Before performing an electrolysis experiment using copper electrodes and copper(II) sulfate solution, a student measured the initial mass of each electrode. After the electrolysis was complete, the electrodes were rinsed, dried, and weighed again.
The table below shows the results of this experiment.
| Electrode | Mass of electrode before electrolysis in g | Mass of electrode after electrolysis in g | Change in mass of electrode in g |
|---|---|---|---|
| Anode | 15.45 | 14.82 | −0.63 |
| Cathode | 14.18 | 14.81 | +0.63 |
Explain these results.
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.