A student investigates how the voltage of a simple cell depends on the metals used. The student places a strip of copper and a strip of another metal into a beaker of sodium chloride solution and connects them to a voltmeter. The student repeats each experiment three times.
The table shows the results.
| Second metal | Voltage 1 / V | Voltage 2 / V | Voltage 3 / V | Mean voltage / V |
|---|---|---|---|---|
| magnesium | 1.62 | 1.58 | 1.60 | 1.60 |
| zinc | 0.78 | 0.82 | 1.20 | |
| iron | 0.46 | 0.44 | 0.45 | 0.45 |
State the dependent variable in this investigation.
Give two variables that the student should keep the same.
Identify the anomalous result.
Calculate the mean voltage for zinc. Do not include the anomalous result.
The student leaves the magnesium and copper cell connected for several days. The voltage falls to zero. Suggest why.
Aluminium is more reactive than zinc but less reactive than magnesium. Predict whether a cell made with copper and aluminium would give a higher or lower voltage than the zinc and copper cell. Explain your answer.
38 exam-style questions on Edexcel GCSE Chemistry 6.4 Chemical cells and fuel cells, covering 6.4.1 Chemical cells and fuel cells. Each one has a worked solution and a mark scheme showing where the marks go.