This question is about chemical cells.
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 X.
- Record the cell voltage.
- Repeat steps 1 and 2 using different metals as electrode X.
a.[2]
Suggest two variables that must be controlled in this investigation to ensure valid results.
b.
[2]
Table 1 shows the student's results:
| Electrode X | Voltage of cell in volts (V) |
|---|---|
| copper | -0.78 |
| iron | 0.00 |
| lead | -0.31 |
| magnesium | +1.93 |
| nickel | -0.19 |
| zinc | +0.32 |
Write the six metals used for electrode X 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 nickel
- Magnesium and nickel
- Magnesium and copper
- Zinc and copper