Aluminium will react with copper(II) sulfate solution according to the following equation:
2Al (s) + 3CuSO4 (aq) " 3Cu (s) + Al2(SO4)3 (aq)
The reaction is quite slow at room temperature, but when chloride ions in the form of hydrochloric acid are added, the rate increases significantly. The chloride ions catalyse the reaction.
An experiment was carried out to determine the yield of the reaction. A student made a solution of aqueous copper(II) sulfate by dissolving 2.00 g of copper(II) sulfate pentahydrate, CuSO4.5H2O (Mr 249.72 g mol-1) in 10.0 mL of distilled water in a small beaker.
To this solution she added 0.25 g of aluminium foil followed by 2.0 mL of 6.0 mol dm-3 hydrochloric acid.
After the reaction was complete, she collected, dried, and weighed the copper that was produced.
She recorded the measurements in Table 1 below.
Table 1
|
Mass / ± 0.01 g
|
Initial mass of copper sulfate
|
2.00
|
Mass of aluminium foil used
|
0.25
|
Mass of empty beaker
|
42.18
|
Mass of beaker with dry copper
|
42.61
|
Use the data to show that the copper sulfate is the limiting reagent in the experiment and calculate the mass of aluminium in excess.