Question 1

What is k in Boltzmann's formula,S = k ln W?

Accepted Answer

A) the degeneracy of the state 
B) the equilibrium constant for the process 
C) the universal gas constant divided by Avogadro's number 
D) the universal gas constant times Avogadro's number 
A) the degeneracy of the state 
B) the equilibrium constant for the process 
C) the universal gas constant divided by Avogadro's number 
D) the universal gas constant times Avogadro's number

Question 2

Which has the highest entropy in each set?
I.H2O(s),H2O(l),H2O(g)at 0.1°C,4.58 atm
II.H2O(l)at 0°C,H2O(l)at 25°C,H2O(l)at 100°C (all at 1.0 atm pressure)

Accepted Answer

A) H2O(l)in set I and H2O(l)at 0°C in set II 
B) H2O(s)in set I and H2O(l)at 100°C in set II 
C) H2O(g)in set I and H2O(l)at 0°C in set II 
D) H2O(g)in set I and H2O(l)at 100°C in set II 
A) H2O(l)in set I and H2O(l)at 0°C in set II 
B) H2O(s)in set I and H2O(l)at 100°C in set II 
C) H2O(g)in set I and H2O(l)at 0°C in set II 
D) H2O(g)in set I and H2O(l)at 100°C in set II

Question 3

Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions.
Reaction 1: S(s,rhombic)+ O2(g)→ SO2(g)
Reaction 2: 2 SO2(g)+ O2(g)→ 2 SO3(g)

Accepted Answer

A) ΔS° is positive for both reactions. 
B) ΔS° is positive for reaction 1 but negative for reaction 2. 
C) ΔS° is positive for reaction 2 but negative for reaction 1. 
D)  Δs° is positive for both reactions. 
A) ΔS° is positive for both reactions. 
B) ΔS° is positive for reaction 1 but negative for reaction 2. 
C) ΔS° is positive for reaction 2 but negative for reaction 1. 
D)  Δs° is positive for both reactions.

Question 4

A positive value of ΔG°f for a solid compound at 25°C means the

Accepted Answer

A) compound cannot exist at 25°C and 1 atm. 
B) compound must be a liquid or a gas at 25°C and 1 atm. 
C) process of forming the compound from the elements is exothermic. 
D) process of forming the compound from the stable elements at 25°C and 1 atm is nonspontaneous. 
A) compound cannot exist at 25°C and 1 atm. 
B) compound must be a liquid or a gas at 25°C and 1 atm. 
C) process of forming the compound from the elements is exothermic. 
D) process of forming the compound from the stable elements at 25°C and 1 atm is nonspontaneous.

Question 5

Assume a heteronuclear diatomic molecule,AB,forms a one-dimensional crystal by lining up along the x-axis.Also assume that each molecule can only have one of six possible orientations,corresponding to atom A facing in either the positive or negative direction along the x-,y-,or z-axis.If the molecules are arranged randomly in the six directions,the molar entropy at absolute zero should be

Accepted Answer

A) R ln 6. 
B) R ln 66. 
C) R ln 6! 
D) 0) 
A) R ln 6. 
B) R ln 66. 
C) R ln 6! 
D) 0)

Question 6

For the reaction N2(g)+ 2 O2(g)→ 2 NO2(g),ΔH° = 66.4 kJ/mol and ΔS° = -121.5 J/K.Is there a temperature at which the spontaneity of this reaction be changed,either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so,estimate the temperature.

Accepted Answer

This reaction is non

Question 7

-The figure above represents the nonspontaneous reaction O2(g)→ 2O(g).What are the signs (+ or -)of ΔH,ΔS,and ΔG for this process?

Accepted Answer

A) ΔH = +,ΔS = +,ΔG = + 
B) ΔH = +,ΔS = +,ΔG = - 
C) ΔH = -,ΔS = -,ΔG = + 
D) ΔH = -,ΔS = -,ΔG = - 
A) ΔH = +,ΔS = +,ΔG = + 
B) ΔH = +,ΔS = +,ΔG = - 
C) ΔH = -,ΔS = -,ΔG = + 
D) ΔH = -,ΔS = -,ΔG = -

Question 8

A reaction has ΔH° = -60.9 kJ/mol and ΔS° = 266.6 J/K.Is this reaction spontaneous or nonspontaneous? At what temperature (if any)can the spontaneity be reversed?

Accepted Answer

A) nonspontaneous,can be made spontaneous at 228 K 
B) nonspontaneous,cannot be made spontaneous at any temperature 
C) spontaneous,can be made nonspontaneous at 228 K 
D) spontaneous,cannot be made nonspontaneous at any temperature 
A) nonspontaneous,can be made spontaneous at 228 K 
B) nonspontaneous,cannot be made spontaneous at any temperature 
C) spontaneous,can be made nonspontaneous at 228 K 
D) spontaneous,cannot be made nonspontaneous at any temperature

Question 9

ΔG = ΔG° for a reaction

Accepted Answer

A) if Q = K. 
B) if Q = 1. 
C) at STP. 
D) at the start of the reaction. 
A) if Q = K. 
B) if Q = 1. 
C) at STP. 
D) at the start of the reaction.

Question 10

-According to the diagram above,

Accepted Answer

A) ΔG° is positive and the equilibrium composition is rich in products. 
B) ΔG° is positive and the equilibrium composition is rich in reactants. 
C) ΔG° is negative and the equilibrium composition is rich in products. 
D) ΔG° is negative and the equilibrium composition is rich is reactants. 
A) ΔG° is positive and the equilibrium composition is rich in products. 
B) ΔG° is positive and the equilibrium composition is rich in reactants. 
C) ΔG° is negative and the equilibrium composition is rich in products. 
D) ΔG° is negative and the equilibrium composition is rich is reactants.

Question 11

What is K if ΔG° = -18.0 kJ for a reaction at 25°?

Accepted Answer

A) 1)4 × 103 
B) 1)2 × 102 
C) 8)1 × 10-3 
D) 7)3 × 10-4 
A) 1)4 × 103 
B) 1)2 × 102 
C) 8)1 × 10-3 
D) 7)3 × 10-4

Question 12

If ΔG is small and positive,

Accepted Answer

A) the forward reaction is spontaneous and the system is far from equilibrium. 
B) the forward reaction is spontaneous and the system is near equilibrium. 
C) the reverse reaction is spontaneous and the system is far from equilibrium. 
D) the reverse reaction is spontaneous and the system is near equilibrium. 
A) the forward reaction is spontaneous and the system is far from equilibrium. 
B) the forward reaction is spontaneous and the system is near equilibrium. 
C) the reverse reaction is spontaneous and the system is far from equilibrium. 
D) the reverse reaction is spontaneous and the system is near equilibrium.

Question 13

For a process to be at equilibrium,it is necessary that

Accepted Answer

A) ΔSsys = ΔSsurr. 
B) ΔSsys = -ΔSsurr. 
C) ΔSsys = 0. 
D) ΔSsys = 0 and ΔSsurr = 0. 
A) ΔSsys = ΔSsurr. 
B) ΔSsys = -ΔSsurr. 
C) ΔSsys = 0. 
D) ΔSsys = 0 and ΔSsurr = 0.

Question 14

Which provides the greatest increase in entropy?

Accepted Answer

A) H2O (s,0°
C) → H2O (l,0°
C)  
B) H2O (l,0°
C) → H2O (l,25°
C)  
C) H2O (g,0.1°
C) → H2O (s,0.1°
C)  
D) H2O (l,100°
C) → H2O (g,100°
C)  
A) H2O (s,0°
C) → H2O (l,0°
C)  
B) H2O (l,0°
C) → H2O (l,25°
C)  
C) H2O (g,0.1°
C) → H2O (s,0.1°
C)  
D) H2O (l,100°
C) → H2O (g,100°
C)

Question 15

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

Accepted Answer

A) C10H22(s) 
B) C10H22(l) 
C) C14H30(s) 
D) C14H30OH(l) 
A) C10H22(s) 
B) C10H22(l) 
C) C14H30(s) 
D) C14H30OH(l)

Question 16

What is W in Boltzmann's formula,S = k ln W?

Accepted Answer

A) a fraction indicating the probability of obtaining a result 
B) a random number 
C) the number of ways of obtaining the state 
D) the work times Avogadro's number 
A) a fraction indicating the probability of obtaining a result 
B) a random number 
C) the number of ways of obtaining the state 
D) the work times Avogadro's number

Question 17

For which process is the sign of ΔS negative in the system?

Accepted Answer

A) 2 H2(g)+ O2(g)→ 2 H2O(g) 
B) 2 H2O(l)+ 2 K(s)→ 2 K+(aq)+2 OH-(aq)+ H2(g) 
C) H2O(s)→ H2O(g) 
D) H2O(l)→ H2O(g) 
A) 2 H2(g)+ O2(g)→ 2 H2O(g) 
B) 2 H2O(l)+ 2 K(s)→ 2 K+(aq)+2 OH-(aq)+ H2(g) 
C) H2O(s)→ H2O(g) 
D) H2O(l)→ H2O(g)

Question 18

Chemical and physical changes can be classified as spontaneous or nonspontaneous.At 25°C and
1 atm pressure the decomposition of water into hydrogen and oxygen is classified as ________,and the melting of ice is classified as ________.

Accepted Answer

nonspontan

Question 19

Which of the following are unstable with respect to their constituent elements at 25°C?

Accepted Answer

A) C8H18(l),CH3OH(l) 
B) C8H18(l),C2H2(g) 
C) C2H2(g) 
D) CH3OH(l) 
A) C8H18(l),CH3OH(l) 
B) C8H18(l),C2H2(g) 
C) C2H2(g) 
D) CH3OH(l)

Question 20

Consider the reaction 2A(g)⇌ AS1U1B12S1U1B0(g).The following pictures represent two possible initial states and the equilibrium state of the system.  
-For initial state 2 what is the relationship between the reaction quotient,Qp,and the equilibrium constant,Kp?

Accepted Answer

A) Qp p 
B) Qp = Kp = 1 
C) Qp = Kp ≠ 1 
D) Qp > Kp 
A) Qp p 
B) Qp = Kp = 1 
C) Qp = Kp ≠ 1 
D) Qp > Kp

Exam 16: Thermodynamics: Entropy, free Energy, and Equilibrium

What is k in Boltzmann's formula,S = k ln W?

Which has the highest entropy in each set? I.H2O(s),H2O(l),H2O(g)at 0.1°C,4.58 atm II.H2O(l)at 0°C,H2O(l)at 25°C,H2O(l)at 100°C (all at 1.0 atm pressure)

Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions. Reaction 1: S(s,rhombic)+ O2(g)→ SO2(g) Reaction 2: 2 SO2(g)+ O2(g)→ 2 SO3(g)

A positive value of ΔG°f for a solid compound at 25°C means the

For the reaction N2(g)+ 2 O2(g)→ 2 NO2(g),ΔH° = 66.4 kJ/mol and ΔS° = -121.5 J/K.Is there a temperature at which the spontaneity of this reaction be changed,either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so,estimate the temperature.

-The figure above represents the nonspontaneous reaction O2(g)→ 2O(g).What are the signs (+ or -)of ΔH,ΔS,and ΔG for this process?

A reaction has ΔH° = -60.9 kJ/mol and ΔS° = 266.6 J/K.Is this reaction spontaneous or nonspontaneous? At what temperature (if any)can the spontaneity be reversed?

ΔG = ΔG° for a reaction

-According to the diagram above,

What is K if ΔG° = -18.0 kJ for a reaction at 25°?

If ΔG is small and positive,

For a process to be at equilibrium,it is necessary that

Which provides the greatest increase in entropy?

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

What is W in Boltzmann's formula,S = k ln W?

For which process is the sign of ΔS negative in the system?

Chemical and physical changes can be classified as spontaneous or nonspontaneous.At 25°C and 1 atm pressure the decomposition of water into hydrogen and oxygen is classified as ________,and the melting of ice is classified as ________.

Which of the following are unstable with respect to their constituent elements at 25°C?

Consider the reaction 2A(g)⇌ A2(g).The following pictures represent two possible initial states and the equilibrium state of the system. -For initial state 2 what is the relationship between the reaction quotient,Qp,and the equilibrium constant,Kp?

Chemistry: Matter and Measurement

Atoms, molecules, and Ions

Formulas, equations, and Moles

Reactions in Aqueous Solutions

Periodicity and the Atomic Structure of Atoms

Ionic Bonds and Some Main-Group Chemistry

Covalent Bonds and Molecular Structure

Thermochemistry: Chemical Energy

Gases: Their Properties and Behavior

Liquids,solids,and Phase Changes

Solutions and Their Properties

Chemical Kinetics

Chemical Equilibrium

Aqueous Equilibria: Acids and Bases

Applications of Aqueous Equilibria

Electrochemistry

Hydrogen, oxygen, and Water

The Main-Group Elements

Transition Elements and Coordination Chemistry

Metals and Solid-State Materials

Nuclear Chemistry

Organic and Biological Chemistry

Filters

Which has the highest entropy in each set? I.H₂O(s),H₂O(l),H₂O(g)at 0.1°C,4.58 atm II.H₂O(l)at 0°C,H₂O(l)at 25°C,H₂O(l)at 100°C (all at 1.0 atm pressure)

Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions. Reaction 1: S(s,rhombic)+ O₂(g)→ SO₂(g) Reaction 2: 2 SO₂(g)+ O₂(g)→ 2 SO₃(g)

A positive value of ΔG°_f for a solid compound at 25°C means the

For the reaction N₂(g)+ 2 O₂(g)→ 2 NO₂(g),ΔH° = 66.4 kJ/mol and ΔS° = -121.5 J/K.Is there a temperature at which the spontaneity of this reaction be changed,either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so,estimate the temperature.

-The figure above represents the nonspontaneous reaction O₂(g)→ 2O(g).What are the signs (+ or -)of ΔH,ΔS,and ΔG for this process?

Chemical and physical changes can be classified as spontaneous or nonspontaneous.At 25°C and 1 atm pressure the decomposition of water into hydrogen and oxygen is classified as ,and the melting of ice is classified as .

Consider the reaction 2A(g)⇌ A₂(g).The following pictures represent two possible initial states and the equilibrium state of the system. -For initial state 2 what is the relationship between the reaction quotient,Q_p,and the equilibrium constant,K_p?