Question 1

If a reaction is product-favored at any temperature, then DH$\circ$ is ____ and DS$\circ$is ____.

Accepted Answer

A)  positive; positive 
B)  positive; negative 
C)  zero; positive 
D)  negative; positive 
E)  negative; negative 
A)  positive; positive 
B)  positive; negative 
C)  zero; positive 
D)  negative; positive 
E)  negative; negative

Question 2

Consider the options given for the distribution of three units of energy to three particles. Which arrangement is least likely?

Accepted Answer

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

Question 3

Which statement is not correct?

Accepted Answer

A)  the aqueous hydrogen ion (H+) is the only species for which DH$\circ$f, S$\circ$, and DG$\circ$f each have a value of zero at 25$\circ$C 
B)  DH$\circ$f = 0 for each of the elements in its standard state at 25$\circ$C 
C)  DG$\circ$f = 0 for each of the elements in its standard state at 25$\circ$C 
D)  S$\circ$ ¹ 0 for each of the elements in its standard state at 25$\circ$C 
E)  DH$\circ$f, S$\circ$, and DG$\circ$f each have a value of zero for each of the elements in its standard state at 25$\circ$C 
A)  the aqueous hydrogen ion (H+) is the only species for which DH$\circ$f, S$\circ$, and DG$\circ$f each have a value of zero at 25$\circ$C 
B)  DH$\circ$f = 0 for each of the elements in its standard state at 25$\circ$C 
C)  DG$\circ$f = 0 for each of the elements in its standard state at 25$\circ$C 
D)  S$\circ$ ¹ 0 for each of the elements in its standard state at 25$\circ$C 
E)  DH$\circ$f, S$\circ$, and DG$\circ$f each have a value of zero for each of the elements in its standard state at 25$\circ$C

Question 4

Since no chemical process is 100% efficient, some Gibbs free energy is always "wasted" and converted to ____ instead of doing useful work.

Accepted Answer

A)  chemical energy 
B)  electricity 
C)  heat 
D)  light 
E)  mechanical energy 
A)  chemical energy 
B)  electricity 
C)  heat 
D)  light 
E)  mechanical energy

Question 5

Use the data given to calculate the value of DG$\circ$rxn at 25$\circ$C for the reaction given below. DG$\circ$f for CO(g) is -137.16 kJ/mol.

Accepted Answer

A)  -274.32 kJ 
B)  -137.16 kJ 
C)  -68.58 kJ 
D)  +137.16 kJ 
E)  +274.32 kJ 
A)  -274.32 kJ 
B)  -137.16 kJ 
C)  -68.58 kJ 
D)  +137.16 kJ 
E)  +274.32 kJ

Question 6

For a particular reaction, the value of DH$\circ$= +98.8 kJ and DS$\circ$ = +141.5 J/K. This reaction is

Accepted Answer

A)  product-favored, because DS$\circ$universe is positive 
B)  reactant-favored, because DS$\circ$universe is positive 
C)  reactant-favored, because DS$\circ$universe is negative 
D)  product-favored, because DS$\circ$universe is negative 
E)  cannot determine without further information 
A)  product-favored, because DS$\circ$universe is positive 
B)  reactant-favored, because DS$\circ$universe is positive 
C)  reactant-favored, because DS$\circ$universe is negative 
D)  product-favored, because DS$\circ$universe is negative 
E)  cannot determine without further information

Question 7

Compression of a gas is

Accepted Answer

A)  reactant-favored, since energy in the compressed gas is more dispersed. 
B)  reactant-favored, since matter in the compressed gas is more dispersed. 
C)  reactant-favored, since energy in the compressed gas is less dispersed. 
D)  product-favored, since energy in the compressed gas is less dispersed. 
E)  product-favored, since energy in the compressed gas is more dispersed. 
A)  reactant-favored, since energy in the compressed gas is more dispersed. 
B)  reactant-favored, since matter in the compressed gas is more dispersed. 
C)  reactant-favored, since energy in the compressed gas is less dispersed. 
D)  product-favored, since energy in the compressed gas is less dispersed. 
E)  product-favored, since energy in the compressed gas is more dispersed.

Question 8

Which statement is correct?

Accepted Answer

A)  The entropy of a pure substance is greater in the liquid state than in the gaseous state. 
B)  The entropy of a pure substance in a given state decreases as the temperature rises. 
C)  Because of the larger charges, the entropy of CaO(s) is greater than the entropy of KF(s). 
D)  Entropy decreases when ethanol, C2H5OH, dissolves in water. 
E)  A bottle of carbonated water has lower entropy than the same masses of carbon dioxide gas and distilled water. 
A)  The entropy of a pure substance is greater in the liquid state than in the gaseous state. 
B)  The entropy of a pure substance in a given state decreases as the temperature rises. 
C)  Because of the larger charges, the entropy of CaO(s) is greater than the entropy of KF(s). 
D)  Entropy decreases when ethanol, C2H5OH, dissolves in water. 
E)  A bottle of carbonated water has lower entropy than the same masses of carbon dioxide gas and distilled water.

Question 9

DS$\circ$ for a reaction can be calculated from the following equation.

Accepted Answer

A)  DS$\circ$ = (Smoles product) ×S$\circ$product - (Smoles reactant) ×S$\circ$reactant 
B)  DS$\circ$ = S(moles product × S$\circ$product) - S(moles reactant × S$\circ$reactant) 
C)  DS$\circ$ = S(moles reactant × S$\circ$reactant) - S(moles product × S$\circ$product) 
D)  DS$\circ$ = S(moles product × S$\circ$reactant) - S(moles reactant × S$\circ$product) 
E)  DS$\circ$= S(moles product × S$\circ$product) + S(moles reactant × S$\circ$reactant) 
A)  DS$\circ$ = (Smoles product) ×S$\circ$product - (Smoles reactant) ×S$\circ$reactant 
B)  DS$\circ$ = S(moles product × S$\circ$product) - S(moles reactant × S$\circ$reactant) 
C)  DS$\circ$ = S(moles reactant × S$\circ$reactant) - S(moles product × S$\circ$product) 
D)  DS$\circ$ = S(moles product × S$\circ$reactant) - S(moles reactant × S$\circ$product) 
E)  DS$\circ$= S(moles product × S$\circ$product) + S(moles reactant × S$\circ$reactant)

Question 10

A reaction is exothermic and has a negative value of DS$\circ$. The value of DG$\circ$ for this reaction is therefore:

Accepted Answer

A)  negative at all temperatures. 
B)  positive at all temperatures. 
C)  positive above 0$\circ$C and negative below 0$\circ$C. 
D)  positive above a certain temperature and negative below it. 
E)  negative above a certain temperature and positive below it. 
A)  negative at all temperatures. 
B)  positive at all temperatures. 
C)  positive above 0$\circ$C and negative below 0$\circ$C. 
D)  positive above a certain temperature and negative below it. 
E)  negative above a certain temperature and positive below it.

Question 11

At constant T and P, in which situation will the reaction be product-favored at high temperature but not at low temperature?

Accepted Answer

A) DH > 0 and DS 0 and DS > 0 C) DH 0 E) DH = 0 and DS < 0 A) DH > 0 and DS 0 and DS > 0 C) DH 0 E) DH = 0 and DS < 0

Question 12

Use the data given to calculate the value of K for the reaction at 5$\circ$C.

Accepted Answer

A)  1.9 × 1012 
B)  4.5 × 1010 
C)  5.7 × 109 
D)  1.3 × 106 
E)  1.0 
A)  1.9 × 1012 
B)  4.5 × 1010 
C)  5.7 × 109 
D)  1.3 × 106 
E)  1.0

Question 13

For a specific chemical reaction, the value of DG$\circ$ calculated from tabulated values of the standard Gibbs free energy of formation, DG$\circ$f, of the reactants and products is valid at

Accepted Answer

A)  all temperatures 
B)  standard temperature and pressure (STP) 
C)  0 K 
D)  273 K 
E)  the temperature specified for the tabulated values 
A)  all temperatures 
B)  standard temperature and pressure (STP) 
C)  0 K 
D)  273 K 
E)  the temperature specified for the tabulated values

Question 14

Five coins are tossed. Which combination of heads (H) and tails (T) is least likely?

Accepted Answer

A)  THTHT 
B)  TTTHT 
C)  HTTHT 
D)  HHTHT 
E)  THHTT 
A)  THTHT 
B)  TTTHT 
C)  HTTHT 
D)  HHTHT 
E)  THHTT

Question 15

Calculate the value of DS$\circ$ for the reaction shown:   At 25$\circ$C the values of entropy in J K-1 mol-1 are nitrogen, 191.61: hydrogen, 130.68; and ammonia, 192.77.

Accepted Answer

A)  -198.11 J/K 
B)  -259.03 J/K 
C)  -390.88 J/K 
D)  -393.20 J/K 
E)  -969.19 J/K 
A)  -198.11 J/K 
B)  -259.03 J/K 
C)  -390.88 J/K 
D)  -393.20 J/K 
E)  -969.19 J/K

Question 16

The value of DG$\circ$rxn at 45$\circ$C is -47.8 kJ. What is the value of the equilibrium constant for this reaction?

Accepted Answer

A)  1.14 
B)  1.02 
C)  1.05 × 1024 
D)  7.11 × 107 
E)  1.40 × 109 
A)  1.14 
B)  1.02 
C)  1.05 × 1024 
D)  7.11 × 107 
E)  1.40 × 109

Question 17

Two substances, A and B, have identical enthalpies of vaporization. They boil at 164$\circ$C and 236$\circ$C, respectively. If the entropy of vaporization of A is 87.2 J/K, what is the entropy of vaporization of B, in J/K?

Accepted Answer

A)  102 
B)  60.6 
C)  126 
D)  38.3 
E)  74.9 
A)  102 
B)  60.6 
C)  126 
D)  38.3 
E)  74.9

Question 18

How many of the following processes involve a decrease in disorder: humidifying dry air; distilling crude oil into gasoline, fuel oil, and jet fuel; filtering solid impurities out of a mixture; adding sand to water?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
E)  4 
A)  0 
B)  1 
C)  2 
D)  3 
E)  4

Question 19

At a particular temperature, a reactant-favored process is one in which

Accepted Answer

A)  reactants rapidly react with one another to form products 
B)  products rapidly react with one another to form reactants 
C)  products predominate over reactants 
D)  reactants predominate over products 
E)  large amounts of energy are produced 
A)  reactants rapidly react with one another to form products 
B)  products rapidly react with one another to form reactants 
C)  products predominate over reactants 
D)  reactants predominate over products 
E)  large amounts of energy are produced

Question 20

A reaction cannot change between being product-favored and being reactant-favored when

Accepted Answer

A) DH$\circ$rxn $\circ$rxn > 0 B) DH$\circ$rxn $\circ$rxn $\circ$rxn > 0 and DS$\circ$rxn $\circ$rxn > 0 and DS$\circ$rxn > 0 E) DH$\circ$rxn = 0 and DS$\circ$rxn < 0 A) DH$\circ$rxn $\circ$rxn > 0 B) DH$\circ$rxn $\circ$rxn $\circ$rxn > 0 and DS$\circ$rxn $\circ$rxn > 0 and DS$\circ$rxn > 0 E) DH$\circ$rxn = 0 and DS$\circ$rxn < 0

If a reaction is product-favored at any temperature, then DH^$\circ$ is and DS^$\circ$is .

Consider the options given for the distribution of three units of energy to three particles. Which arrangement is least likely?

Which statement is not correct?

Since no chemical process is 100% efficient, some Gibbs free energy is always "wasted" and converted to ____ instead of doing useful work.

For a particular reaction, the value of DH^$\circ$= +98.8 kJ and DS^$\circ$ = +141.5 J/K. This reaction is

Compression of a gas is

Which statement is correct?

DS^$\circ$ for a reaction can be calculated from the following equation.

A reaction is exothermic and has a negative value of DS^$\circ$. The value of DG^$\circ$ for this reaction is therefore:

At constant T and P, in which situation will the reaction be product-favored at high temperature but not at low temperature?

Use the data given to calculate the value of K for the reaction at 5^$\circ$C. $Use the data given to calculate the value of K for the reaction at 5<sup> \circ </sup>C.$ $Use the data given to calculate the value of K for the reaction at 5<sup> \circ </sup>C.$

For a specific chemical reaction, the value of DG^$\circ$ calculated from tabulated values of the standard Gibbs free energy of formation, DG^$\circ$_f, of the reactants and products is valid at

Five coins are tossed. Which combination of heads (H) and tails (T) is least likely?

The value of DG^$\circ$_rxn at 45^$\circ$C is -47.8 kJ. What is the value of the equilibrium constant for this reaction?

Two substances, A and B, have identical enthalpies of vaporization. They boil at 164^$\circ$C and 236^$\circ$C, respectively. If the entropy of vaporization of A is 87.2 J/K, what is the entropy of vaporization of B, in J/K?

How many of the following processes involve a decrease in disorder: humidifying dry air; distilling crude oil into gasoline, fuel oil, and jet fuel; filtering solid impurities out of a mixture; adding sand to water?

At a particular temperature, a reactant-favored process is one in which

A reaction cannot change between being product-favored and being reactant-favored when

The Nature of Chemistry

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Chemical Reactions

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Chemical Kinetics: Rates of Reactions

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Exam 17: Thermodynamics: Directionality of Chemical Reactions

If a reaction is product-favored at any temperature, then DH ∘\circ∘ is ____ and DS ∘\circ∘ is ____.

Consider the options given for the distribution of three units of energy to three particles. Which arrangement is least likely?

Which statement is not correct?

Since no chemical process is 100% efficient, some Gibbs free energy is always "wasted" and converted to ____ instead of doing useful work.

Use the data given to calculate the value of DG ∘\circ∘ rxn at 25 ∘\circ∘ C for the reaction given below. DG ∘\circ∘ f for CO(g) is -137.16 kJ/mol.

For a particular reaction, the value of DH ∘\circ∘ = +98.8 kJ and DS ∘\circ∘ = +141.5 J/K. This reaction is

Compression of a gas is

Which statement is correct?

DS ∘\circ∘ for a reaction can be calculated from the following equation.

A reaction is exothermic and has a negative value of DS ∘\circ∘ . The value of DG ∘\circ∘ for this reaction is therefore:

At constant T and P, in which situation will the reaction be product-favored at high temperature but not at low temperature?

Use the data given to calculate the value of K for the reaction at 5 ∘\circ∘ C.

For a specific chemical reaction, the value of DG ∘\circ∘ calculated from tabulated values of the standard Gibbs free energy of formation, DG ∘\circ∘ f, of the reactants and products is valid at

Five coins are tossed. Which combination of heads (H) and tails (T) is least likely?

Calculate the value of DS ∘\circ∘ for the reaction shown: At 25 ∘\circ∘ C the values of entropy in J K-1 mol-1 are nitrogen, 191.61: hydrogen, 130.68; and ammonia, 192.77.

The value of DG ∘\circ∘ rxn at 45 ∘\circ∘ C is -47.8 kJ. What is the value of the equilibrium constant for this reaction?

Two substances, A and B, have identical enthalpies of vaporization. They boil at 164 ∘\circ∘ C and 236 ∘\circ∘ C, respectively. If the entropy of vaporization of A is 87.2 J/K, what is the entropy of vaporization of B, in J/K?

How many of the following processes involve a decrease in disorder: humidifying dry air; distilling crude oil into gasoline, fuel oil, and jet fuel; filtering solid impurities out of a mixture; adding sand to water?

At a particular temperature, a reactant-favored process is one in which

A reaction cannot change between being product-favored and being reactant-favored when

The Nature of Chemistry

Atoms and Elements

Chemical Compounds

Quantities of Reactants and Products

Chemical Reactions

Energy and Chemical Reactions

Electron Configurations and the Periodic Table

Covalent Bonding

Molecular Structure

Gases and the Atmosphere

Liquids, Solids, and Materials

Chemical Kinetics: Rates of Reactions

Chemical Equilibrium

The Chemistry of Solutes and Solutions

Acids and Bases

Additional Aqueous Equilibria

Electrochemistry and Its Applications

Nuclear Chemistry

Filters

If a reaction is product-favored at any temperature, then DH^$\circ$ is and DS^$\circ$is .

For a particular reaction, the value of DH^$\circ$= +98.8 kJ and DS^$\circ$ = +141.5 J/K. This reaction is

DS^$\circ$ for a reaction can be calculated from the following equation.

A reaction is exothermic and has a negative value of DS^$\circ$. The value of DG^$\circ$ for this reaction is therefore:

Use the data given to calculate the value of K for the reaction at 5^$\circ$C. $Use the data given to calculate the value of K for the reaction at 5<sup> \circ </sup>C.$ $Use the data given to calculate the value of K for the reaction at 5<sup> \circ </sup>C.$

For a specific chemical reaction, the value of DG^$\circ$ calculated from tabulated values of the standard Gibbs free energy of formation, DG^$\circ$_f, of the reactants and products is valid at

The value of DG^$\circ$_rxn at 45^$\circ$C is -47.8 kJ. What is the value of the equilibrium constant for this reaction?

Two substances, A and B, have identical enthalpies of vaporization. They boil at 164^$\circ$C and 236^$\circ$C, respectively. If the entropy of vaporization of A is 87.2 J/K, what is the entropy of vaporization of B, in J/K?