Cell Potential

In-depth explanation of Cell Potential

The cell potential is the voltage of a complete electrochemical cell and is calculated as the cathode reduction potential minus the anode reduction potential. A positive value indicates a spontaneous reaction under the conditions used. The value is an intensive property and does not change when the stoichiometric coefficients of the balanced equation are multiplied. Because it depends on the difference between two potentials, it does not depend on the choice of reference electrode. Cell potential links thermodynamics to measurable voltage.

Going deeper: Cell Potential

Key ideas: E cell = E cathode - E anode (using reduction potentials). Positive E means spontaneous as written. Example: Zn/Cu cell gives 0.34 - (-0.76) = 1.10 V. Under nonstandard conditions use the Nernst equation. Cells in series add voltage: six 2 V lead-acid cells make 12 V.

Common mistakes and connections: Errors: adding the anode potential after already reversing its sign, or subtracting twice, and changing E when balancing coefficients. Voltage is the driving force per unit charge, not how much total energy is available, which depends on charge too. Related to delta G and equilibrium constants.

Visualization of Cell Potential

Cell potential equals E(cathode) minus E(anode), so pairing metals farther apart in the series gives a larger voltage, such as 1.10 V for Zn-Cu. The interactive lesson shows this as a live animation or chart.

Worked example and use case

For a zinc-copper cell, E cell = 0.34 V - (-0.76 V) = 1.10 V.

Where Cell Potential fits in Acids, Bases & Electrochemistry

Cell Potential is topic 52 of 105 in Acids, Bases & Electrochemistry.

Related topics

• Cell NotationIntermediate
• Standard Electrode PotentialIntermediate
• Standard Hydrogen ElectrodeIntermediate
• Electrochemical SeriesIntermediate
• Spontaneity from Cell PotentialIntermediate
• Nernst EquationAdvanced

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