Standard Electrode Potential (E°) Calculator
E° values measured relative to the SHE for comparing oxidizing/reducing strength.
Formula first
Overview
Standard Electrode Potential (E°) is the intrinsic voltage of a half-cell under standard conditions, measured relative to the Standard Hydrogen Electrode (SHE). It defines the thermodynamic tendency of a chemical species to gain electrons and undergo reduction, with the SHE potential set at exactly 0.00 V.
Symbols
Variables
E^ = Standard Potential
Apply it well
When To Use
When to use: Use this value when calculating the standard cell potential for a redox reaction or determining the spontaneity of a chemical process. It is applicable only under standard conditions: 1 M concentration for solutes, 1 atm partial pressure for gases, and a temperature of 298.15 K.
Why it matters: It is the foundation for the electrochemical series, allowing scientists to predict which metals will corrode or which reactions can be driven by an external power source. This data is essential for developing high-energy density batteries and designing industrial electrolytic processes like electroplating.
Avoid these traps
Common Mistakes
- Forgetting standard conditions (1 M, 1 atm, 298 K).
- Reversing sign when writing reduction.
One free problem
Practice Problem
A standard half-cell containing Chlorine gas and Chloride ions (Cl₂/Cl⁻) is measured against a Standard Hydrogen Electrode. If the voltmeter shows a potential difference of 1.36 V and the Chlorine electrode acts as the cathode, what is the standard electrode potential (E0) of the Chlorine half-reaction?
Solve for:
Hint: The Standard Hydrogen Electrode (SHE) is assigned a potential of exactly 0.00 V.
The full worked solution stays in the interactive walkthrough.
References
Sources
- Atkins' Physical Chemistry
- IUPAC Gold Book: Standard electrode potential
- Wikipedia: Standard electrode potential
- Atkins' Physical Chemistry (11th ed.)
- NIST Chemistry WebBook
- AQA A-Level Chemistry — Redox and Electrode Potentials