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The following reaction occurs during rusting of iron 2H + + 2e + 1 2 O 2 → H 2 O; E o = +1 .23 V Fe 2+ + 2e → Fe (s); E o = 0 .44 V Calculate magnitude of ΔG o (kJ) for the net process Fe (s) + 2H + + 1 2 O 2 → Fe 2+ + H 2 O

Correct answer

322

Step-by-step solution

Fe(s) → Fe 2+   +   2e − ;   ΔG 1 o 2H + + 2e − + 1 2 O 2 → H 2 O(l); ΔG 2 o Fe(s) + 2H + + 1 2 O 2 → Fe 2+ + H 2 O; ΔG 3 o Applying, ΔG 1 o + ΔG 2 o = ΔG 3 o ΔG 3 o = − 2F × 0 .44 + − 2F × 1 .23 ΔG 3 o = − 2 × 96500 × 0 .44 + − 2 × 96500 × 1 .23 ΔG 3 o = − 322310 J ∴ ΔG 3 o = − 322 kJ

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