# Describe how a pure, dry sample of copper(II) sulfate crystals could be prepared starting from copper(II) oxide and dilute sulfuric acid.

> Cambridge International IGCSE Chemistry (0620) — 7.3 Preparation of salts · Describe · 4 marks

## Mark scheme (4 marks)

1. Add excess copper(II) oxide to the dilute sulfuric acid
2. Filter to remove the excess (unreacted) copper(II) oxide
3. Heat / evaporate the filtrate to concentrate the solution
4. Allow the solution to cool so that copper(II) sulfate crystals form, then dry the crystals

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