Question 1

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

Accepted Answer

A) ΔS°rxn > 0,ΔH°rxn > 0 
B) ΔS°rxn > 0,ΔH°rxn rxn rxn rxn rxn > 0 
E) ΔS°rxn = 0,ΔH°rxn = 0 
A) ΔS°rxn > 0,ΔH°rxn > 0 
B) ΔS°rxn > 0,ΔH°rxn rxn rxn rxn rxn > 0 
E) ΔS°rxn = 0,ΔH°rxn = 0

Question 2

Which is the thermodynamic condition for a spontaneous process at constant T and P?

Accepted Answer

A) ΔS > 0 
B) ΔS  0 
E) ΔG° = 0 
A) ΔS > 0 
B) ΔS  0 
E) ΔG° = 0

Question 3

For a chemical reaction to be spontaneous only at high temperatures,which conditions must be met?

Accepted Answer

A) ΔS° > 0,ΔH° > 0 
B) ΔS° > 0,ΔH°  0 
E) ΔG° > 0 
A) ΔS° > 0,ΔH° > 0 
B) ΔS° > 0,ΔH°  0 
E) ΔG° > 0

Question 4

When a sky diver free-falls through the air,the process is

Accepted Answer

A) nonspontaneous because he is accelerating due to the force applied by gravity. 
B) nonspontaneous because he is losing potential energy. 
C) nonspontaneous because he had planned the jump for two weeks. 
D) spontaneous. 
E) in equilibrium. 
A) nonspontaneous because he is accelerating due to the force applied by gravity. 
B) nonspontaneous because he is losing potential energy. 
C) nonspontaneous because he had planned the jump for two weeks. 
D) spontaneous. 
E) in equilibrium.

Question 5

Which is always true for an exothermic process?

Accepted Answer

A) qsys > 0,ΔSsurr sys surr > 0 C) qsys surr sys > 0,ΔSsurr > 0 E) w < 0 A) qsys > 0,ΔSsurr sys surr > 0 C) qsys surr sys > 0,ΔSsurr > 0 E) w < 0

Question 6

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

Question 7

Is the following process spontaneous?

Accepted Answer

A) Yes,because ΔH > 0. B) No,because ΔH 0. D) No,because ΔS < 0. E) It's impossible to tell without knowing the temperature of the system. A) Yes,because ΔH > 0. B) No,because ΔH 0. D) No,because ΔS < 0. E) It's impossible to tell without knowing the temperature of the system.

Question 8

How many types of rotations does a diatomic molecule exhibit?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 4 
A) 0 
B) 1 
C) 2 
D) 3 
E) 4

Question 9

A spontaneous endothermic reaction always

Accepted Answer

A) causes the surroundings to get colder. 
B) bursts into flame. 
C) requires a spark to initiate it. 
D) releases heat to the surroundings. 
A) causes the surroundings to get colder. 
B) bursts into flame. 
C) requires a spark to initiate it. 
D) releases heat to the surroundings.

Question 10

The absolute standard entropy of atom X(g)is 100 J/K • mol.Which is a reasonable value for the absolute standard entropy of X2(g)?

Accepted Answer

A) 200 J/K • mol 
B) 170 J/K • mol 
C) 100 J/K • mol 
D) 80 J/K • mol 
E) 50 J/K • mol 
A) 200 J/K • mol 
B) 170 J/K • mol 
C) 100 J/K • mol 
D) 80 J/K • mol 
E) 50 J/K • mol

Question 11

Ozone (O3)in the atmosphere can react with nitric oxide (NO)as follows. O3(g)+ NO(g)→ NO2(g)+ O2(g).ΔH°rxn = -199 kJ/mol,ΔS°rxn = -4.1 J/K • mol
What is ΔG°rxn for this reaction at 25°C?

Accepted Answer

A) 1020 kJ/mol 
B) -1.22 × 103 kJ/mol 
C) 2.00 × 103 kJ/mol 
D) -1.42 × 103 kJ/mol 
E) -198 kJ/mol 
A) 1020 kJ/mol 
B) -1.22 × 103 kJ/mol 
C) 2.00 × 103 kJ/mol 
D) -1.42 × 103 kJ/mol 
E) -198 kJ/mol

Question 12

How many types of vibrations does a diatomic molecule exhibit?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 4 
A) 0 
B) 1 
C) 2 
D) 3 
E) 4

Question 13

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 
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 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 wil

Question 15

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) 
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 16

Which of these species has the highest entropy (S°)at 25°C?

Accepted Answer

A) CH3OH(l) 
B) CO(g) 
C) MgCO3(s) 
D) H2O(l) 
E) Si(s) 
A) CH3OH(l) 
B) CO(g) 
C) MgCO3(s) 
D) H2O(l) 
E) Si(s)

Question 17

Which thermodynamical property is a measure of the disorder in the system?

Accepted Answer

The answer of Which thermodynamical property is a measure of...

Question 18

HI has a normal boiling point of -35.4°C,and its ΔHvap is 21.16 kJ/mol.What is the molar entropy of vaporization (ΔSvap)of HI?

Accepted Answer

A) 598 J/K • mol 
B) 68.6 J/K • mol 
C) 75.2 J/K • mol 
D) 0.068 J/K • mol 
E) 89.0 J/K • mol 
A) 598 J/K • mol 
B) 68.6 J/K • mol 
C) 75.2 J/K • mol 
D) 0.068 J/K • mol 
E) 89.0 J/K • mol

Question 19

Which is necessary for a process to be spontaneous?

Accepted Answer

A) ΔHsys sys > 0 
C) ΔSsurr univ > 0 
E) ΔGsys = 0 
A) ΔHsys sys > 0 
C) ΔSsurr univ > 0 
E) ΔGsys = 0

Question 20

Which has the largest entropy?

Accepted Answer

A) C (diamond) 
B) C (graphite) 
C) H2O(l) 
D) F2(l) 
E) O2(g) 
A) C (diamond) 
B) C (graphite) 
C) H2O(l) 
D) F2(l) 
E) O2(g)

Exam 18: Entropy Free Energy and Equilibrium

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

Which is the thermodynamic condition for a spontaneous process at constant T and P?

For a chemical reaction to be spontaneous only at high temperatures,which conditions must be met?

When a sky diver free-falls through the air,the process is

Which is always true for an exothermic process?

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

Is the following process spontaneous?

How many types of rotations does a diatomic molecule exhibit?

A spontaneous endothermic reaction always

The absolute standard entropy of atom X(g)is 100 J/K • mol.Which is a reasonable value for the absolute standard entropy of X2(g)?

Ozone (O3)in the atmosphere can react with nitric oxide (NO)as follows. O3(g)+ NO(g)→ NO2(g)+ O2(g).ΔH°rxn = -199 kJ/mol,ΔS°rxn = -4.1 J/K • mol What is ΔG°rxn for this reaction at 25°C?

How many types of vibrations does a diatomic molecule exhibit?

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

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.

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

Which of these species has the highest entropy (S°)at 25°C?

Which thermodynamical property is a measure of the disorder in the system?

HI has a normal boiling point of -35.4°C,and its ΔHvap is 21.16 kJ/mol.What is the molar entropy of vaporization (ΔSvap)of HI?

Which is necessary for a process to be spontaneous?

Which has the largest entropy?

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The absolute standard entropy of atom X(g)is 100 J/K • mol.Which is a reasonable value for the absolute standard entropy of X₂(g)?

Ozone (O₃)in the atmosphere can react with nitric oxide (NO)as follows. O₃(g)+ NO(g)→ NO₂(g)+ O₂(g).ΔH°_rxn = -199 kJ/mol,ΔS°_rxn = -4.1 J/K • mol What is ΔG°_rxn for this reaction at 25°C?

HI has a normal boiling point of -35.4°C,and its ΔH_vap is 21.16 kJ/mol.What is the molar entropy of vaporization (ΔS_vap)of HI?