Cell X powers an automatic flood-warning station. Methanol and oxygen from the air enter the cell through separate supply tubes.
A technician changes the methanol supply and records the potential difference.
| Time / min | Methanol supply | Oxygen supply | Potential difference / V |
|---|---|---|---|
| 0 | supplied | supplied | 0.7 |
| 10 | stopped | supplied | 0.0 |
| 20 | supplied again | supplied | 0.7 |
Explain how the results show that X is a fuel cell rather than a chemical cell containing stored reactants.
At 30 min, methanol continues to be supplied but the oxygen supply is stopped. Predict the potential difference after the oxygen already in X has reacted. Justify your prediction.
131 exam-style questions on OCR GCSE Chemistry 6.2 Organic chemistry, covering 6.2.1 Crude oil and fractional distillation, 6.2.2 Cracking and dependence on hydrocarbons, 6.2.3 Functional groups and homologous series, 6.2.4 Reactions of alkanes, alkenes and alcohols, 6.2.5 Addition polymerisation and repeat units, 6.2.6 Naturally occurring polymers, 6.2.7 Chemical cells and fuel cells, and 6.2.8 Condensation polymerisation and how to make one. Each one has a worked solution and a mark scheme showing where the marks go.