Question 1

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 2

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO2 (g)  → S (s, rhombic)  + O2 (g) 
Is ________ J/K ∙ mol.

Accepted Answer

A)  +485.4
B)  +248.5
C)  -11.6
D)  -248.5
E)  +11.6F) C) and D)
G) A) and B)

Question 3

The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements, CaCl2 (s)  → Ca (s)  + Cl2 (g) 
Is ________ kJ/mol.

Accepted Answer

A)  -795.8
B)  +795.8
C)  +763.7
D)  +748.1
E)  -748.1F) A) and B)
G) A) and C)

Question 4

Which of the following statements is true?

Accepted Answer

A)  Processes that are spontaneous in one direction are spontaneous in the opposite direction.
B)  Processes are spontaneous because they occur at an observable rate.
C)  Spontaneity can depend on the temperature.
D)  All of the statements are true.E) A) and D)
F) A) and C)

Question 5

ΔS is positive for the reaction ________.

Accepted Answer

A)  CaO (s)  + CO2 (g)  → CaCO3 (s) 
B)  N2 (g)  + 3H2 (g)  → 2NH3 (g) 
C)  2SO3 (g)  → 2SO2 (g)  + O2 (g) 
D)  Ag+ (aq)  + Cl- (aq)  → AgCl (s) 
E)  H2O (l)  → H2O (s) F) B) and E)
G) None of the above

Question 6

For the reaction 2 C4H10 (g)  + 13 O2 (g) → 8 CO2 (g)  + 10 H2O (g) 
ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is ________.

Accepted Answer

A)  spontaneous at all temperatures
B)  spontaneous only at high temperature
C)  spontaneous only at low temperature
D)  nonspontaneous at all temperatures
E)  unable to determine without more informationF) B) and D)
G) None of the above

Question 7

For a given reaction with ΔH = -28.1 kJ/mol, the ΔG = 0 at 372 K. The value of ΔS must be ________ J/K-mol, assuming that ΔH and ΔS do not vary with temperature.

Accepted Answer

A)  -75.5
B)  75.5
C)  -7.55 × 10-5
D)  7.55 × 10-5
E)  -1.32 × 10-2F) All of the above
G) A) and B)

Question 8

For the reaction C(s)  + H2O(g)  → CO(g)  + H2(g) 
ΔH° = 133.3 kJ/mol and ΔS° = 121.6 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)  823
E)  1096F) A) and E)
G) C) and D)

Question 9

Which one of the following processes produces a decrease in the entropy of the system?

Accepted Answer

A)  freezing of Fe(l) into Fe(s) 
B)  evaporation of liquid ethanol into gaseous ethanol
C)  dissolution of LiOH(s) in water
D)  melting ice to form water
E)  mixing of two gases into one containerF) A) and E)
G) B) and C)

Question 10

Which one of the following processes produces a decrease of the entropy of the system?

Accepted Answer

A)  dissolving sodium chloride in water
B)  sublimation of naphthalene
C)  dissolving oxygen in water
D)  boiling of alcohol
E)  explosion of nitroglycerineF) A) and C)
G) B) and C)

Question 11

Use the table below to answer the questions that follow.
Thermodynamic Quantities for Selected Substances at 298.15 K (25 °C) 
Substance ΔH°f (kJ/mol) ΔG°f (kJ/mol) S (J/K-mol) 
Carbon
C (s, diamond) 1.88 2.84 2.43
C (s, graphite) 0 0 5.69
C2H2 (g) 226.7 209.2 200.8
C2H4 (g) 52.30 68.11 219.4
C2H6 (g) -84.68 -32.89 229.5
CO (g) -110.5 -137.2 197.9
CO2 (g) -393.5 -394.4 213.6
Hydrogen
H2( g) 0 0 130.58
Oxygen
O2 (g) 0 0 205.0
H2O (l) -285.83 -237.13 69.91
-The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite)  + O2 (g)  → CO2(g) 
Is ________ J/K ∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

Accepted Answer

A)  +424.3
B)  +205.0
C)  -205.0
D)  -2.9
E)  +2.9F) All of the above
G) B) and D)

Question 12

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C2H4 (g)  + 3O2 (g)  → 2CO2 (g)  + 2H2O (l) 
The value of ΔS° for this reaction is ________ J/K ∙ mol.

Accepted Answer

A)  -267.4
B)  -140.9
C)  -347.6
D)  +347.6
E)  +140.9F) B) and D)
G) A) and D)

Question 13

For a given reaction, ΔH = +74.6 kJ/mol, and the reaction is spontaneous at temperatures above the crossover temperature, 449 K. The value of ΔS = ________ J/mol · K, assuming that ΔH and ΔS do not vary with temperature.

Accepted Answer

A)  166
B)  6020
C)  -166
D)  -6020
E)  3.35 × 104F) D) and E)
G) C) and E)

Question 14

The more negative ΔG° is for a given reaction, the larger the value of the corresponding equilibrium constant, K.

Accepted Answer

A) True 
 B)False

Question 15

A reversible process is one that ________.

Accepted Answer

A)  can be reversed with no net change in either system or surroundings
B)  happens spontaneously
C)  is spontaneous in both directions
D)  must be carried out at low temperature
E)  must be carried out at high temperatureF) C) and E)
G) B) and E)

Question 16

The value of ΔG° at 181.0 °C for the formation of calcium chloride from its constituent elements: Ca (s) + Cl2 (g)  → CaCl2 (s) 
Is ________ kJ/mol. At 25.0 °C for this reaction, ΔH° is -795.8 kJ/mol, ΔG° is -748.1 kJ/mol, and ΔS° is -159.8 J/K.

Accepted Answer

A)  -868.4
B)  -723.2
C)  7.18 × 104
D)  -766.9
E)  2.81 × 104F) C) and D)
G) A) and E)

Question 17

Calculate ΔG∘ (in kJ/mol)for the following reaction at 1 atm and 25 °C:
C2H6 (g)+ O2 (g)→ CO2 (g)+ H2O (l) (unbalanced)
ΔHf∘ C2H6 (g)= -84.7 kJ/mol; S∘ C2H6 (g)= 229.5 J/K ∙ mol;
ΔHf∘ CO2 (g)= -393.5 kJ/mol; S∘ CO2 (g)= 213.6 J/K ∙ mol;
ΔHf∘ H2O (l)= -285.8 kJ/mol; S∘ H2O (l)= 69.9 J/K ∙ mol;
S∘ O2 (g)= 205.0 J/K ∙ mol

Accepted Answer

Question 18

Consider the reaction: Ag+ (aq)  + Cl- (aq)  → AgCl (s) 
Given the following table of thermodynamic data at 298 K: + (aq)  + Cl- (aq)  → AgCl (s)  Given the following table of thermodynamic data at 298 K:   The value of K for the reaction at 25 °C is ________. A) 810 B) 5.3 × 109 C) 1.8 × 104 D) 3.7 × 1010 E) 1.9 × 10-10" class="answers-bank-image d-inline" rel="preload" > The value of K for the reaction at 25 °C is ________.

Accepted Answer

A)  810
B)  5.3 × 109
C)  1.8 × 104
D)  3.7 × 1010
E)  1.9 × 10-10F) A) and E)
G) D) and E)

Question 19

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) A) and C)
G) B) and D)

Question 20

Given the following table of thermodynamic data,   complete the following sentence. The vaporization of PCl3 (l) is ________. A) nonspontaneous at low temperature and spontaneous at high temperature B) spontaneous at low temperature and nonspontaneous at high temperature C) spontaneous at all temperatures D) nonspontaneous at all temperatures E) not enough information given to draw a conclusion" class="answers-bank-image d-inline" rel="preload" >   complete the following sentence. The vaporization of PCl3 (l) is ________.

Accepted Answer

A)  nonspontaneous at low temperature and spontaneous at high temperature
B)  spontaneous at low temperature and nonspontaneous at high temperature
C)  spontaneous at all temperatures
D)  nonspontaneous at all temperatures
E)  not enough information given to draw a conclusionF) C) and D)
G) A) and B)

Exam 19: Chemical Thermodynamics

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 Answer
verified

For a given reaction with ΔH = -28.1 kJ/mol, the ΔG = 0 at 372 K. The value of ΔS must be ________ J/K-mol, assuming that ΔH and ΔS do not vary with temperature.

Correct Answer
verified

The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements, CaCl₂(s) → Ca (s) + Cl₂ (g) Is ________ kJ/mol.

Correct Answer
verified

For the reaction 2 C₄H₁₀ (g) + 13 O₂ (g) → 8 CO₂ (g) + 10 H₂O (g) ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is ________.

Correct Answer
verified

Correct Answer
verified

The value of ΔG° at 181.0 °C for the formation of calcium chloride from its constituent elements: Ca (s) + Cl₂ (g) → CaCl₂ (s) Is ________ kJ/mol. At 25.0 °C for this reaction, ΔH° is -795.8 kJ/mol, ΔG° is -748.1 kJ/mol, and ΔS° is -159.8 J/K.

Correct Answer
verified

Which one of the following processes produces a decrease of the entropy of the system?

Correct Answer
verified

Correct Answer
verified

Given the following table of thermodynamic data, complete the following sentence. The vaporization of PCl₃ (l) is ________.

Correct Answer
verified

For a given reaction, ΔH = +74.6 kJ/mol, and the reaction is spontaneous at temperatures above the crossover temperature, 449 K. The value of ΔS = ________ J/mol · K, assuming that ΔH and ΔS do not vary with temperature.

Correct Answer
verified

ΔS is positive for the reaction ________.

Correct Answer
verified

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

Correct Answer
verified

Which one of the following processes produces a decrease in the entropy of the system?

Correct Answer
verified

Which of the following statements is true?

Correct Answer
verified

The more negative ΔG° is for a given reaction, the larger the value of the corresponding equilibrium constant, K.

Correct Answer
verified

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C₂H₄ (g) + 3O₂ (g) → 2CO₂ (g) + 2H₂O (l) The value of ΔS° for this reaction is ________ J/K ∙ mol.

Correct Answer
verified

For the reaction C(s) + H₂O(g) → CO(g) + H₂(g) ΔH° = 133.3 kJ/mol and ΔS° = 121.6 J/K ∙ mol at 298 K. At temperatures greater than ________ °C this reaction is spontaneous under standard conditions.

Correct Answer
verified

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO₂(g) → S (s, rhombic) + O₂(g) Is ________ J/K ∙ mol.

Correct Answer
verified

A reversible process is one that ________.

Correct Answer
verified

Consider the reaction: Ag⁺ (aq) + Cl^- (aq) → AgCl (s) Given the following table of thermodynamic data at 298 K: The value of K for the reaction at 25 °C is ________.

Correct Answer
verified

Exam 19: Chemical Thermodynamics

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

For a given reaction with ΔH = -28.1 kJ/mol, the ΔG = 0 at 372 K. The value of ΔS must be ________ J/K-mol, assuming that ΔH and ΔS do not vary with temperature.

Correct AnswerverifiedShow Answer

The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements, CaCl2 (s) → Ca (s) + Cl2 (g) Is ________ kJ/mol.

Correct AnswerverifiedShow Answer

For the reaction 2 C4H10 (g) + 13 O2 (g) → 8 CO2 (g) + 10 H2O (g) ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is ________.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The value of ΔG° at 181.0 °C for the formation of calcium chloride from its constituent elements: Ca (s) + Cl2 (g) → CaCl2 (s) Is ________ kJ/mol. At 25.0 °C for this reaction, ΔH° is -795.8 kJ/mol, ΔG° is -748.1 kJ/mol, and ΔS° is -159.8 J/K.

Correct AnswerverifiedShow Answer

Which one of the following processes produces a decrease of the entropy of the system?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Given the following table of thermodynamic data, complete the following sentence. The vaporization of PCl3 (l) is ________.

Correct AnswerverifiedShow Answer

For a given reaction, ΔH = +74.6 kJ/mol, and the reaction is spontaneous at temperatures above the crossover temperature, 449 K. The value of ΔS = ________ J/mol · K, assuming that ΔH and ΔS do not vary with temperature.

Correct AnswerverifiedShow Answer

ΔS is positive for the reaction ________.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which one of the following processes produces a decrease in the entropy of the system?

Correct AnswerverifiedShow Answer

Which of the following statements is true?

Correct AnswerverifiedShow Answer

The more negative ΔG° is for a given reaction, the larger the value of the corresponding equilibrium constant, K.

Correct AnswerverifiedShow Answer

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C2H4 (g) + 3O2 (g) → 2CO2 (g) + 2H2O (l) The value of ΔS° for this reaction is ________ J/K ∙ mol.

Correct AnswerverifiedShow Answer

For the reaction C(s) + H2O(g) → CO(g) + H2(g) ΔH° = 133.3 kJ/mol and ΔS° = 121.6 J/K ∙ mol at 298 K. At temperatures greater than ________ °C this reaction is spontaneous under standard conditions.

Correct AnswerverifiedShow Answer

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO2 (g) → S (s, rhombic) + O2 (g) Is ________ J/K ∙ mol.

Correct AnswerverifiedShow Answer

A reversible process is one that ________.

Correct AnswerverifiedShow Answer

Consider the reaction: Ag+ (aq) + Cl- (aq) → AgCl (s) Given the following table of thermodynamic data at 298 K: The value of K for the reaction at 25 °C is ________.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements, CaCl₂(s) → Ca (s) + Cl₂ (g) Is ________ kJ/mol.

Correct Answer
verified

For the reaction 2 C₄H₁₀ (g) + 13 O₂ (g) → 8 CO₂ (g) + 10 H₂O (g) ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is ________.

Correct Answer
verified

Correct Answer
verified

The value of ΔG° at 181.0 °C for the formation of calcium chloride from its constituent elements: Ca (s) + Cl₂ (g) → CaCl₂ (s) Is ________ kJ/mol. At 25.0 °C for this reaction, ΔH° is -795.8 kJ/mol, ΔG° is -748.1 kJ/mol, and ΔS° is -159.8 J/K.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Given the following table of thermodynamic data, complete the following sentence. The vaporization of PCl₃ (l) is ________.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C₂H₄ (g) + 3O₂ (g) → 2CO₂ (g) + 2H₂O (l) The value of ΔS° for this reaction is ________ J/K ∙ mol.

Correct Answer
verified

For the reaction C(s) + H₂O(g) → CO(g) + H₂(g) ΔH° = 133.3 kJ/mol and ΔS° = 121.6 J/K ∙ mol at 298 K. At temperatures greater than ________ °C this reaction is spontaneous under standard conditions.

Correct Answer
verified

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO₂(g) → S (s, rhombic) + O₂(g) Is ________ J/K ∙ mol.

Correct Answer
verified

Correct Answer
verified

Consider the reaction: Ag⁺ (aq) + Cl^- (aq) → AgCl (s) Given the following table of thermodynamic data at 298 K: The value of K for the reaction at 25 °C is ________.

Correct Answer
verified