Question 1

The value of ΔH° for the formation of phosphorous trichloride from its constituent elements, P2 (g)+ 3Cl2 (g)→ 2PCl3 (g)
Is ________ kJ/mol

Accepted Answer

A) -288.1 
B) +432.4 
C) -720.5 
D) +720.5 
E) -432.4 
A) -288.1 
B) +432.4 
C) -720.5 
D) +720.5 
E) -432.4

Question 2

The first law of thermodynamics can be given as ________.

Accepted Answer

A) ΔE = q + w 
B) Δ   =   -   
C) for any spontaneous process, the entropy of the universe increases 
D) the entropy of a pure crystalline substance at absolute zero is zero 
E) ΔS =   /T at constant temperature 
A) ΔE = q + w 
B) Δ   =   -   
C) for any spontaneous process, the entropy of the universe increases 
D) the entropy of a pure crystalline substance at absolute zero is zero 
E) ΔS =   /T at constant temperature

Question 3

The second law of thermodynamics states that ________.

Accepted Answer

A) ΔE = q + w 
B) ΔH°rxn = Σ nΔH°f (products)- Σ mΔH°f (reactants) 
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 temperature 
A) ΔE = q + w 
B) ΔH°rxn = Σ nΔH°f (products)- Σ mΔH°f (reactants) 
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 temperature

Question 4

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 information 
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 information

Question 5

A decrease in the entropy of the system is observed for the reaction ________.

Accepted Answer

A) 4 NH3 (g)+ 5 O2 (g)→ 4 NO (g)+ 6 H2O (g) 
B) 2 HgO (s)→ 2 Hg (l)+ O2 (g) 
C) UF6 (s)→ U (s)+ 3F2 (g) 
D) K (s)+ 1/2 I2 (g)→ KI (s) 
E) H2O (s)→ H2O (g) 
A) 4 NH3 (g)+ 5 O2 (g)→ 4 NO (g)+ 6 H2O (g) 
B) 2 HgO (s)→ 2 Hg (l)+ O2 (g) 
C) UF6 (s)→ U (s)+ 3F2 (g) 
D) K (s)+ 1/2 I2 (g)→ KI (s) 
E) H2O (s)→ H2O (g)

Question 6

The value of ΔG° at 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s,rhombic)+ O2(g)→ SO2 (g)
Is ________ kJ/mol.

Accepted Answer

A) +395.2 
B) +269.9 
C) -269.9 
D) +300.4 
E) -300.4 
A) +395.2 
B) +269.9 
C) -269.9 
D) +300.4 
E) -300.4

Question 7

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

Question 8

A reversible change produces the maximum amount of ________ that can be achieved by the system on the surroundings.

Accepted Answer

The answer of A reversible change produces the maximum amount...

Question 9

The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 
2S (s,rhombic)+ 3O2( g)→ 2SO3 (g)
Is ________ kJ/mol.

Accepted Answer

A) +790.4 
B) -790.4 
C) +395.2 
D) -395.2 
E) +105.1 
A) +790.4 
B) -790.4 
C) +395.2 
D) -395.2 
E) +105.1

Question 10

The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C2H6 (g)+ 7O2 (g)→ 4CO2 (g)+ 6H2O (l)
The value of ΔS° for this reaction is ________ J/K ∙ mol.

Accepted Answer

A) +718.0 
B) -620.1 
C) -718.0 
D) -151.0 
E) +151.0 
A) +718.0 
B) -620.1 
C) -718.0 
D) -151.0 
E) +151.0

Question 11

The entropy of the universe is ________.

Accepted Answer

A) constant 
B) continually decreasing 
C) continually increasing 
D) zero 
E) the same as the energy, E 
A) constant 
B) continually decreasing 
C) continually increasing 
D) zero 
E) the same as the energy, E

Question 12

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

Accepted Answer

A) -795.8 
B) +795.8 
C) +763.7 
D) +748.1 
E) -748.1 
A) -795.8 
B) +795.8 
C) +763.7 
D) +748.1 
E) -748.1

Question 13

The value of ΔS° for the formation of calcium chloride from its constituent elements, Ca (s)+ Cl2 (g)→ CaCl2 (s)
Is ________ J/K ∙ mol.

Accepted Answer

A) -104.6 
B) +104.6 
C) +369.0 
D) -159.8 
E) +159.8 
A) -104.6 
B) +104.6 
C) +369.0 
D) -159.8 
E) +159.8

Question 14

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C2H4 (g)+ H2(g)→ C2H6 (g)
Is ________ J/K ∙ mol.

Accepted Answer

A) -101.9 
B) -120.5 
C) -232.5 
D) +112.0 
E) +101.9 
A) -101.9 
B) -120.5 
C) -232.5 
D) +112.0 
E) +101.9

Question 15

At what temperature (in K)will a reaction become spontaneous?
 ΔH is 65.0 kJ/mol and ΔS is 149.00 J/K ∙ mol.

Accepted Answer

The answer of At what temperature (in K)will a reaction...

Question 16

What is the equilibrium constant for a reaction at 25 °C? ΔG° for the reaction is 2.8 kJ/mol.

Accepted Answer

A) 1.13 
B) 0.32 
C) -4.2 
D) -1.13 
E) More information is needed. 
A) 1.13 
B) 0.32 
C) -4.2 
D) -1.13 
E) More information is needed.

Question 17

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

Accepted Answer

A) S 
B) H 
C) q 
D) E 
E) T 
A) S 
B) H 
C) q 
D) E 
E) T

Question 18

The standard Gibbs free energy of formation of ________ is zero.
 (a) H2O (l)
(b)Fe (s)
(c)   (s)

Accepted Answer

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)

Question 19

The signs of ΔH° and ΔS° must be ________ and ________,respectively,for a reaction to be spontaneous at high temperatures but nonspontaneous at low temperatures.

Accepted Answer

A) +, - 
B) -, + 
C) -, - 
D) +, + 
E) +, 0 
A) +, - 
B) -, + 
C) -, - 
D) +, + 
E) +, 0

Question 20

The equilibrium position corresponds to which letter on the graph of G vs.f (course of reaction)below?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Exam 19: Chemical Thermodynamics

The value of ΔH° for the formation of phosphorous trichloride from its constituent elements, P2 (g)+ 3Cl2 (g)→ 2PCl3 (g) Is ________ kJ/mol

The first law of thermodynamics can be given as ________.

The second law of thermodynamics states that ________.

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 ________.

A decrease in the entropy of the system is observed for the reaction ________.

The value of ΔG° at 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s,rhombic)+ O2(g)→ SO2 (g) Is ________ kJ/mol.

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?

A reversible change produces the maximum amount of ________ that can be achieved by the system on the surroundings.

The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s,rhombic)+ 3O2( g)→ 2SO3 (g) Is ________ kJ/mol.

The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C2H6 (g)+ 7O2 (g)→ 4CO2 (g)+ 6H2O (l) The value of ΔS° for this reaction is ________ J/K ∙ mol.

The entropy of the universe is ________.

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

The value of ΔS° for the formation of calcium chloride from its constituent elements, Ca (s)+ Cl2 (g)→ CaCl2 (s) Is ________ J/K ∙ mol.

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C2H4 (g)+ H2(g)→ C2H6 (g) Is ________ J/K ∙ mol.

At what temperature (in K)will a reaction become spontaneous? ΔH is 65.0 kJ/mol and ΔS is 149.00 J/K ∙ mol.

What is the equilibrium constant for a reaction at 25 °C? ΔG° for the reaction is 2.8 kJ/mol.

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

The standard Gibbs free energy of formation of ________ is zero. (a) H2O (l) (b)Fe (s) (c) (s)

The signs of ΔH° and ΔS° must be ________ and ________,respectively,for a reaction to be spontaneous at high temperatures but nonspontaneous at low temperatures.

The equilibrium position corresponds to which letter on the graph of G vs.f (course of reaction)below?

Introduction: Matter, energy, and Measurement

Atoms, molecules, and Ions

Chemical Reactions and Reaction Stoichiometry

Reactions in Aqueous Solution

Thermochemistry

Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Gases

Liquids and Intermolecular Forces

Solids and Modern Materials

Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

Chemistry of the Environment

Electrochemistry

Nuclear Chemistry

Chemistry of the Nonmetals

Transition Metals and Coordination Chemistry

The Chemistry of Life: Organic and Biological Chemistry

Filters

The value of ΔH° for the formation of phosphorous trichloride from its constituent elements, P₂ (g)+ 3Cl₂ (g)→ 2PCl₃(g) Is ________ kJ/mol

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 ________.

The value of ΔG° at 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s,rhombic)+ O₂(g)→ SO₂ (g) Is ________ kJ/mol.

The value of ΔH° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s,rhombic)+ 3O₂( g)→ 2SO₃ (g) Is ________ kJ/mol.

The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C₂H₆ (g)+ 7O₂ (g)→ 4CO₂ (g)+ 6H₂O (l) The value of ΔS° for this reaction is ________ J/K ∙ mol.

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

The value of ΔS° for the formation of calcium chloride from its constituent elements, Ca (s)+ Cl₂ (g)→ CaCl₂(s) Is ________ J/K ∙ mol.

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C₂H₄(g)+ H₂(g)→ C₂H₆(g) Is ________ J/K ∙ mol.

The standard Gibbs free energy of formation of ________ is zero. (a) H₂O (l) (b)Fe (s) (c) (s)

The signs of ΔH° and ΔS° must be and ,respectively,for a reaction to be spontaneous at high temperatures but nonspontaneous at low temperatures.