An electroplating experiment is set up to coat a metal object with nickel using a nickel sulfate solution and nickel electrodes. The electrolysis is run for a duration of 30 minutes.
The table below shows the results of this experiment:
| Anode | Cathode | |
|---|---|---|
| Mass of electrode before electrolysis (g) | 12.50 | 12.40 |
| Mass of electrode after electrolysis (g) | 12.13 | 12.75 |
| Change in mass (g) | −0.37 | +0.35 |
The experiment is repeated under identical conditions with a new cell using a fresh pair of nickel electrodes with the same starting masses.
Explain a change that could be made to the apparatus or circuit to cause the mass of the cathode to increase by exactly 1.40 g in the same 30-minute period.
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.