Cell EMF Calculator

The Cell EMF Calculator computes the electromotive force (EMF) of a galvanic (voltaic) cell from standard electrode potentials of the anode and cathode.

$$E^\circ_{\text{cell}} = E^\circ_{\text{cathode}} - E^\circ_{\text{anode}}$$

In a spontaneous galvanic cell, oxidation occurs at the anode (lower potential) and reduction at the cathode (higher potential). The Daniell cell is a classic example: zinc acts as the anode ($E^\circ = -0.76$ V) and copper as the cathode ($E^\circ = +0.34$ V), giving $E^\circ_{\text{cell}} = 1.10$ V.

Frequently Asked Questions

What is EMF in electrochemistry?

EMF (electromotive force) is the potential difference between cathode and anode in a galvanic cell. It measures the cell's ability to drive electric current through an external circuit under standard conditions.

Why is the anode negative in a galvanic cell?

The anode is where oxidation occurs and electrons are released. Those electrons flow through the external circuit toward the cathode, making the anode the negative terminal in a galvanic cell.

What does a negative cell EMF mean?

A negative EMF means the reaction as written is not spontaneous. Reversing anode and cathode roles would give a positive EMF and a spontaneous cell.

How is the Daniell cell EMF calculated?

For Zn and Cu electrodes: $E^\circ_{\text{cell}} = (+0.34) - (-0.76) = 1.10$ V. Zinc oxidizes and copper ions reduce, producing a spontaneous 1.10 V cell.

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Cell EMF Calculator

Cell EMF Calculator

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