Electromotive Force (EMF)
| Formula / Notation | EMF = E_cell = E_cathode − E_anode; ΔG = −nFE |
|---|---|
| Also Known As | Cell EMF, cell potential, open circuit voltage (OCV), E_cell |
What is Electromotive Force (EMF)?
The maximum potential difference between the electrodes of a galvanic cell when no current flows, measured in volts. EMF represents the driving force for electron flow in an electrochemical cell and equals the sum of the electrode potentials at the cathode and anode.
Formula & Notation
Other Names / Synonyms: Cell EMF, cell potential, open circuit voltage (OCV), E_cell
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The maximum potential difference between the electrodes of a galvanic cell when no current flows, measured in volts. EMF represents the driving force for electron flow in an electrochemical cell and equals the sum of the electrode potentials at the cathode and anode.
EMF measurements are used to determine standard electrode potentials, calculate equilibrium constants (ΔG° = −nFE° = −RT ln K), monitor battery state of charge, and in potentiometric titrations and pH measurement (glass electrode). Thermodynamic data (ΔG, ΔH, ΔS) can be extracted from EMF-temperatur…
High EMF cells (e.g., 400 V lithium-ion battery packs in electric vehicles) present severe electrocution hazards. Always discharge high-voltage systems before working on them. Measuring EMF of unknown cells requires appropriate high-impedance voltmeters and insulated probes.
The formula or notation for Electromotive Force (EMF) is: EMF = E_cell = E_cathode − E_anode; ΔG = −nFE