# Explain why standard electrode potentials must be measured under standard conditions, and state what those standard conditions are.

> AQA A-Level Chemistry (7405) — 3.1.11 Electrode potentials and electrochemical cells (A-Level only) · Explain · 5 marks

## Mark scheme (5 marks)

1. Electrode potential varies with concentration (or temperature or pressure)
2. Standard conditions allow valid comparison between different half-cells / electrode potentials
3. Ion concentration of 1 mol dm⁻³ (for all solutions)
4. Temperature of 298 K (or 25 °C)
5. Pressure of 100 kPa (or 1 atmosphere / 101 kPa accepted)

## Key terms

- [standard electrode potential](https://www.gradenine.co.uk/glossary/standard-electrode-potential)
- [standard conditions](https://www.gradenine.co.uk/glossary/standard-conditions)

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-standard-electrode-potentials-must-fe3d87cd) · Published by Druglandscape Ltd.