A manufacturer is testing a prototype power source for a kitchen timer. The prototype has two copper electrodes dipped in a liquid electrolyte. Spare zinc and copper electrodes and more of the electrolyte are available.
Which change would make the prototype work as a simple cell, and why?
Add more of the same electrolyte, so that both copper electrodes are covered completely by it.
Make the two copper electrodes touch, so that the circuit inside the cell becomes complete.
Replace one copper electrode with a zinc electrode, so that the two electrodes are different metals.
Use larger copper electrodes, so that more copper can react and a voltage is then produced.
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.