Question 1

For a chemical reaction to be spontaneous at all temperatures,which of the following conditions must be met?

Accepted Answer

A) ($\Delta$S° > 0,$\Delta$H° > 0) 
B) ($\Delta$S° > 0,$\Delta$H°  0) 
E) (It is not possible for a reaction to be spontaneous at all temperatures. 
A) ($\Delta$S° > 0,$\Delta$H° > 0) 
B) ($\Delta$S° > 0,$\Delta$H°  0) 
E) (It is not possible for a reaction to be spontaneous at all temperatures.

Question 2

Calculate $\Delta$S° for the reaction
2Cl2(g)+ SO2(g) $\to$SOCl2(g)+ Cl2O(g)

Accepted Answer

A) -118.2 J/K 
B) -104.8 J/K 
C) 104.8 J/K 
D) 118.2 J/K 
E) 1270.0 J/K 
A) -118.2 J/K 
B) -104.8 J/K 
C) 104.8 J/K 
D) 118.2 J/K 
E) 1270.0 J/K

Question 3

Iron(III)oxide can be reduced by carbon monoxide.
Fe2O3(s)+ 3CO(g)  
2Fe(s)+ 3CO2(g)
Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Accepted Answer

A) 7.0 $\times$ 10-6 
B) 1.3 $\times$ 10-3 
C) 2.2 $\times$ 104 
D) 1.4 $\times$ 105 
E)  > 2.0 $\times$ 105 
A) 7.0 $\times$ 10-6 
B) 1.3 $\times$ 10-3 
C) 2.2 $\times$ 104 
D) 1.4 $\times$ 105 
E)  > 2.0 $\times$ 105

Question 4

For each of the following pairs,predict which (A or B)will have the greater entropy,and in one sentence indicate your reasoning.

Accepted Answer

a.A has greater entropy.HI and HBr are c

Question 5

Which relationship best describes $\Delta$S° for the following reaction?
CO(g)+ H2O(g) $\to$ CO2(g)+ H2(g)

Accepted Answer

A) ($\Delta$S° = $\Delta$H°) B) (F$\Delta$S° = $\Delta$H°/T) C) ($\Delta$S° > 0) D) ($\Delta$S° < 0) E) ($\Delta$S° $\approx$ 0) A) ($\Delta$S° = $\Delta$H°) B) (F$\Delta$S° = $\Delta$H°/T) C) ($\Delta$S° > 0) D) ($\Delta$S° < 0) E) ($\Delta$S° $\approx$ 0)

Question 6

You are given pure samples of pentane,CH3CH2CH2CH2CH3(l),and 1,3-pentadiene,CH2=CHCH=CHCH3(l).What prediction would you make concerning the standard molar entropies of pentane,S°(pentane)and 1,3-pentadiene,S°(1,3-pentadiene),at 298 K?

Accepted Answer

A) S°(pentane)> S°(1,3-pentadiene) 
B) S°(pentane)2) 
E) More information is needed to make reasonable predictions. 
A) S°(pentane)> S°(1,3-pentadiene) 
B) S°(pentane)2) 
E) More information is needed to make reasonable predictions.

Question 7

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 8

The reaction of methane with water to form carbon dioxide and hydrogen is non-spontaneous at 298 K.At what temperature will this system make the transition from non-spontaneous to spontaneous? The data refer to 298 K.
CH4(g)+ 2H2O(g)  
CO2(g)+ 4H2(g)

Accepted Answer

A) 658 K 
B) 683 K 
C) 955 K 
D) 1047 K 
E) 1229 K 
A) 658 K 
B) 683 K 
C) 955 K 
D) 1047 K 
E) 1229 K

Question 9

Under a given set of conditions,all microstates of a system are equally probable.

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

A) qsys > 0,$\Delta$Ssurr sys surr > 0 C) qsys surr sys > 0,$\Delta$Ssurr > 0 E) w < 0 A) qsys > 0,$\Delta$Ssurr sys surr > 0 C) qsys surr sys > 0,$\Delta$Ssurr > 0 E) w < 0

Question 11

The formation constant for the reaction
Ag+(aq)+ 2NH3(aq)  
Ag(NH3)2+(aq)
Is Kf = 1.7 $\times$ 107 at 25°C.What is $\Delta$G° at this temperature?

Accepted Answer

A) -1.5 kJ 
B) -3.5 kJ 
C) -18 kJ 
D) -23 kJ 
E) -41 kJ 
A) -1.5 kJ 
B) -3.5 kJ 
C) -18 kJ 
D) -23 kJ 
E) -41 kJ

Question 12

Elemental boron can be formed by reaction of boron trichloride with hydrogen.
BCl3(g)+ 1.5H2(g) $\to$ B(s)+ 3HCl(g)
 
If $\Delta$S° = 80.3 J/K,what is S° for BCl3(g)?

Accepted Answer

A) -18.2 J/K·mol 
B) 18.2 J/K·mol 
C) 290.1 J/K·mol 
D) 355.4 J/K·mol 
E) 450.6 J/K·mol 
A) -18.2 J/K·mol 
B) 18.2 J/K·mol 
C) 290.1 J/K·mol 
D) 355.4 J/K·mol 
E) 450.6 J/K·mol

Question 13

The complete combustion of liquid benzene is represented by the equation:
C6H6(l)+ 7   
O2(g) $\to$ 6CO2(g)+ 3H2O(l)
Using the data below,calculate,for this reaction
a.$\Delta$H°
b.$\Delta$S°
c.$\Delta$G° at 25°C.

Accepted Answer

a.@#LAT-DLM&H° = -32

Question 14

In the expression,S = k ln W,W is called the number of microstates.Explain clearly the meaning of the word "microstate",and why a system under a given set of conditions normally has many microstates.

Accepted Answer

A microstate is a specific,quantized sta

Question 15

A chemical reaction has $\Delta$G° = 10.0 kJ and $\Delta$S° = 50.0 J/K
a.Calculate $\Delta$H° for this reaction at 25°C.
b.Could this reaction ever be spontaneous? Explain your answer.

Accepted Answer

a.@#LAT-DLM&H° = 24.9 kJ
b.Yes.Assuming

Question 16

What is the free energy change,S1U1P1$\circ$S1S1P0G°,for the equilibrium between hydrogen iodide,hydrogen,and iodine at 453°C? Kc = 0.020
2HI(g)  
H2(g)+ I2(g)

Accepted Answer

A) 6.4 kJ 
B) 8.8 kJ 
C) 15 kJ 
D) 19 kJ 
E) 24 kJ 
A) 6.4 kJ 
B) 8.8 kJ 
C) 15 kJ 
D) 19 kJ 
E) 24 kJ

Question 17

Given: C2H2(g)$\to$ 2C(graphite)+ H2(g)$\Delta$G° = -209 kJ
A sample of gaseous C2H2 (acetylene,or ethyne)was stored for one year,yet at the end of this period the sample remained unchanged and no graphite or hydrogen gas had been formed.Briefly explain why there is no inconsistency between the sign of $\Delta$G° and the apparent stability of the sample.

Accepted Answer

Relative to graphite and hydrogen,acetyl

Question 18

Which relationship or statement best describes $\Delta$S° for the following reaction?
C2H5OH(l)+ 3O2(g) $\to$ 2CO2(g)+ 3H2O(l)

Accepted Answer

A) ($\Delta$S° $\approx$ 0) 
B) ($\Delta$S°  0) 
D) ($\Delta$S° = $\Delta$H°/T) 
E) More information is needed to make a reasonable prediction. 
A) ($\Delta$S° $\approx$ 0) 
B) ($\Delta$S°  0) 
D) ($\Delta$S° = $\Delta$H°/T) 
E) More information is needed to make a reasonable prediction.

Question 19

Which relationship or statement best describes $\Delta$S° for the following reaction?
2NH3(g)+ 2ClF3(g) $\to$ 6HF(g)+ N2(g)+ Cl2(g)

Accepted Answer

A) ($\Delta$S° $\approx$ 0) 
B) ($\Delta$S°  0) 
D) ($\Delta$S° = $\Delta$H°/T) 
E) More information is needed to make a reasonable prediction. 
A) ($\Delta$S° $\approx$ 0) 
B) ($\Delta$S°  0) 
D) ($\Delta$S° = $\Delta$H°/T) 
E) More information is needed to make a reasonable prediction.

Question 20

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

For a chemical reaction to be spontaneous at all temperatures,which of the following conditions must be met?

Calculate $\Delta$ S° for the reaction 2Cl₂(g)+ SO₂(g) $\to$ SOCl₂(g)+ Cl₂O(g) $Calculate \Delta S° for the reaction 2Cl<sub>2</sub>(g)+ SO<sub>2</sub>(g) \to SOCl<sub>2</sub>(g)+ Cl<sub>2</sub>O(g)$

Iron(III)oxide can be reduced by carbon monoxide. Fe₂O₃(s)+ 3CO(g) 2Fe(s)+ 3CO₂(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

For each of the following pairs,predict which (A or B)will have the greater entropy,and in one sentence indicate your reasoning.

Which relationship best describes $\Delta$ S° for the following reaction? CO(g)+ H₂O(g) $\to$ CO₂(g)+ H₂(g)

You are given pure samples of pentane,CH₃CH₂CH₂CH₂CH₃(l),and 1,3-pentadiene,CH₂=CHCH=CHCH₃(l).What prediction would you make concerning the standard molar entropies of pentane,S°(pentane)and 1,3-pentadiene,S°(1,3-pentadiene),at 298 K?

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

The reaction of methane with water to form carbon dioxide and hydrogen is non-spontaneous at 298 K.At what temperature will this system make the transition from non-spontaneous to spontaneous? The data refer to 298 K. CH₄(g)+ 2H₂O(g) CO₂(g)+ 4H₂(g)

Under a given set of conditions,all microstates of a system are equally probable.

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

In the expression,S = k ln W,W is called the number of microstates.Explain clearly the meaning of the word "microstate",and why a system under a given set of conditions normally has many microstates.

A chemical reaction has $\Delta$ G° = 10.0 kJ and $\Delta$ S° = 50.0 J/K a.Calculate $\Delta$ H° for this reaction at 25°C. b.Could this reaction ever be spontaneous? Explain your answer.

Which relationship or statement best describes $\Delta$ S° for the following reaction? C₂H₅OH(l)+ 3O₂(g) $\to$ 2CO₂(g)+ 3H₂O(l)

Which relationship or statement best describes $\Delta$ S° for the following reaction? 2NH₃(g)+ 2ClF₃(g) $\to$ 6HF(g)+ N₂(g)+ Cl₂(g)

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.

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three 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 Solutions

The Main-Group Elements: Applying Principles of Bonding and Structure

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 Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

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

For a chemical reaction to be spontaneous at all temperatures,which of the following conditions must be met?

Calculate Δ\DeltaΔ S° for the reaction 2Cl2(g)+ SO2(g) →\to→ SOCl2(g)+ Cl2O(g)

Iron(III)oxide can be reduced by carbon monoxide. Fe2O3(s)+ 3CO(g) 2Fe(s)+ 3CO2(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

For each of the following pairs,predict which (A or B)will have the greater entropy,and in one sentence indicate your reasoning.

Which relationship best describes Δ\DeltaΔ S° for the following reaction? CO(g)+ H2O(g) →\to→ CO2(g)+ H2(g)

You are given pure samples of pentane,CH3CH2CH2CH2CH3(l),and 1,3-pentadiene,CH2=CHCH=CHCH3(l).What prediction would you make concerning the standard molar entropies of pentane,S°(pentane)and 1,3-pentadiene,S°(1,3-pentadiene),at 298 K?

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

The reaction of methane with water to form carbon dioxide and hydrogen is non-spontaneous at 298 K.At what temperature will this system make the transition from non-spontaneous to spontaneous? The data refer to 298 K. CH4(g)+ 2H2O(g) CO2(g)+ 4H2(g)

Under a given set of conditions,all microstates of a system are equally probable.

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

The formation constant for the reaction Ag+(aq)+ 2NH3(aq) Ag(NH3)2+(aq) Is Kf = 1.7 ×\times× 107 at 25°C.What is Δ\DeltaΔ G° at this temperature?

Elemental boron can be formed by reaction of boron trichloride with hydrogen. BCl3(g)+ 1.5H2(g) →\to→ B(s)+ 3HCl(g) If Δ\DeltaΔ S° = 80.3 J/K,what is S° for BCl3(g)?

The complete combustion of liquid benzene is represented by the equation: C6H6(l)+ 7 O2(g) →\to→ 6CO2(g)+ 3H2O(l) Using the data below,calculate,for this reaction a. Δ\DeltaΔ H° b. Δ\DeltaΔ S° c. Δ\DeltaΔ G° at 25°C.

In the expression,S = k ln W,W is called the number of microstates.Explain clearly the meaning of the word "microstate",and why a system under a given set of conditions normally has many microstates.

A chemical reaction has Δ\DeltaΔ G° = 10.0 kJ and Δ\DeltaΔ S° = 50.0 J/K a.Calculate Δ\DeltaΔ H° for this reaction at 25°C. b.Could this reaction ever be spontaneous? Explain your answer.

What is the free energy change, ∘\circ∘ G°,for the equilibrium between hydrogen iodide,hydrogen,and iodine at 453°C? Kc = 0.020 2HI(g) H2(g)+ I2(g)

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? C2H5OH(l)+ 3O2(g) →\to→ 2CO2(g)+ 3H2O(l)

Which relationship or statement best describes Δ\DeltaΔ S° for the following reaction? 2NH3(g)+ 2ClF3(g) →\to→ 6HF(g)+ N2(g)+ Cl2(g)

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.

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three 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 Solutions

The Main-Group Elements: Applying Principles of Bonding and Structure

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 Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Calculate $\Delta$ S° for the reaction 2Cl₂(g)+ SO₂(g) $\to$ SOCl₂(g)+ Cl₂O(g) $Calculate \Delta S° for the reaction 2Cl<sub>2</sub>(g)+ SO<sub>2</sub>(g) \to SOCl<sub>2</sub>(g)+ Cl<sub>2</sub>O(g)$

Iron(III)oxide can be reduced by carbon monoxide. Fe₂O₃(s)+ 3CO(g) 2Fe(s)+ 3CO₂(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Which relationship best describes $\Delta$ S° for the following reaction? CO(g)+ H₂O(g) $\to$ CO₂(g)+ H₂(g)

You are given pure samples of pentane,CH₃CH₂CH₂CH₂CH₃(l),and 1,3-pentadiene,CH₂=CHCH=CHCH₃(l).What prediction would you make concerning the standard molar entropies of pentane,S°(pentane)and 1,3-pentadiene,S°(1,3-pentadiene),at 298 K?

The reaction of methane with water to form carbon dioxide and hydrogen is non-spontaneous at 298 K.At what temperature will this system make the transition from non-spontaneous to spontaneous? The data refer to 298 K. CH₄(g)+ 2H₂O(g) CO₂(g)+ 4H₂(g)

A chemical reaction has $\Delta$ G° = 10.0 kJ and $\Delta$ S° = 50.0 J/K a.Calculate $\Delta$ H° for this reaction at 25°C. b.Could this reaction ever be spontaneous? Explain your answer.

Which relationship or statement best describes $\Delta$ S° for the following reaction? C₂H₅OH(l)+ 3O₂(g) $\to$ 2CO₂(g)+ 3H₂O(l)

Which relationship or statement best describes $\Delta$ S° for the following reaction? 2NH₃(g)+ 2ClF₃(g) $\to$ 6HF(g)+ N₂(g)+ Cl₂(g)