Calculate ΔrG° for the reaction below at 25.0 °C. CH4(g) + H2O(g) → 3 H2(g) + CO(g) Given: ΔfG° [CH4(g)] = -50.8 kJ/mol, ΔfG° [H2O(g)] = -228.6 kJ/mol, ΔfG° [H2(g)] = 0.0 kJ/mol, and ΔfG° [CO(g)] = -137.2 kJ/mol.

A) -416.3 kJ/mol-rxn B) -142.2 kJ/mol-rxn C) +142.2 kJ/mol-rxn D) +315.0 kJ/mol-rxn E) +416.3 kJ/mol-rxn A) -416.3 kJ/mol-rxn B) -142.2 kJ/mol-rxn C) +142.2 kJ/mol-rxn D) +315.0 kJ/mol-rxn E) +416.3 kJ/mol-rxn

Hydrogen gas is prepared by electrolysis of water according to the reaction below. 2 H2O( $\ell$ ) ? 2 H2(g) + O2(g) Predict the signs of ?rH and ?rS.

A) ?rH > 0 and ?rS > 0 B) ?rH rS > 0 C) ?rH > 0 and ?rS rH rS rH = 0 and ?rS 0 and ?rS > 0 B) ?rH rS > 0 C) ?rH > 0 and ?rS rH rS rH = 0 and ?rS < 0

For the reaction Br2(l) → 2Br(g), _____.

A) ΔH is + and ΔS is + B) ΔH is + and ΔS = 0 C) ΔH is - and ΔS is - D) ΔH is - and ΔS is + E) ΔH is + and ΔS is - A) ΔH is + and ΔS is + B) ΔH is + and ΔS = 0 C) ΔH is - and ΔS is - D) ΔH is - and ΔS is + E) ΔH is + and ΔS is -

Calculate ΔG° at 298 K for the reaction below. I2(g) + Br2(g) → 2IBr(g) Given: ΔrH° = -11.6 kJ/mol-rxn; ΔrS° = 12 J/K⋅mol-rxn at 298 K.

A) -8.02 kJ/mol-rxn B) 15.2 kJ/mol-rxn C) -15.2 kJ/mol-rxn D) 3.59 × 103 kJ/mol-rxn E) -3.59 × 103 kJ/mol-rxn A) -8.02 kJ/mol-rxn B) 15.2 kJ/mol-rxn C) -15.2 kJ/mol-rxn D) 3.59 × 103 kJ/mol-rxn E) -3.59 × 103 kJ/mol-rxn

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K. NH4NO3(s) $\leftrightharpoons$ NH4NO3(aq) Which of the following is the equilibrium constant for the reaction? (R = 8.314 J/K?mol)

A) 1.9 × 10-3 B) 6.6 × 10-2 C) 1.0 D) 15 E) 5.2 × 102 A) 1.9 × 10-3 B) 6.6 × 10-2 C) 1.0 D) 15 E) 5.2 × 102

Using the given data, determine ?rG° at 500.0 K for the reaction below. Ba(s) + H2O(g) ? BaO(s) + H2(g) \[\begin{array} { l l l } \underline { \text { Substance } } & \Delta _ { f } \underline { H ^ { \circ } ( \mathrm { kJ } / \text { mol-rxn } ) \text { at } 298 \mathrm {~K} } &{ S ^ { \circ } ( \mathrm { J } / \mathrm { K } \cdot \text { mol-rxn } ) \text { at } 298 \mathrm {~K} } \\ \hline \mathrm{Ba}(s) & 0 & 62.8 \\ \mathrm{H}_{2} \mathrm{O}(g) & -241.8 & 188.7 \\ \mathrm{BaO}(s) & -592 & 70.4 \\ \mathrm{H}_{2}(g) & 0 & 130.6 \end{array}\]

A) 325.0 kJ/mol-rxn B) -325.0 kJ/mol-rxn C) 335.2 kJ/mol-rxn D) -335.2 kJ/mol-rxn E) -375.5 kJ/mol-rxn A) 325.0 kJ/mol-rxn B) -325.0 kJ/mol-rxn C) 335.2 kJ/mol-rxn D) -335.2 kJ/mol-rxn E) -375.5 kJ/mol-rxn

Exam 19: Principles of Chemical Reactivity: Entropy and Free Energy

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Which of the following is correct for the condensation of gaseous oxygen at -188 °C? (The normal boiling point of oxygen is -183 °C.)

(Multiple Choice)

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Question 21

Calculate Δ_rG° for the reaction below at 25.0 °C. CH₄(g) + H₂O(g) → 3 H₂(g) + CO(g) Given: Δ_fG° [CH₄(g)] = -50.8 kJ/mol, Δ_fG° [H₂O(g)] = -228.6 kJ/mol, Δ_fG° [H₂(g)] = 0.0 kJ/mol, and Δ_fG° [CO(g)] = -137.2 kJ/mol.

(Multiple Choice)

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Question 22

For any process, the change in entropy of the universe equals the sum of the entropy changes for the system and for the ________.

(Short Answer)

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Question 23

Hydrogen gas is prepared by electrolysis of water according to the reaction below. 2 H₂O( $\ell$ ) ? 2 H₂(g) + O₂(g) Predict the signs of ?_rH and ?_rS.

(Multiple Choice)

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Question 24

The standard free energy change for a chemical reaction is +13.3 kJ/mol. Which of the following is the equilibrium constant for the reaction at 125 °C? (R = 8.314 J/K⋅mol)

(Multiple Choice)

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Question 25

ΔG° = 0 for a reaction indicates that _____.

(Multiple Choice)

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Question 26

For the reaction Br₂(l) → 2Br(g), _____.

(Multiple Choice)

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Question 27

If a chemical reaction occurs in a direction that has a positive change in entropy, then _____.

(Multiple Choice)

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Question 28

Calculate the enthalpy of vaporization of water at its normal boiling point. ΔS° [H₂O( $\ell$ )] = 69.9 J/K⋅mol and ΔS° [H₂O(g)] = 188.8 J/K⋅mol.

(Short Answer)

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Question 29

Calculate ΔS°(universe) for the combustion of acetylene at 298.15 K using the reaction below. (Given: ΔS°(system) = -194.6 J/K and ΔH°(system) = -2511.2 kJ) 2 C₂H₂(g) + 5 O₂(g) → 4 CO₂(g) + 2 H₂O(g)

(Multiple Choice)

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Question 30

A change of state occurring in a system is accompanied by 60.7 kJ of heat that is transferred to the surroundings at a constant pressure and at a constant temperature of 300 K. Calculate the ΔS(surroundings) for the process.

(Multiple Choice)

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Question 31

In which of the following reactions is Δ_rS° expected to be positive?

(Multiple Choice)

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Question 32

A reaction is said to be under thermodynamic control when _____.

(Multiple Choice)

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Question 33

Calculate ΔG° at 298 K for the reaction below. I₂(g) + Br₂(g) → 2IBr(g) Given: Δ_rH° = -11.6 kJ/mol-rxn; Δ_rS° = 12 J/K⋅mol-rxn at 298 K.

(Multiple Choice)

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Question 34

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K. NH₄NO₃(s) $\leftrightharpoons$ NH₄NO₃(aq) Which of the following is the equilibrium constant for the reaction? (R = 8.314 J/K?mol)

(Multiple Choice)

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Question 35

For a chemical reaction, if Δ_rG° = 0, then _____.

(Multiple Choice)

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Question 36

Which of the following is true of a reaction that is product-favored?

(Multiple Choice)

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Question 37

Determine ?_fG° at 298 K for SnO using the data below. Sn(s) + SnO₂(s) ? 2SnO(s) Given: $\Delta _ { \mathrm { r } } G ^ { \circ } = 12.0 \mathrm {~kJ} / \mathrm { mol } - \mathrm { rxn }$ at $298 \mathrm {~K}$ Substance $\quad \Delta f G ^ { \circ } ( \mathrm { kJ } / \mathrm { mol } )$ at $298 \mathrm {~K}$ $\mathrm { SnO } ( s ) \quad\quad\quad ?$ $\mathrm { SnO } _ { 2 } ( s ) \quad - 515.8$

(Multiple Choice)

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Question 38

For a chemical system, Δ_rG° and Δ_rG are equal when:

(Multiple Choice)

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Question 39

Using the given data, determine ?rG° at 500.0 K for the reaction below. Ba(s) + H₂O(g) ? BaO(s) + H₂(g) (/\cdot mol-rxn ) at 298 (s) 0 62.8 (g) -241.8 188.7 (s) -592 70.4 (g) 0 130.6

(Multiple Choice)

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Question 40

Showing 21 - 40 of 70

Exam 19: Principles of Chemical Reactivity: Entropy and Free Energy

Which of the following is correct for the condensation of gaseous oxygen at -188 °C? (The normal boiling point of oxygen is -183 °C.)

Calculate ΔrG° for the reaction below at 25.0 °C. CH4(g) + H2O(g) → 3 H2(g) + CO(g) Given: ΔfG° [CH4(g)] = -50.8 kJ/mol, ΔfG° [H2O(g)] = -228.6 kJ/mol, ΔfG° [H2(g)] = 0.0 kJ/mol, and ΔfG° [CO(g)] = -137.2 kJ/mol.

For any process, the change in entropy of the universe equals the sum of the entropy changes for the system and for the ________.

Hydrogen gas is prepared by electrolysis of water according to the reaction below. 2 H2O( ℓ\ellℓ ) ? 2 H2(g) + O2(g) Predict the signs of ?rH and ?rS.

The standard free energy change for a chemical reaction is +13.3 kJ/mol. Which of the following is the equilibrium constant for the reaction at 125 °C? (R = 8.314 J/K⋅mol)

ΔG° = 0 for a reaction indicates that _____.

For the reaction Br2(l) → 2Br(g), _____.

If a chemical reaction occurs in a direction that has a positive change in entropy, then _____.

Calculate the enthalpy of vaporization of water at its normal boiling point. ΔS° [H2O( ℓ\ellℓ )] = 69.9 J/K⋅mol and ΔS° [H2O(g)] = 188.8 J/K⋅mol.

Calculate ΔS°(universe) for the combustion of acetylene at 298.15 K using the reaction below. (Given: ΔS°(system) = -194.6 J/K and ΔH°(system) = -2511.2 kJ) 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g)

A change of state occurring in a system is accompanied by 60.7 kJ of heat that is transferred to the surroundings at a constant pressure and at a constant temperature of 300 K. Calculate the ΔS(surroundings) for the process.

In which of the following reactions is ΔrS° expected to be positive?

A reaction is said to be under thermodynamic control when _____.

Calculate ΔG° at 298 K for the reaction below. I2(g) + Br2(g) → 2IBr(g) Given: ΔrH° = -11.6 kJ/mol-rxn; ΔrS° = 12 J/K⋅mol-rxn at 298 K.

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K. NH4NO3(s) ⇋\leftrightharpoons⇋ NH4NO3(aq) Which of the following is the equilibrium constant for the reaction? (R = 8.314 J/K?mol)

For a chemical reaction, if ΔrG° = 0, then _____.

Which of the following is true of a reaction that is product-favored?

For a chemical system, ΔrG° and ΔrG are equal when:

Using the given data, determine ?rG° at 500.0 K for the reaction below. Ba(s) + H2O(g) ? BaO(s) + H2(g) (/\cdot mol-rxn ) at 298 (s) 0 62.8 (g) -241.8 188.7 (s) -592 70.4 (g) 0 130.6

Basic Concepts of Chemistry

Lets Review: the Tools of Quantitative Chemistry

Atoms, Molecules, and Ions

Chemical Reactions

Stoichiometry: Quantitative Information About Chemical Reactions

Principles of Chemical Reactivity: Energy and Chemical Reactions

The Structure of Atoms

The Structure of Atoms and Periodic Trends

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Bonding and Molecular Structure Orbital Hybridization and Molecular Orbitals

Gases and Their Properties

Intermolecular Forces and Liquids

The Solid State

Solutions and Their Behavior

Chemical Kinetics: the Rates of Chemical Reactions

Principles of Chemical Reactivity: Equilibria

Principles of Chemical Reactivity: the Chemistry of Acids and Bases

Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

Principles of Chemical Reactivity: Electron Transfer Reactions

Environmental Chemistry: Earths Environment, Energy, and Sustainability

The Chemistry of the Main Group Elements

The Chemistry of the Transition Elements

Carbon: Not Just Another Element

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Calculate Δ_rG° for the reaction below at 25.0 °C. CH₄(g) + H₂O(g) → 3 H₂(g) + CO(g) Given: Δ_fG° [CH₄(g)] = -50.8 kJ/mol, Δ_fG° [H₂O(g)] = -228.6 kJ/mol, Δ_fG° [H₂(g)] = 0.0 kJ/mol, and Δ_fG° [CO(g)] = -137.2 kJ/mol.

Hydrogen gas is prepared by electrolysis of water according to the reaction below. 2 H₂O( $\ell$ ) ? 2 H₂(g) + O₂(g) Predict the signs of ?_rH and ?_rS.

For the reaction Br₂(l) → 2Br(g), _____.

Calculate the enthalpy of vaporization of water at its normal boiling point. ΔS° [H₂O( $\ell$ )] = 69.9 J/K⋅mol and ΔS° [H₂O(g)] = 188.8 J/K⋅mol.

Calculate ΔS°(universe) for the combustion of acetylene at 298.15 K using the reaction below. (Given: ΔS°(system) = -194.6 J/K and ΔH°(system) = -2511.2 kJ) 2 C₂H₂(g) + 5 O₂(g) → 4 CO₂(g) + 2 H₂O(g)

In which of the following reactions is Δ_rS° expected to be positive?

Calculate ΔG° at 298 K for the reaction below. I₂(g) + Br₂(g) → 2IBr(g) Given: Δ_rH° = -11.6 kJ/mol-rxn; Δ_rS° = 12 J/K⋅mol-rxn at 298 K.

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K. NH₄NO₃(s) $\leftrightharpoons$ NH₄NO₃(aq) Which of the following is the equilibrium constant for the reaction? (R = 8.314 J/K?mol)

For a chemical reaction, if Δ_rG° = 0, then _____.

For a chemical system, Δ_rG° and Δ_rG are equal when:

Using the given data, determine ?rG° at 500.0 K for the reaction below. Ba(s) + H₂O(g) ? BaO(s) + H₂(g) (/\cdot mol-rxn ) at 298 (s) 0 62.8 (g) -241.8 188.7 (s) -592 70.4 (g) 0 130.6