ΔG° from cell potential
A reaction transfers 2 moles of electrons and has E°cell = +0.50 V. Using F ≈ 96,500 C/mol, what is ΔG°?
Answer B: explanation for every choice
A
This doubles the result, as if n were 4.
B
Correct. ΔG° = −nFE° = −(2)(96,500)(0.50) = −96,500 J ≈ −96.5 kJ.
C
This uses n = 1.
D
This drops the negative sign. A positive E° means ΔG° is negative.
TakeawayΔG° = −nFE°. Positive E° ↔ negative ΔG° ↔ spontaneous.
Equation usedFree energy and cell potential
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