Question 1

Calculate ΔG° for the autoionization of water at 25°C. Kw = 1.0 × 10-14

Accepted Answer

Question 2

The value of ΔH° for the decomposition of POCl3 into its constituent elements, 2POCl3 (g) → P2 (g) + O2 (g) + 3Cl2 (g) 
Is __________ kJ/mol.

Accepted Answer

A)  -1228.7
B)  +1228.7
C)  -940.1
D)  +940.1
E)  +0.00F) C) and D)
G) A) and E)

Question 3

The second law of thermodynamics states that __________.

Accepted Answer

A)  ΔE = q + w
B)   rev/T at constant temperature" class="answers-bank-image d-inline" rel="preload" >
C)  for any spontaneous process, the entropy of the universe increases
D)  the entropy of a pure crystalline substance is zero at absolute zero
E)  ΔS = qrev/T at constant temperatureF) A) and E)
G) B) and D)

Question 4

Of the following, only __________ is not a state function.

Accepted Answer

A)  S
B)  H
C)  q
D)  E
E)  TF) A) and E)
G) A) and B)

Question 5

Which reaction produces an increase in the entropy of the system?

Accepted Answer

A)  Ag+ (aq) + Cl- (aq) → AgCl (s) 
B)  CO2 (s) → CO2 (g) 
C)  H2 (g) + Cl2 (g) → 2HCl (g) 
D)  N2 (g) + 3H2 (g) → 2NH3 (g) 
E)  H2O (l) → H2O (s) F) B) and E)
G) C) and D)

Question 6

Find the temperature (in K)above which a reaction with a ΔH of 53.00 kJ/mol and a ΔS of 100.0 J/K∙ mol becomes spontaneous.

Accepted Answer

The answer of Find the temperature (in K)above which a...

Question 7

For the reaction C(s) + H2O(g) → CO(g) + H2(g) 
ΔH° = 131.3 kJ/mol and ΔS° = 127.6 J/K ∙ mol at 298 K. At temperatures greater than __________°C this reaction is spontaneous under standard conditions.

Accepted Answer

A)  273
B)  325
C)  552
D)  756
E)  1029F) A) and C)
G) B) and D)

Question 8

Consider a pure crystalline solid that is heated from absolute zero to a temperature above the boiling point of the liquid. Which of the following processes produces the greatest increase in the entropy of the substance?

Accepted Answer

A)  melting the solid
B)  heating the liquid
C)  heating the gas
D)  heating the solid
E)  vaporizing the liquidF) A) and E)
G) A) and C)

Question 9

The standard Gibbs free energy of formation of __________ is zero. (a) H2O (l) 
(b) O (g) 
(c) I2 (s)

Accepted Answer

A)  (a) only
B)  (b) only
C)  (c) only
D)  (b) and (c) 
E)  (a) , (b) , and (c) F) C) and D)
G) A) and C)

Question 10

For an isothermal process, ΔS = __________.

Accepted Answer

A)  q
B)  qrev/T
C)  qrev
D)  Tqrev
E)  q + wF) A) and B)
G) B) and C)

Question 11

The value of ΔG° at 25°C for the following reaction: C2H4 (g) + H2 (g) → C2H6 (g) 
Is __________ kJ/mol. At 298 K, ΔH° for this reaction is -137.5 kJ/mol, and ΔS° is +120.5 J/K.

Accepted Answer

A)  -35800
B)  -173.4
C)  35800
D)  -101.7
E)  -274.2F) A) and B)
G) A) and C)

Question 12

The value of ΔS° for the decomposition of phosphorous trichloride into its constituent elements, 2PCl3 (g) → P2 (g) + 3Cl2( g) 
Is __________ J/K∙ mol.

Accepted Answer

A)  -311.7
B)  +311.7
C)  +263.6
D)  +129.4
E)  -129.4F) C) and D)
G) B) and C)

Question 13

The normal boiling point of ethanol (C2H5OH) is 78.3°C and its molar enthalpy of vaporization is 38.56 kJ/mol. What is the change in entropy in the system in J/K when 97.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point?

Accepted Answer

A)  330
B)  1038
C)  -330
D)  -1038
E)  -231F) C) and E)
G) A) and E)

Question 14

The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s, rhombic) + O2 (g) → SO2 (g) 
Is __________ kJ/mol.

Accepted Answer

A)  +269.9
B)  -269.9
C)  +0.00
D)  -11.6
E)  +11.6F) C) and E)
G) A) and D)

Question 15

Consider the reaction: FeO (s) + Fe (s) + O2 (g) → Fe2O3 (s) 
Given the following table of thermodynamic data at 298 K: 2 (g) → Fe2O3 (s)  Given the following table of thermodynamic data at 298 K:   The value K for the reaction at 25°C is __________. A) 370 B) 5.9 × 104 C) 3.8 × 10-14 D) 7.1 × 1085 E) 8.1 × 1019" class="answers-bank-image d-inline" rel="preload" > The value K for the reaction at 25°C is __________.

Accepted Answer

A)  370
B)  5.9 × 104
C)  3.8 × 10-14
D)  7.1 × 1085
E)  8.1 × 1019F) B) and D)
G) B) and E)

Question 16

ΔS is negative for the reaction __________.

Accepted Answer

A)  2SO2 (g) + O2 (g) → 2SO3 (g) 
B)  NH4Cl (s) → NH3 (g) + HCl (g) 
C)  PbCl2 (s) → Pb2+ (aq) + 2Cl- (aq) 
D)  2C (s) + O2 (g) → 2CO2 (g) 
E)  H2O (l) → H2O (g) F) C) and E)
G) A) and E)

Question 17

Consider the reaction: NH3 (g) + HCl (g) → NH4Cl (s) 
Given the following table of thermodynamic data, 3 (g) + HCl (g) → NH4Cl (s)  Given the following table of thermodynamic data,   determine the temperature (in °C) above which the reaction is nonspontaneous. A) This reaction is spontaneous at all temperatures. B) 618.1 C) 432.8 D) 345.0 E) 1235" class="answers-bank-image d-inline" rel="preload" > determine the temperature (in °C) above which the reaction is nonspontaneous.

Accepted Answer

A)  This reaction is spontaneous at all temperatures.
B)  618.1
C)  432.8
D)  345.0
E)  1235F) B) and C)
G) C) and D)

Question 18

When a system is at equilibrium, __________.

Accepted Answer

A)  the reverse process is spontaneous but the forward process is not
B)  the forward and the reverse processes are both spontaneous
C)  the forward process is spontaneous but the reverse process is not
D)  the process is not spontaneous in either direction
E)  both forward and reverse processes have stoppedF) A) and B)
G) B) and D)

Question 19

Of the following, the entropy of gaseous __________ is the largest at 25°C and 1 atm.

Accepted Answer

A)  CH3OH
B)  C2H5OH
C)  C3H7OH
D)  CH4
E)  C4H10F) A) and E)
G) A) and B)

Question 20

Find the temperature (in K)above which a reaction with a ΔH of 123.0 kJ/mol and a ΔS of 90.00 J/K∙ mol becomes spontaneous.

Accepted Answer

The answer of Find the temperature (in K)above which a...

Exam 19: Chemical Thermodynamics

For an isothermal process, ΔS = __________.

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The value of ΔS° for the decomposition of phosphorous trichloride into its constituent elements, 2PCl3 (g) → P2 (g) + 3Cl2( g) Is __________ J/K∙ mol.

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Calculate ΔG° for the autoionization of water at 25°C. Kw = 1.0 × 10-14

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Of the following, the entropy of gaseous __________ is the largest at 25°C and 1 atm.

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The second law of thermodynamics states that __________.

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Of the following, only __________ is not a state function.

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The standard Gibbs free energy of formation of __________ is zero. (a) H2O (l) (b) O (g) (c) I2 (s)

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The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s, rhombic) + O2 (g) → SO2 (g) Is __________ kJ/mol.

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For the reaction C(s) + H2O(g) → CO(g) + H2(g) ΔH° = 131.3 kJ/mol and ΔS° = 127.6 J/K ∙ mol at 298 K. At temperatures greater than __________°C this reaction is spontaneous under standard conditions.

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ΔS is negative for the reaction __________.

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Find the temperature (in K)above which a reaction with a ΔH of 123.0 kJ/mol and a ΔS of 90.00 J/K∙ mol becomes spontaneous.

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Consider the reaction: NH3 (g) + HCl (g) → NH4Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

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When a system is at equilibrium, __________.

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Consider a pure crystalline solid that is heated from absolute zero to a temperature above the boiling point of the liquid. Which of the following processes produces the greatest increase in the entropy of the substance?

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The value of ΔH° for the decomposition of POCl3 into its constituent elements, 2POCl3 (g) → P2 (g) + O2 (g) + 3Cl2 (g) Is __________ kJ/mol.

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The normal boiling point of ethanol (C2H5OH) is 78.3°C and its molar enthalpy of vaporization is 38.56 kJ/mol. What is the change in entropy in the system in J/K when 97.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point?

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Which reaction produces an increase in the entropy of the system?

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The value of ΔG° at 25°C for the following reaction: C2H4 (g) + H2 (g) → C2H6 (g) Is __________ kJ/mol. At 298 K, ΔH° for this reaction is -137.5 kJ/mol, and ΔS° is +120.5 J/K.

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Find the temperature (in K)above which a reaction with a ΔH of 53.00 kJ/mol and a ΔS of 100.0 J/K∙ mol becomes spontaneous.

Correct AnswerverifiedShow Answer

Consider the reaction: FeO (s) + Fe (s) + O2 (g) → Fe2O3 (s) Given the following table of thermodynamic data at 298 K: The value K for the reaction at 25°C is __________.

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The value of ΔS° for the decomposition of phosphorous trichloride into its constituent elements, 2PCl₃(g) → P₂(g) + 3Cl₂( g) Is __________ J/K∙ mol.

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Calculate ΔG° for the autoionization of water at 25°C. K_w = 1.0 × 10^-14

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The standard Gibbs free energy of formation of __________ is zero. (a) H₂O (l) (b) O (g) (c) I₂ (s)

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The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s, rhombic) + O₂ (g) → SO₂ (g) Is __________ kJ/mol.

Correct Answer
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For the reaction C(s) + H₂O(g) → CO(g) + H₂(g) ΔH° = 131.3 kJ/mol and ΔS° = 127.6 J/K ∙ mol at 298 K. At temperatures greater than __________°C this reaction is spontaneous under standard conditions.

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Consider the reaction: NH₃ (g) + HCl (g) → NH₄Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

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The value of ΔH° for the decomposition of POCl₃ into its constituent elements, 2POCl₃ (g) → P₂ (g) + O₂ (g) + 3Cl₂ (g) Is __________ kJ/mol.

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The normal boiling point of ethanol (C₂H₅OH) is 78.3°C and its molar enthalpy of vaporization is 38.56 kJ/mol. What is the change in entropy in the system in J/K when 97.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point?

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Correct Answer
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The value of ΔG° at 25°C for the following reaction: C₂H₄ (g) + H₂ (g) → C₂H₆ (g) Is __________ kJ/mol. At 298 K, ΔH° for this reaction is -137.5 kJ/mol, and ΔS° is +120.5 J/K.

Correct Answer
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Correct Answer
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Consider the reaction: FeO (s) + Fe (s) + O₂ (g) → Fe₂O₃ (s) Given the following table of thermodynamic data at 298 K: The value K for the reaction at 25°C is __________.

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