A voltaic cell consists of a half-cell of iron ions in a solution with [Fe2⁺] = 2.0 M and

[Fe3⁺] = 0.75 M , and a half-cell of copper metal immersed in a solution containing Cu²⁺ at a concentration of 3.6 × 10^-4 M . What is the voltage of this cell?

Strategy First, determine E° for the spontaneous reaction and the number of electrons transferred. Then, substitute the nonstandard concentrations into the expression for Q and solve the Nernst equation for E.