Question 1

Given the following equation, N₂O(g) + NO₂(g) → 3NO(g) Δ_rG° = -23.0 kJ mol^-1 Calculate Δ_rG° for the following reaction: 3N₂O(g) + 3NO₂(g) → 9NO(g)

Accepted Answer

The given equation has a Δ_rG° of -23.0 kJ mol^-1, and the new equation has three times the amount of reactants and products. According to the equation Δ_rG° = Σ_rG°(products) - Σ_rG°(reactants), the entropy change will also be tripled for the new equation. Therefore, Δ_rG° for the new equation is -23.0 kJ mol^-1 x 3 = -69.0 kJ mol^-1.

Question 2

What is the change in Gibbs energy of a process?

Accepted Answer

The change in Gibbs energy of a process is the maximum amount of energy available to do work. It is a measure of the spontaneity and feasibility of a chemical or physical process. A negative change in Gibbs energy indicates that the process is spontaneous and can do work, while a positive change in Gibbs energy indicates that the process is not spontaneous and requires energy input to occur.

Question 3

Identify the compound with the highest standard Gibbs energy of formation.

Accepted Answer

O₃(g) has the highest standard Gibbs energy of formation because it is a highly unstable compound.

Question 4

Given the following equation, N₂O(g) + NO₂(g) → 3NO(g) Δ_rG°= -23.0 kJ mol^-1 Calculate Δ_rG^o for the following reaction: 3NO(g) → N₂O(g) + NO₂(g)

Accepted Answer

The reverse reaction has the opposite sign for ΔrG°. Therefore, ΔrG° for 3NO(g) → N2O(g) + NO2(g) is +23.0 kJ mol^-1.

Question 5

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) S°(J K^-1 mol^-1) 192.8 205.2 210.8 188.8

Accepted Answer

The answer of Calculate Δ_rS° for the following reaction. The...

Question 6

Identify the compound with the standard Gibbs energy of formation equal to zero.

Accepted Answer

The standard Gibbs energy of formation, ΔG°f, represents the change in Gibbs energy when one mole of a compound is formed from its constituent elements in their standard states. If ΔG°f is zero, it means that the compound can be formed from its constituent elements without any input of energy. Therefore, the compound is most stable under standard conditions. In this case, the only compound with a standard Gibbs energy of formation equal to zero is N₂(g).

Question 7

What is the name of the reaction that achieves the theoretical limits with respect to the change in Gibbs energy in thermodynamics?

Accepted Answer

A reversible reaction is the only type of reaction that achieves the theoretical limits with respect to the change in Gibbs energy in thermodynamics. In a reversible reaction, the forward and reverse reactions occur at equal rates, resulting in no net change in the system. This allows the system to approach the thermodynamic limit, where the change in Gibbs energy approaches zero.

Question 8

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Accepted Answer

The answer of Which one of the following has the...

Question 9

Calculate Δ_rS° for the following reaction. The S°for each species is shown below the reaction. C₂H₂(g) + 2H₂(g) → C₂H₆(g) S°(J K^-1 mol^-1) 200.9 130.7 229.2

Accepted Answer

Δ_rS° = Σ_rS°(products) - Σ_rS°(reactants) = S°(C₂H₆) + 2S°(H₂) - S°(C₂H₂) - 2S°(H₂) = 229.2 + 2(130.7) - 200.9 - 2(129.7) = -233.1 J K^-1 mol^-1. Therefore, the best choice is D.

Question 10

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. N₂H₄(l) + H₂(g) → 2NH₃(g) S° (J K^-1 mol^-1) 121.2 130.7 192.8

Accepted Answer

Δ_rS° = [2S°(NH₃)] - [S°(N₂H₄) + S°(H₂)]= [2(192.8)] - [121.2 + 130.7]= 385.6 - 251.9= +133.7 J K^-1 mol^-1

Question 11

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. C₂H₂(g) + H₂(g) → C₂H₄(g) S°(J J K^-1 mol^-1) 200.9 130.7 219.3

Accepted Answer

Δ_rS°= Σ_rS°(products) - Σ_rS°(reactants) = S°(C₂H₄) + S°(H₂) - [S°(C₂H₂) + S°(H₂)] = 219.3 + 130.7 - (200.9 + 130.7) = -112.3 J K^-1 mol^-1 Therefore, the best choice is C, which is the only option for a negative value of Δ_rS°.

Question 12

Identify the compound with the lowest standard Gibbs energy of formation.

Accepted Answer

NaCl(s) has a negative standard Gibbs energy of formation, indicating that it is thermodynamically favorable to form. The other compounds have positive standard Gibbs energies of formation, indicating that they are not as thermodynamically favorable to form.

Question 13

Which of the following is TRUE regarding allotropes?

Accepted Answer

Allotropes are different forms of the same element but with different physical and chemical properties, including standard molar enthalpies. For example, diamond and graphite are allotropes of carbon with different standard molar enthalpies. Therefore, option B is the true statement.

Question 14

Calculate ΔρS° for the following reaction. The S° for each species is shown below the reaction. P₄(g) + 10Cl₂(g) → 4PCl₅(g) S°(J K^-1 mol^-1) 280.0 223.1 364.6

Accepted Answer

ΔρS° = ΣS°(products) - ΣS°(reactants) = [4(364.6)] - [280.0 + 10(223.1)] = -1052.6 J K⁻¹ mol⁻¹.

Question 15

Which one of the following has the lowest standard molar entropy, S°, at 25 °C?

Accepted Answer

Helium has the lowest standard molar entropy because it is a monatomic gas.

Question 16

What is the name of the reaction that does not achieve the theoretical limits with respect to the change in Gibbs energy in thermodynamics?

Accepted Answer

An irreversible reaction does not achieve the theoretical limits with respect to the change in Gibbs energy in thermodynamics because energy is lost in the form of heat, and the reaction proceeds in one direction only, leading to an incomplete conversion of reactants to products. Reversible reactions, forward reactions, reverse reactions, and equilibrium reactions can all achieve the theoretical limits of Gibbs energy change.

Question 17

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Accepted Answer

The answer of Which one of the following has the...

Question 18

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Accepted Answer

The standard molar entropy of a gas is related to its molecular complexity. The more complex the molecule, the higher the entropy. Among the given choices, CH3CH2OH(g) is the most complex molecule, so it has the highest standard molar entropy.

Question 19

Given the following equation, N₂O(g) + NO₂(g) → 3 NO(g) Δ_rG° = -23.0 kJ mol^-1 Calculate Δ_rG° for the following reaction: 9NO(g) → 3N₂O(g) + 3NO₂(g)

Accepted Answer

The given reaction is the reverse of the original reaction multiplied by 3. Reversing the reaction changes the sign of ΔrG°, and multiplying by 3 scales it by 3. Thus, ΔrG° = 3 * 23.0 kJ mol⁻¹ = 69.0 kJ mol⁻¹.

Question 20

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Accepted Answer

N₂O₄(g) is a larger and more complex molecule compared to the diatomic gases, leading to more possible microstates and thus a higher standard molar entropy.

Quiz 17: Gibbs Energy and Thermodynamics

Given the following equation, N2O(g) + NO2(g) → 3NO(g) ΔrG° = -23.0 kJ mol-1 Calculate ΔrG° for the following reaction: 3N2O(g) + 3NO2(g) → 9NO(g)

What is the change in Gibbs energy of a process?

Identify the compound with the highest standard Gibbs energy of formation.

Given the following equation, N2O(g) + NO2(g) → 3NO(g) ΔrG° = -23.0 kJ mol-1 Calculate ΔrGo for the following reaction: 3NO(g) → N2O(g) + NO2(g)

Calculate ΔrS° for the following reaction. The S° for each species is shown below the reaction. 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) S°(J K-1 mol-1) 192.8 205.2 210.8 188.8

Identify the compound with the standard Gibbs energy of formation equal to zero.

What is the name of the reaction that achieves the theoretical limits with respect to the change in Gibbs energy in thermodynamics?

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Calculate ΔrS° for the following reaction. The S° for each species is shown below the reaction. C2H2(g) + 2H2(g) → C2H6(g) S°(J K-1 mol-1) 200.9 130.7 229.2

Calculate ΔrS° for the following reaction. The S° for each species is shown below the reaction. N2H4(l) + H2(g) → 2NH3(g) S° (J K-1 mol-1) 121.2 130.7 192.8

Calculate ΔrS° for the following reaction. The S° for each species is shown below the reaction. C2H2(g) + H2(g) → C2H4(g) S°(J J K-1 mol-1) 200.9 130.7 219.3

Identify the compound with the lowest standard Gibbs energy of formation.

Which of the following is TRUE regarding allotropes?

Calculate ΔρS° for the following reaction. The S° for each species is shown below the reaction. P4(g) + 10Cl2(g) → 4PCl5(g) S°(J K-1 mol-1) 280.0 223.1 364.6

Which one of the following has the lowest standard molar entropy, S°, at 25 °C?

What is the name of the reaction that does not achieve the theoretical limits with respect to the change in Gibbs energy in thermodynamics?

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Given the following equation, N2O(g) + NO2(g) → 3 NO(g) ΔrG° = -23.0 kJ mol-1 Calculate ΔrG° for the following reaction: 9NO(g) → 3N2O(g) + 3NO2(g)

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

Given the following equation, N₂O(g) + NO₂(g) → 3NO(g) Δ_rG° = -23.0 kJ mol^-1 Calculate Δ_rG° for the following reaction: 3N₂O(g) + 3NO₂(g) → 9NO(g)

Given the following equation, N₂O(g) + NO₂(g) → 3NO(g) Δ_rG°= -23.0 kJ mol^-1 Calculate Δ_rG^o for the following reaction: 3NO(g) → N₂O(g) + NO₂(g)

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) S°(J K^-1 mol^-1) 192.8 205.2 210.8 188.8

Calculate Δ_rS° for the following reaction. The S°for each species is shown below the reaction. C₂H₂(g) + 2H₂(g) → C₂H₆(g) S°(J K^-1 mol^-1) 200.9 130.7 229.2

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. N₂H₄(l) + H₂(g) → 2NH₃(g) S° (J K^-1 mol^-1) 121.2 130.7 192.8

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. C₂H₂(g) + H₂(g) → C₂H₄(g) S°(J J K^-1 mol^-1) 200.9 130.7 219.3

Calculate ΔρS° for the following reaction. The S° for each species is shown below the reaction. P₄(g) + 10Cl₂(g) → 4PCl₅(g) S°(J K^-1 mol^-1) 280.0 223.1 364.6

Given the following equation, N₂O(g) + NO₂(g) → 3 NO(g) Δ_rG° = -23.0 kJ mol^-1 Calculate Δ_rG° for the following reaction: 9NO(g) → 3N₂O(g) + 3NO₂(g)