# During the electrolysis of copper(II) sulfate solution using copper electrodes, describe what happens at each electrode and explain why the concentration of copper(II) sulfate solution remains constant throughout the process.

> Cambridge International IGCSE Chemistry (0620) — 4.1 Electrolysis · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. At the cathode, copper is deposited / copper ions gain electrons
2. At the anode, copper dissolves / the anode loses mass / copper atoms lose electrons
3. The rate at which copper is removed from solution at the cathode equals the rate at which copper enters solution from the anode
4. Therefore the number of copper(II) ions in solution stays the same / concentration of Cu²⁺ ions does not change

## Key terms

- [electrolysis](https://www.gradenine.co.uk/glossary/electrolysis)
- [copper(II) sulfate solution](https://www.gradenine.co.uk/glossary/copper-ii-sulfate-solution)
- [concentration](https://www.gradenine.co.uk/glossary/concentration)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/during-the-electrolysis-of-copper-ii-sulfate-a65707d6) · Published by Druglandscape Ltd.