Table 1 shows the mass measurements of copper electrodes before and after the electrolysis of copper sulfate solution for 15 minutes.
| Electrode | Mass before electrolysis (g) | Mass after electrolysis (g) | Change in mass (g) |
|---|---|---|---|
| Anode (positive electrode) | 5.82 | 4.95 | -0.87 |
| Cathode (negative electrode) | 5.50 | 6.35 | +0.85 |
Explain, in terms of copper atoms and ions, the changes in mass of the two electrodes shown in Table 1.
83 exam-style questions on Edexcel GCSE Chemistry 4.2 Electrolytic processes, covering 4.2.1 Electrolytes and the process of electrolysis, 4.2.2 Products of electrolysis using inert electrodes, 4.2.3 Half equations, oxidation and reduction in electrolysis, and 4.2.4 Electrolysis of copper sulfate and purifying copper. Each one has a worked solution and a mark scheme showing where the marks go.