Question 1

For a chemical reaction to be spontaneous at all temperatures, which of the following conditions must be met?

Accepted Answer

A)  .F1F1F1S1F1F1F10S° > 0, F1F1F1S1F1F1F10H° > 0 
B)  .F1F1F1S1F1F1F10S° > 0, F1F1F1S1F1F1F10H°  0 
E)  It is not possible for a reaction to be spontaneous at all temperatures. 
A)  .F1F1F1S1F1F1F10S° > 0, F1F1F1S1F1F1F10H° > 0 
B)  .F1F1F1S1F1F1F10S° > 0, F1F1F1S1F1F1F10H°  0 
E)  It is not possible for a reaction to be spontaneous at all temperatures.

Question 2

For a reaction at equilibrium, F1F1F1S1F1F1F10Suniv = 0.

Accepted Answer

A) True 
 B)False

Question 3

Which of the following is true for a system at equilibrium?

Accepted Answer

A)  .F1F1F1S1F1F1F10S°sys = F1F1F1S1F1F1F10S°surr 
B)  .F1F1F1S1F1F1F10S°sys = -F1F1F1S1F1F1F10S°surr 
C)  .F1F1F1S1F1F1F10S°sys = F1F1F1S1F1F1F10S°surr = 0 
D)  .F1F1F1S1F1F1F10S°univ > 0 
E)  None of the above is a sufficient condition. 
A)  .F1F1F1S1F1F1F10S°sys = F1F1F1S1F1F1F10S°surr 
B)  .F1F1F1S1F1F1F10S°sys = -F1F1F1S1F1F1F10S°surr 
C)  .F1F1F1S1F1F1F10S°sys = F1F1F1S1F1F1F10S°surr = 0 
D)  .F1F1F1S1F1F1F10S°univ > 0 
E)  None of the above is a sufficient condition.

Question 4

As a chemical reaction proceeds toward equilibrium, the free energy of the system decreases.

Accepted Answer

A) True 
 B)False

Question 5

Given: C2H2(g) F1F1F1S1F1F1F10 2C(graphite) + H2(g) F1F1F1S1F1F1F10G° = -209 kJ
A sample of gaseous C2H2 (acetylene, or ethyne) was stored for one year, yet at the end of this period the sample remained unchanged and no graphite or hydrogen gas had been formed. Briefly explain why there is no inconsistency between the sign of F1F1F1S1F1F1F10G° and the apparent stability of the sample.

Accepted Answer

Relative to graphite and hydrogen, acety

Question 6

Nitric oxide reacts with chlorine to form NOCl. The data refer to 298 K.   What is the value of F1F1F1S1F1F1F10G° for this reaction at 550 K?

Accepted Answer

A)  -143.76 kJ 
B)  -78.78 kJ 
C)  -22.24 kJ 
D)  -10.56 kJ 
E)  66600 kJ 
A)  -143.76 kJ 
B)  -78.78 kJ 
C)  -22.24 kJ 
D)  -10.56 kJ 
E)  66600 kJ

Question 7

A reaction has a positive value of F1F1F1S1F1F1F10H° and a positive value of F1F1F1S1F1F1F10S°.
Draw a neat, labeled schematic plot to show how F1F1F1S1F1F1F10G° (y-axis) will depend on absolute temperature (x-axis).

Accepted Answer

The answer of A reaction has a positive value of...

Question 8

Calculate F1F1F1S1F1F1F10S° for the combustion of propane.

Accepted Answer

A)  -100.9 J/K 
B)  -72.5 J/K 
C)  72.5 J/K 
D)  100.9 J/K 
E)  877.5 J/K 
A)  -100.9 J/K 
B)  -72.5 J/K 
C)  72.5 J/K 
D)  100.9 J/K 
E)  877.5 J/K

Question 9

Which relationship or statement best describes F1F1F1S1F1F1F10S° for the following reaction? 
KCl(s) F1F1F1S1F1F1F10 K+(aq) + Cl-(aq)

Accepted Answer

A)  .F1F1F1S1F1F1F10S° F1F1F1S1F1F1F10 0 
B)  .F1F1F1S1F1F1F10S°  0 
D)  .F1F1F1S1F1F1F10S° = F1F1F1S1F1F1F10H°/T 
E)  More information is needed to make a reasonable prediction. 
A)  .F1F1F1S1F1F1F10S° F1F1F1S1F1F1F10 0 
B)  .F1F1F1S1F1F1F10S°  0 
D)  .F1F1F1S1F1F1F10S° = F1F1F1S1F1F1F10H°/T 
E)  More information is needed to make a reasonable prediction.

Question 10

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

Accepted Answer

A) q sys > 0, F1F1F1S1F1F1F10Ssurr sys surr > 0 C) q sys surr sys > 0, F1F1F1S1F1F1F10Ssurr > 0 E) w < 0 A) q sys > 0, F1F1F1S1F1F1F10Ssurr sys surr > 0 C) q sys surr sys > 0, F1F1F1S1F1F1F10Ssurr > 0 E) w < 0

Question 11

Which of the following should have the greatest molar entropy at 298 K?

Accepted Answer

A)  CH4(g) 
B)  H2O(l) 
C)  NaCl(s) 
D)  N2O4(g) 
E)  H2(g) 
A)  CH4(g) 
B)  H2O(l) 
C)  NaCl(s) 
D)  N2O4(g) 
E)  H2(g)

Question 12

Which of the following values is based on the Third Law of Thermodynamics?

Accepted Answer

A)  .F1F1F1S1F1F1F10H° f = 0 for Al(s) at 298 K 
B)  .F1F1F1S1F1F1F10G° f = 0 for H2(g) at 298 K 
C)  S° = 51.446 J/(mol·K) for Na(s) at 298 K 
D)  q sys 2O(l) F1F1F1S1F1F1F10 H2O(s) at 0°C 
E)  none of the above 
A)  .F1F1F1S1F1F1F10H° f = 0 for Al(s) at 298 K 
B)  .F1F1F1S1F1F1F10G° f = 0 for H2(g) at 298 K 
C)  S° = 51.446 J/(mol·K) for Na(s) at 298 K 
D)  q sys 2O(l) F1F1F1S1F1F1F10 H2O(s) at 0°C 
E)  none of the above

Question 13

Which, if any, of the following processes is spontaneous under the specified conditions?

Accepted Answer

A)  H2O(l) F1F1F1S1F1F1F10 H2O(s) at 25°C 
B)  CO2(s) F1F1F1S1F1F1F10 CO2(g) at 0°C 
C)  2H2O(g) F1F1F1S1F1F1F10 2H2(g) + O2(g) 
D)  C(graphite) F1F1F1S1F1F1F10 C(diamond) at 25°C and 1 atm pressure 
E)  None of the above is spontaneous. 
A)  H2O(l) F1F1F1S1F1F1F10 H2O(s) at 25°C 
B)  CO2(s) F1F1F1S1F1F1F10 CO2(g) at 0°C 
C)  2H2O(g) F1F1F1S1F1F1F10 2H2(g) + O2(g) 
D)  C(graphite) F1F1F1S1F1F1F10 C(diamond) at 25°C and 1 atm pressure 
E)  None of the above is spontaneous.

Question 14

You are given pure samples of ammonia, NH3(g), and nitrogen trifluoride, NF3(g). What prediction would you make concerning their standard molar entropies at 298 K?

Accepted Answer

A)  S°ammonia > S°nitrogen trifluoride 
B)  S°ammonia nitrogen trifluoride 
C)  S°ammonia F1F1F1S1F1F1F10 S°nitrogen trifluoride 
D)  Other conditions need to be specified before a reliable prediction can be made. 
E)  Even if more conditions are specified, a reliable prediction cannot be made. 
A)  S°ammonia > S°nitrogen trifluoride 
B)  S°ammonia nitrogen trifluoride 
C)  S°ammonia F1F1F1S1F1F1F10 S°nitrogen trifluoride 
D)  Other conditions need to be specified before a reliable prediction can be made. 
E)  Even if more conditions are specified, a reliable prediction cannot be made.

For a chemical reaction to be spontaneous at all temperatures, which of the following conditions must be met?

For a reaction at equilibrium, S_univ = 0.

Which of the following is true for a system at equilibrium?

As a chemical reaction proceeds toward equilibrium, the free energy of the system decreases.

Nitric oxide reacts with chlorine to form NOCl. The data refer to 298 K. What is the value of G° for this reaction at 550 K?

A reaction has a positive value of H° and a positive value of S°. Draw a neat, labeled schematic plot to show how G° (y-axis) will depend on absolute temperature (x-axis).

Calculate S° for the combustion of propane.

Which relationship or statement best describes S° for the following reaction? KCl(s)  K⁺(aq) + Cl^-(aq)

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

Which of the following should have the greatest molar entropy at 298 K?

Which of the following values is based on the Third Law of Thermodynamics?

Which, if any, of the following processes is spontaneous under the specified conditions?

You are given pure samples of ammonia, NH₃(g), and nitrogen trifluoride, NF₃(g). What prediction would you make concerning their standard molar entropies at 298 K?

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

The 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: Bonding, Structure, and Reactivity

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

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Exam 20: Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

For a chemical reaction to be spontaneous at all temperatures, which of the following conditions must be met?

For a reaction at equilibrium, Suniv = 0.

Which of the following is true for a system at equilibrium?

As a chemical reaction proceeds toward equilibrium, the free energy of the system decreases.

Nitric oxide reacts with chlorine to form NOCl. The data refer to 298 K. What is the value of G° for this reaction at 550 K?

A reaction has a positive value of H° and a positive value of S°. Draw a neat, labeled schematic plot to show how G° (y-axis) will depend on absolute temperature (x-axis).

Calculate S° for the combustion of propane.

Which relationship or statement best describes S° for the following reaction? KCl(s)  K+(aq) + Cl-(aq)

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

Which of the following should have the greatest molar entropy at 298 K?

Which of the following values is based on the Third Law of Thermodynamics?

Which, if any, of the following processes is spontaneous under the specified conditions?

You are given pure samples of ammonia, NH3(g), and nitrogen trifluoride, NF3(g). What prediction would you make concerning their standard molar entropies at 298 K?

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

The 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: Bonding, Structure, and Reactivity

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

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

For a reaction at equilibrium, S_univ = 0.

Which relationship or statement best describes S° for the following reaction? KCl(s)  K⁺(aq) + Cl^-(aq)

You are given pure samples of ammonia, NH₃(g), and nitrogen trifluoride, NF₃(g). What prediction would you make concerning their standard molar entropies at 298 K?