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.

A) -35800 B) -173.4 C) 35800 D) -101.7 E) -274.2 A) -35800 B) -173.4 C) 35800 D) -101.7 E) -274.2

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

A) -1228.7 B) +1228.7 C) -940.1 D) +940.1 E) +0.00 A) -1228.7 B) +1228.7 C) -940.1 D) +940.1 E) +0.00

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

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

Exam 19: Chemical Thermodynamics

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.

(Multiple Choice)

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Question 81

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.

(Multiple Choice)

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Question 82

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.

(Short Answer)

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Question 83

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?

(Multiple Choice)

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Question 84

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?

(Multiple Choice)

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Question 85

The second law of thermodynamics states that __________.

(Multiple Choice)

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Question 86

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

(Multiple Choice)

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Question 87

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

(Multiple Choice)

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Question 88

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

(Multiple Choice)

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Question 89

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

(Multiple Choice)

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Question 90

When a system is at equilibrium, __________.

(Multiple Choice)

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Question 91

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 __________.

(Multiple Choice)

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Question 92

For an isothermal process, ΔS = __________.

(Multiple Choice)

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Question 93

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

(Short Answer)

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Question 94

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

(Multiple Choice)

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Question 95

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.

(Multiple Choice)

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Question 96

ΔS is negative for the reaction __________.

(Multiple Choice)

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Question 97

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.

(Multiple Choice)

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Question 98

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.

(Short Answer)

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Question 99

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

(Multiple Choice)

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Question 100

Showing 81 - 100 of 120

Exam 19: Chemical Thermodynamics

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.

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.

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.

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?

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?

The second law of thermodynamics states that __________.

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

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

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

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

When a system is at equilibrium, __________.

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 __________.

For an isothermal process, ΔS = __________.

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

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

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.

ΔS is negative for the reaction __________.

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.

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.

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

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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.

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.

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?

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

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

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

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 __________.

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

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.