Gibbs Energy And Electrochemistry
For a galvanic cell with E°cell = 0.59 V and n = 2, the standard Gibbs energy change (ΔG°) of the cell reaction at 298 K is approximately (F = 96500 C mol⁻¹):
Select the correct option:
Solution
-113.87 kJ mol⁻¹
The relationship between Gibbs energy and cell potential is ΔG° = −nFE°cell. Substituting the values: ΔG° = −2 × 96500 × 0.59 = −2 × 56935 = −113870 J mol⁻¹ ≈ −113.87 kJ mol⁻¹. The negative value of ΔG° confirms that the cell reaction is thermodynamically spontaneous under standard conditions, which is consistent with the positive E°cell. This equation is the bridge between electrochemistry and thermodynamics — a positive cell EMF always corresponds to a negative (spontaneous) Gibbs energy change.
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About This Question
- Subject
- chemistry
- Chapter
- redox reactions and electrochemistry
- Topic
- gibbs energy and electrochemistry
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
-113.87 kJ mol⁻¹
The relationship between Gibbs energy and cell potential is ΔG° = −nFE°cell. Substituting the values: ΔG° = −2 × 96500 × 0.59 = −2 × 56935 = −113870 J mol⁻¹ ≈ −113.87 kJ mol⁻¹. The negative value of ΔG° confirms that the cell reaction is thermodynamically spontaneous under standard conditions, which is consistent with the positive E°cell. This equation is the bridge between electrochemistry and thermodynamics — a positive cell EMF always corresponds to a negative (spontaneous) Gibbs energy change.
This medium difficulty chemistry question is from the chapter redox reactions and electrochemistry, covering the topic of gibbs energy and electrochemistry. It appeared in the 2025 exam.
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