How is the cell potential (E°) calculated?

The cell potential (E°), also called the electromotive force (EMF) of an electrochemical cell, is calculated using the standard electrode potentials of the two half-cells.

Here’s how it works conceptually (without equations):

1. Identify the cathode (where reduction occurs) and the anode (where oxidation occurs).
2. Determine the standard reduction potential of each half-cell.
3. The cell potential is found by subtracting the anode potential from the cathode potential.

In simple terms:

• The cathode potential tells how easily a species is reduced.
• The anode potential tells how easily a species is oxidized (as a reduction potential, it is subtracted).
• The difference gives the overall voltage the cell can produce under standard conditions.

This standard cell potential indicates the tendency of the cell to produce electricity spontaneously.