A recycling company has four different metal offcuts, P, Q, R and S. Metal P is known to be more reactive than each of the other metals.
A chemist makes three simple cells to check the proposed order of decreasing reactivity:
P, Q, R, S
Apart from the metal combination and the electrolyte shown, the conditions are the same for each cell.
| Metal electrodes | Electrolyte | Voltage in V |
|---|---|---|
| P and Q | 1 | 0.44 |
| P and R | 1 | 0.81 |
| P and S | 2 | 1.18 |
Explain why the first two results can be used to decide whether Q or R is more reactive. State the conclusion.
Evaluate whether the results support the complete proposed order. Suggest one change that would allow all four metals to be compared.
90 exam-style questions on AQA GCSE Chemistry 5.2 Chemical cells and fuel cells, covering 5.2.1 Cells and batteries, 5.2.2a Fuel cells, and 5.2.2b Half equations for hydrogen fuel cells. Each one has a worked solution and a mark scheme showing where the marks go.