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Calculate the equilibrium constant at 25°C for the cell reaction: Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s). Given: E_cell_standard for Fe/Fe²+ = +0.453 V and E_cell_standard for Cu/Cu²+ = -0.3435 V.

1. 1.0 × 10²⁵
2. 1.0 × 10²⁰
3. 1.0 × 10²⁷
4. 1.0 × 10²²

Correct answer: 1.0 × 10²⁷

Solution

The standard cell EMF is E_cell = 0.3435 + 0.453 = 0.7965 V (using reduction potentials, Cu is cathode, Fe is anode). n=2 electrons. log(K) = n*E_cell/0.0591 = 2*0.7965/0.0591 ≈ 26.95 ≈ 27. Therefore K ≈ 10²⁷.

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