
53Review of Electrochemistry
Every cell reaction consists of a reduction reaction and an oxidation reac-
tion. Hence, every cell must be constructed to employ one reaction and
another reaction written opposite. The cell potential is calculated as
E
cell
= E
cathode
– E
anode
. (2.35)
For example, the reduction reaction Au
+
+ e
–
→ Au and oxidation reaction
Cu → Cu
2+
+ 2e
–
gives the overall reaction after taking a balance on electrons:
2Au
+
+ Cu → Cu
2+
+ 2Au. The potential for this cell is E = +1.69 – 0.34 = +1.35V.
Thus, a cell constructed using an Au and a Cu electrode and solutions of
Au(I) and Cu(II) ions, when at unit activity (1.00 M), has a ...