Question 1

Which of the following processes have a ΔrS = 0?

Accepted Answer

A) water freezes 
B) isopropyl alcohol vapour condenses 
C) methanol (g,at 555 K)→ methanol (g,at 400 K) 
D) carbon dioxide(g)→ carbon dioxide(s) 
E) H2(g)+ F2(g)→ 2HF(g) 
A) water freezes 
B) isopropyl alcohol vapour condenses 
C) methanol (g,at 555 K)→ methanol (g,at 400 K) 
D) carbon dioxide(g)→ carbon dioxide(s) 
E) H2(g)+ F2(g)→ 2HF(g)

Question 2

Given the following equation, 
$\quad$$\quad$N2O(g)+ NO2(g)→ 3NO(g)$\quad$$\quad$ΔrG° = -23.0 kJ mol-1
Calculate ΔrGo for the following reaction:
$\quad$$\quad$3NO(g)→ N2O(g)+ NO2(g)

Accepted Answer

A) -23.0 kJ mol-1 
B) 69.0 kJ mol-1 
C) -69.0 kJ mol-1 
D) -7.67 kJ mol-1 
E) 23.0 kJ mol-1 
A) -23.0 kJ mol-1 
B) 69.0 kJ mol-1 
C) -69.0 kJ mol-1 
D) -7.67 kJ mol-1 
E) 23.0 kJ mol-1

Question 3

Determine the temperature of a reaction if ΔrG = 42.5 kJ mol-1,ΔrG° = 18.6 kJ mol-1,and Q = 17.7

Accepted Answer

A) 385 K 
B) 522 K 
C) 690 K 
D) 827 K 
E) 1000 K 
A) 385 K 
B) 522 K 
C) 690 K 
D) 827 K 
E) 1000 K

Question 4

Why is heating your home with gas more efficient than heating it with electricity?

Accepted Answer

Heating with gas only requires a one-ste

Question 5

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

Accepted Answer

A) 2NO(g)+ O2(g)→ 2NO2(g) 
B) COCl2(g)→ CO(g)+ Cl2(g) 
C) CH3OH(l)→ CO(g)+ 2H2(g) 
D) NaClO3(s)→ Na+(aq)+ ClO3-(aq) 
E) H2(g)+ Cl2(g)→ 2HCl(g) 
A) 2NO(g)+ O2(g)→ 2NO2(g) 
B) COCl2(g)→ CO(g)+ Cl2(g) 
C) CH3OH(l)→ CO(g)+ 2H2(g) 
D) NaClO3(s)→ Na+(aq)+ ClO3-(aq) 
E) H2(g)+ Cl2(g)→ 2HCl(g)

Question 6

For the following example,what is true about ΔrH and ΔrS? 
$\quad$$\quad$$\quad$$\quad$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 7

Determine the equilibrium constant for the following reaction at 298 K: SO3(g)+ H2O(g)→ H2SO4(l)$\quad$ΔrG° = -90.5 kJ mol-1

Accepted Answer

A) 1.37 × 10-16 
B) 4.78 × 1011 
C) 9.11 × 10-8 
D) 7.31 × 1015 
E) 0.964 
A) 1.37 × 10-16 
B) 4.78 × 1011 
C) 9.11 × 10-8 
D) 7.31 × 1015 
E) 0.964

Question 8

What is "free" energy? Give a fictitious example.

Accepted Answer

Consider a reaction that is exothermic (

Question 9

What is the sign of ΔSuniv for a biological system?

Accepted Answer

A) positive 
B) negative 
C) zero 
D) It depends on the biological system. 
A) positive 
B) negative 
C) zero 
D) It depends on the biological system.

Question 10

Calculate ?rG for the evaporation of methanol at 25°C under nonstandard conditions when $\mathrm { PCH } _ { 3 } \mathrm { OH }$ = 10.0 mbar 
$\quad$$\quad$$\quad$CH3OH(l)? CH3OH(g)

Accepted Answer

A) -7.1 kJ mol-1 
B) +16 kJ mol-1 
C) -11 kJ mol-1 
D) +4.3 kJ mol-1 
E) +5.7 kJ mol-1 
A) -7.1 kJ mol-1 
B) +16 kJ mol-1 
C) -11 kJ mol-1 
D) +4.3 kJ mol-1 
E) +5.7 kJ mol-1

Question 11

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: 
$\quad$$\quad$SO3(g)+ H2O(g)→ H2SO4(l)$\quad$$\quad$$\quad$ΔrG°= -90.5 kJ mol-1
$\quad$$\quad$P(SO3)= 0.20 atm,P(H2O)= 0.88 atm

Accepted Answer

A) +15.9 kJ mol-1 
B) -90.5 kJ mol-1 
C) +51.4 kJ mol-1 
D) -86.2 kJ mol-1 
E) -30.4 kJ mol-1 
A) +15.9 kJ mol-1 
B) -90.5 kJ mol-1 
C) +51.4 kJ mol-1 
D) -86.2 kJ mol-1 
E) -30.4 kJ mol-1

Question 12

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 13

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

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 14

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

Accepted Answer

Spontaneity is a thermodynamic

Question 15

Why can endothermic reactions be spontaneous?

Accepted Answer

Even though an endothermic process requi

Question 16

In the Haber process,ammonia is synthesized from nitrogen and hydrogen: 
$\mathrm { N } _ { 2 }$ (g)+ $3 \mathrm { H } _ { 2 }$ (g)? $2 \mathrm { NH } _ { 3 }$ 
(g) ?rG° at 298 K for this reaction is -33.3 kJ mol-1.The value of ?rG at 298 K for a reaction mixture that consists of 1.7 atm $\mathrm { N } _ { 2 }$ ,1.1 atm $\mathrm { H } _ { 2 }$ ,and 0.55 atm $\mathrm { NH } _ { 3 }$ is ________ kJ mol-1.

Accepted Answer

A) -5.02 × 103 
B) -4.5 
C) -72.2 
D) -35.3 
E) -38.3 
A) -5.02 × 103 
B) -4.5 
C) -72.2 
D) -35.3 
E) -38.3

Question 17

Above what temperature does the following reaction become nonspontaneous? $\quad$$\quad$2H2S(g)+ 3O2(g)→ 2SO2(g)+ 2H2O(g)$\quad$$\quad$ΔrH = -1036 kJ; ΔrS = -153.2 J K-1 mol-1

Accepted Answer

A) 6.762 × 103 K 
B) 158.7 K 
C) 298 K 
D) 67.62 K 
E) 1.587 × 103 K 
A) 6.762 × 103 K 
B) 158.7 K 
C) 298 K 
D) 67.62 K 
E) 1.587 × 103 K

Question 18

Determine the equilibrium constant for the following reaction at 298 K: 
$\quad$Cl(g)+ O3(g)→ ClO(g)+ O2(g)$\quad$$\quad$ΔrG° = - 34.5 kJ mol-1

Accepted Answer

A) 5.66 × 105 
B) 0.986 
C) 8.96 × 10-7 
D) 4.98 × 10-4 
E) 1.12 × 106 
A) 5.66 × 105 
B) 0.986 
C) 8.96 × 10-7 
D) 4.98 × 10-4 
E) 1.12 × 106

Question 19

For a given reaction,?rH = -19.5 kJ mol-1 and ?rS = -55.8 J K-1 mol-1.The reaction will have $\Delta _ { \mathrm { r } } G = 0$ at $\mathrm { K } .$ Assume that ?rH and ?rS do not vary with temperature.

Accepted Answer

A) 2.86 
B) 0.349 
C) 298 
D) 2.86 × 103 
E) 349 
A) 2.86 
B) 0.349 
C) 298 
D) 2.86 × 103 
E) 349

Exam 17: Gibbs Energy and Thermodynamics

Which of the following processes have a ΔrS = 0?

Given the following equation, \quad\quad N2O(g)+ NO2(g)→ 3NO(g) \quad\quad ΔrG° = -23.0 kJ mol-1 Calculate ΔrGo for the following reaction: \quad\quad 3NO(g)→ N2O(g)+ NO2(g)

Determine the temperature of a reaction if ΔrG = 42.5 kJ mol-1,ΔrG° = 18.6 kJ mol-1,and Q = 17.7

Why is heating your home with gas more efficient than heating it with electricity?

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

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

Determine the equilibrium constant for the following reaction at 298 K: SO3(g)+ H2O(g)→ H2SO4(l) \quad ΔrG° = -90.5 kJ mol-1

What is "free" energy? Give a fictitious example.

What is the sign of ΔSuniv for a biological system?

Calculate ?rG for the evaporation of methanol at 25°C under nonstandard conditions when PCH3OH\mathrm { PCH } _ { 3 } \mathrm { OH }PCH3​OH = 10.0 mbar \quad\quad\quad CH3OH(l)? CH3OH(g)

Calculate ΔrG at 298 K under the conditions shown below for the following reaction: \quad\quad SO3(g)+ H2O(g)→ H2SO4(l) \quad\quad\quad ΔrG°= -90.5 kJ mol-1 \quad\quad P(SO3)= 0.20 atm,P(H2O)= 0.88 atm

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

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

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

Why can endothermic reactions be spontaneous?

Above what temperature does the following reaction become nonspontaneous? \quad\quad 2H2S(g)+ 3O2(g)→ 2SO2(g)+ 2H2O(g) \quad\quad ΔrH = -1036 kJ; ΔrS = -153.2 J K-1 mol-1

Determine the equilibrium constant for the following reaction at 298 K: \quad Cl(g)+ O3(g)→ ClO(g)+ O2(g) \quad\quad ΔrG° = - 34.5 kJ mol-1

For a given reaction,?rH = -19.5 kJ mol-1 and ?rS = -55.8 J K-1 mol-1.The reaction will have ΔrG=0\Delta _ { \mathrm { r } } G = 0Δr​G=0 at K.\mathrm { K } .K. Assume that ?rH and ?rS do not vary with temperature.

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Filters

Which of the following processes have a Δ_rS = 0?

Given the following equation, $\quad$ $\quad$ N₂O(g)+ NO₂(g)→ 3NO(g) $\quad$ $\quad$ Δ_rG°= -23.0 kJ mol^-1 Calculate Δ_rG^o for the following reaction: $\quad$ $\quad$ 3NO(g)→ N₂O(g)+ NO₂(g)

Determine the temperature of a reaction if Δ_rG = 42.5 kJ mol^-1,Δ_rG° = 18.6 kJ mol^-1,and Q = 17.7

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

Determine the equilibrium constant for the following reaction at 298 K: SO₃(g)+ H₂O(g)→ H₂SO₄(l) $\quad$ Δ_rG° = -90.5 kJ mol^-1

What is the sign of ΔS_univ for a biological system?

Calculate ?_rG for the evaporation of methanol at 25°C under nonstandard conditions when $\mathrm { PCH } _ { 3 } \mathrm { OH }$ = 10.0 mbar $\quad$ $\quad$ $\quad$ CH₃OH(l)? CH₃OH(g)

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: $\quad$ $\quad$ SO₃(g)+ H₂O(g)→ H₂SO₄(l) $\quad$ $\quad$ $\quad$ Δ_rG°= -90.5 kJ mol^-1 $\quad$ $\quad$ P(SO₃)= 0.20 atm,P(H₂O)= 0.88 atm

Above what temperature does the following reaction become nonspontaneous? $\quad$ $\quad$ 2H₂S(g)+ 3O₂(g)→ 2SO₂(g)+ 2H₂O(g) $\quad$ $\quad$ Δ_rH = -1036 kJ; Δ_rS = -153.2 J K^-1 mol^-1

Determine the equilibrium constant for the following reaction at 298 K: $\quad$ Cl(g)+ O₃(g)→ ClO(g)+ O₂(g) $\quad$ $\quad$ Δ_rG° = - 34.5 kJ mol^-1

For a given reaction,?_rH = -19.5 kJ mol^-1 and ?_rS = -55.8 J K^-1 mol^-1.The reaction will have $\Delta _ { \mathrm { r } } G = 0$ at $\mathrm { K } .$ Assume that ?_rH and ?_rS do not vary with temperature.