K. Predict whether or not this reaction will be spontaneous at this temperature. 4NH3(g)+ 3O2(g)→ 2N2(g)+ 6H2O(g)ΔrH = -1267 kJ

Accepted Answer

A) ΔSsurr = +12.67 kJ K-1 mol-1, reaction is not spontaneous 
B) ΔSsurr = -12.67 kJ K-1 mol-1, reaction is spontaneous 
C) ΔSsurr = +50.4 kJ K-1 mol-1, reaction is not spontaneous 
D) ΔSsurr = +3.18 kJ K-1 mol-1, reaction is spontaneous 
E) ΔSsurr = -3.18 kJ K-1 mol-1, reaction is not spontaneous 
A) ΔSsurr = +12.67 kJ K-1 mol-1, reaction is not spontaneous 
B) ΔSsurr = -12.67 kJ K-1 mol-1, reaction is spontaneous 
C) ΔSsurr = +50.4 kJ K-1 mol-1, reaction is not spontaneous 
D) ΔSsurr = +3.18 kJ K-1 mol-1, reaction is spontaneous 
E) ΔSsurr = -3.18 kJ K-1 mol-1, reaction is not spontaneous

Question 19

Calculate ΔrS° for the following reaction. The S° for each species is shown below the reaction. N2H4(l)+ H2(g)→ 2NH3(g)
S° (J K-1 mol-1)121.2 130.7 192.8

Accepted Answer

A) +133.7 J K-1 mol-1 
B) -59.1 J K-1 mol-1 
C) +118.2 J K-1 mol-1 
D) -202.3 J K-1 mol-1 
E) +178.9 J K-1 mol-1 
A) +133.7 J K-1 mol-1 
B) -59.1 J K-1 mol-1 
C) +118.2 J K-1 mol-1 
D) -202.3 J K-1 mol-1 
E) +178.9 J K-1 mol-1

Question 20

Determine ΔrG° at 298 K using the following information: FeO(s)+ CO(g)→ Fe(s)+ CO2(g)ΔrH°= -11.0 kJ mol-1; ΔrS°= -17.4 J K-1 mol-1

Accepted Answer

A) +191.0 kJ mol-1 
B) -5.8 kJ mol-1 
C) +1.6 kJ mol-1 
D) -6.4 kJ mol-1 
E) +89.5 kJ mol-1 
A) +191.0 kJ mol-1 
B) -5.8 kJ mol-1 
C) +1.6 kJ mol-1 
D) -6.4 kJ mol-1 
E) +89.5 kJ mol-1

Exam 17: Gibbs Energy and Thermodynamics

In which of the following processes do the molecules become more ordered?

Estimate ΔrG° for the following reaction at 449.0 K. CH2O(g)+ 2H2(g)→ CH4(g)+ H2O(g)ΔrH°= -94.9 kJ mol-1; ΔrS°= -224.2 J K-1 mol-1

Which of the following is true for ?rG?

Define allotrope.

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

Define entropy.

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: CaCO3(s)→ CaO(s)+ CO2(g)ΔrG° =+131.1 kJ mol-1 P(CO2)= 0.033 atm

Phosphorus and chlorine gases combine to produce phosphorus trichloride: P2(g)+ 3Cl2(g)→ 2PCl3(g) ΔrG° at 298 K for this reaction is -642.9 kJ mol-1. The value of ΔrG at 298 K for a reaction mixture that consists of 1.5 atm P2, 1.6 atm Cl2, and 0.65 atm PCl3 is ________ kJ mol-1.

For a given reaction, ΔrH = -19.9 kJ mol-1 and ΔrS = -55.5 J K-1 mol-1. The reaction will have ΔrG = 0 at ________ K. Assume that ΔrH and ΔrS do not vary with temperature.

Use Hess's law to calculate ΔrG° using the following information: ClO(g)+ O3(g)→ Cl(g)+ 2O2(g)ΔrG° = ? 2O3(g)→ 3O2(g)ΔrG° = +489.6 kJ mol-1 Cl(g)+ O3(g)→ ClO(g)+ O2(g)ΔrG° = -34.5 kJ mol-1

How is a nonspontaneous process made spontaneous?

Which of the following is TRUE if ln K is negative?

What is the change in Gibbs energy of a process?

Use the free energies of formation given below to calculate the equilibrium constant (K)for the following reaction at 298 K: 2HNO3(aq)+ NO(g)→ 3 NO2(g)+ H2O(l)K = ? ΔfG° (kJ mol-1)-110.9 87.6 51.3 -237.1

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: 3O2(g)→ 2O3(g)ΔrG° = +326 kJ P(O2)= 0.41 atm, P(O3)= 5.2 atm

For the following example, what is true about ΔrH and ΔrS? H2O(l)→ H2O(g)

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔSsurr at 355 K. Predict whether or not this reaction will be spontaneous at this temperature. 2NO(g)+ O2(g)→ 2NO2(g)ΔrH = -114 kJ

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔSsurr at 398 K. Predict whether or not this reaction will be spontaneous at this temperature. 4NH3(g)+ 3O2(g)→ 2N2(g)+ 6H2O(g)ΔrH = -1267 kJ

Calculate ΔrS° for the following reaction. The S° for each species is shown below the reaction. N2H4(l)+ H2(g)→ 2NH3(g) S° (J K-1 mol-1)121.2 130.7 192.8

Determine ΔrG° at 298 K using the following information: FeO(s)+ CO(g)→ Fe(s)+ CO2(g)ΔrH°= -11.0 kJ mol-1; ΔrS°= -17.4 J K-1 mol-1

Units of Measurement for Physical and Chemical Change

Atoms and Elements

Molecules, Compounds, and Nomenclature

Chemical Reactions and Stoichiometry

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, and Molecular Orbital Theory

Liquids, Solids, and Intermolecular Forces

Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Aqueous Ionic Equilibrium

Electrochemistry

Radioactivity and Nuclear Chemistry

Organic Chemistry I: Structures

Organic Chemistry II: Reactions

Biochemistry

Chemistry of the Nonmetals

Metals and Metallury

Transition Metals and Coordination Compounds

Filters

Estimate Δ_rG° for the following reaction at 449.0 K. CH₂O(g)+ 2H₂(g)→ CH₄(g)+ H₂O(g)Δ_rH°= -94.9 kJ mol^-1; Δ_rS°= -224.2 J K^-1 mol^-1

Which of the following is true for ?_rG?

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: CaCO₃(s)→ CaO(s)+ CO₂(g)Δ_rG° =+131.1 kJ mol^-1 P(CO₂)= 0.033 atm

For a given reaction, Δ_rH = -19.9 kJ mol^-1 and Δ_rS = -55.5 J K^-1 mol^-1. The reaction will have Δ_rG = 0 at ________ K. Assume that Δ_rH and Δ_rS do not vary with temperature.

Use Hess's law to calculate Δ_rG°using the following information: ClO(g)+ O₃(g)→ Cl(g)+ 2O₂(g)Δ_rG°= ? 2O₃(g)→ 3O₂(g)Δ_rG°= +489.6 kJ mol^-1 Cl(g)+ O₃(g)→ ClO(g)+ O₂(g)Δ_rG°= -34.5 kJ mol^-1

Use the free energies of formation given below to calculate the equilibrium constant (K)for the following reaction at 298 K: 2HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)K= ? Δ_fG° (kJ mol^-1)-110.9 87.6 51.3 -237.1

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: 3O₂(g)→ 2O₃(g)Δ_rG° = +326 kJ P(O₂)= 0.41 atm, P(O₃)= 5.2 atm

For the following example, what is true about Δ_rH and Δ_rS? H₂O(l)→ H₂O(g)

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔS_surrat 355 K. Predict whether or not this reaction will be spontaneous at this temperature. 2NO(g)+ O₂(g)→ 2NO₂(g)Δ_rH = -114 kJ

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔS_surr at 398 K. Predict whether or not this reaction will be spontaneous at this temperature. 4NH₃(g)+ 3O₂(g)→ 2N₂(g)+ 6H₂O(g)Δ_rH = -1267 kJ

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. N₂H₄(l)+ H₂(g)→ 2NH₃(g) S° (J K^-1 mol^-1)121.2 130.7 192.8

Determine Δ_rG° at 298 K using the following information: FeO(s)+ CO(g)→ Fe(s)+ CO₂(g)Δ_rH°= -11.0 kJ mol^-1; Δ_rS°= -17.4 J K^-1 mol^-1