Apentix/AP Chemistry/Unit 9: Applications of Thermodynamics/Question
AP Chemistryhardmcq1 pt

A galvanic cell runs with n = 3 and E°cell = +0.44 V. If the overall cell reaction is written in reverse, what are the new E°cell and ΔG°?

A.Both flip: E°cell = −0.44 V and ΔG° = +127 kJ
B.Only the free energy flips: E°cell stays +0.44 V while ΔG° = +127 kJ
C.Only E flips: E°cell = −0.44 V while ΔG° stays −127 kJ
D.Neither changes: E°cell = +0.44 V and ΔG° = −127 kJ

Explanation

Core Concept

Forward, ΔG° = −nFE°cell = −(3)(96,485)(0.44) ≈ −127 kJ. Reversing an equation negates every state-function change, so ΔG° becomes +127 kJ while E° flips to −0.44 V. The reversed cell is nonspontaneous and would need an outside supply to run. Magnitudes survive unchanged because the identical chemistry occurs to the same extent.

Correct Answer

ABoth flip: E°cell = −0.44 V and ΔG° = +127 kJ

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