Question 1

Which of the following is always true for an endothermic process?

Accepted Answer

A) q sys > 0, Δ S surr sys surr > 0 C) q sys surr sys > 0, Δ S surr > 0 E) w < 0 A) q sys > 0, Δ S surr sys surr > 0 C) q sys surr sys > 0, Δ S surr > 0 E) w < 0

Question 2

You are given pure samples of pentane, CH3CH2CH2CH2CH3(l), and 1,3-pentadiene, CH2=CHCH=CHCH3(l). What prediction would you make concerning their standard molar entropies at 298 K?

Accepted Answer

A) S° pentane > S° 1, 3-pentadiene 
B) S° pentane 1, 3-pentadiene 
C) S° pentane ≈ S° 1, 3-pentadiene 
D) S° pentane = S° 1, 3-pentadiene + 2 S°H 2 
E) More information is needed to make reasonable predictions. 
A) S° pentane > S° 1, 3-pentadiene 
B) S° pentane 1, 3-pentadiene 
C) S° pentane ≈ S° 1, 3-pentadiene 
D) S° pentane = S° 1, 3-pentadiene + 2 S°H 2 
E) More information is needed to make reasonable predictions.

Question 3

Which one of the following changes of state increases the entropy of the system?

Accepted Answer

A) Condensation 
B) Cooling a gas 
C) Freezing 
D) Crystallization 
E) Sublimation 
A) Condensation 
B) Cooling a gas 
C) Freezing 
D) Crystallization 
E) Sublimation

Question 4

Calculate ΔG° for the reaction SiCl4(g) + 2Mg(s) → 2MgCl2(s) + Si(s)

Accepted Answer

A) 566.60 kJ 
B) 50.38 kJ 
C) 25.19 kJ 
D) −25.19 kJ 
E) −566.60 kJ 
A) 566.60 kJ 
B) 50.38 kJ 
C) 25.19 kJ 
D) −25.19 kJ 
E) −566.60 kJ

Question 5

Iron(III) oxide can be reduced by carbon monoxide. Fe2O3(s) + 3CO(g) ⇄ 2Fe(s) + 3CO2(g)
Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Accepted Answer

A) 7.0 × 10 −6 
B) 1.3 × 10 −3 
C) 2.2 × 10 4 
D) 1.4 × 10 5 
E) > 2.0 × 10 5 
A) 7.0 × 10 −6 
B) 1.3 × 10 −3 
C) 2.2 × 10 4 
D) 1.4 × 10 5 
E) > 2.0 × 10 5

Which of the following is always true for an endothermic process?

You are given pure samples of pentane, CH₃CH₂CH₂CH₂CH₃(l), and 1,3-pentadiene, CH₂=CHCH=CHCH₃(l). What prediction would you make concerning their standard molar entropies at 298 K?

Which one of the following changes of state increases the entropy of the system?

Calculate ΔG° for the reaction SiCl₄(g) + 2Mg(s) → 2MgCl₂(s) + Si(s)

Iron(III) oxide can be reduced by carbon monoxide. Fe₂O₃(s) + 3CO(g) ⇄ 2Fe(s) + 3CO₂(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Keys to the Study of Chemistry: Definitions, Units, and Problem Solving

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Exam 20: Thermodynamics: Entropy, Free Energy, and Reaction Direction

Which of the following is always true for an endothermic process?

You are given pure samples of pentane, CH3CH2CH2CH2CH3(l), and 1,3-pentadiene, CH2=CHCH=CHCH3(l). What prediction would you make concerning their standard molar entropies at 298 K?

Which one of the following changes of state increases the entropy of the system?

Calculate ΔG° for the reaction SiCl4(g) + 2Mg(s) → 2MgCl2(s) + Si(s)

Iron(III) oxide can be reduced by carbon monoxide. Fe2O3(s) + 3CO(g) ⇄ 2Fe(s) + 3CO2(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Keys to the Study of Chemistry: Definitions, Units, and Problem Solving

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

You are given pure samples of pentane, CH₃CH₂CH₂CH₂CH₃(l), and 1,3-pentadiene, CH₂=CHCH=CHCH₃(l). What prediction would you make concerning their standard molar entropies at 298 K?

Calculate ΔG° for the reaction SiCl₄(g) + 2Mg(s) → 2MgCl₂(s) + Si(s)

Iron(III) oxide can be reduced by carbon monoxide. Fe₂O₃(s) + 3CO(g) ⇄ 2Fe(s) + 3CO₂(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.