Calculating the emf from standard potentials:
A galvanic cell consists of an `Al` electrode in a `1.0M Al(NO_(3))_(3)` solution and an `Fe` electrode in a `1.0M Fe(NO_(3))_(2)` solution. Calculate the standard emf of this electrohemical cell at `25^(@)C`. Also write the cell reaction.
Strategy: From the table of standard electrode potentials, write the two reduction half reaction and standard electrode potentials for the cell. Change the direction of the half-cell reaction corresponding tol the smaller (or more negative) electrode potential. Multiply the when the half-reactions are added the electrons cancel. The sum of the half-reactions is the cell reaction. Add the electrode potentials to get the cell emf.