This question is about chemical cells and batteries.
A student investigated the voltage produced by different chemical cells using the apparatus shown below.
The student used the following method:
- Use magnesium as Electrode Y.
- Record the cell voltage.
- Repeat steps 1 and 2 using different metals as Electrode Y.
a.[2]
Suggest two variables that must be controlled in this investigation to ensure valid results.
b.
[3]
Table 1 shows the student's results when compared to a Nickel reference electrode:
| Electrode Y | Voltage of cell (V) |
|---|---|
| Silver | -1.05 |
| Zinc | +0.51 |
| Lead | -0.11 |
| Copper | -0.59 |
| Magnesium | +2.15 |
| Iron | +0.19 |
Write the six metals used for Electrode Y in order of reactivity from most reactive to least reactive. Justify your order using the data.
c.[1]
Which of the following pairs of metals would produce the greatest voltage when used as the electrodes in a similar cell? Use the data in Table 1.
- Zinc and Silver
- Magnesium and Silver
- Magnesium and Lead
- Iron and Copper