Derive a balanced equation for the reaction occurring in the cell: Fe(s)|Fe2+(aq)|| Fe3+(aq), Fe2+(aq)|Pt(s) (a) If E ? cell = 1.21 V, calculate ? G ? and the equilibrium constant for the reaction. (b) Use the Nernst equation to determine the potential for the cell at 25 ?C: Fe(s)|Fe2+(aq) (1 . 0 × 10 ? 3 M )|| Fe3+(aq) (1 . 0 × 10 ? 3 M ), Fe2+(aq) (1 . 0 × 10 ? 3 M )|Pt(s) Answers: (a) ? G ? = ?233 . 5 × 10 ? 3 J /mol and K = 8 . 1 × 1040 and (b) 1.30 V