Aim- To determine the percentage content of water (H2O) in hydrated copper sulphate crystals (Cu (ÉÉ) SO4 . 5H2O).
Equipment- Approximately 1 gram of copper sulphate crystals, evaporating dish, tongs, Bunsen burner, gauze, tripod, spatula, weighing balance.
Method- a) Set up the Bunsen burner, gauze and tripod.
b) Weigh the evaporating dish.
c) Weigh the evaporating dish and approximately 1 gram of copper sulphate crystals.
d) Gently heat the copper sulphate crystals in the evaporating dish, until they appear to be white (If heated too much, the crystals will break down further and turn yellow.).
e) Take the evaporating dish away from the heat with the tongs, and weigh the evaporating dish containing the now white crystals.
f) To determine the percentage water, you subtract the weight of the crucible from the final weight, and then you subtract the weight of the substance left from the initial weight of the copper sulphate crystals.
Safety- When setting up the experiment, make sure that the Bunsen burner, tripod and gauze are placed away from the edge of the table. .
Also, all bags and coats should be removed from the area, so to avoid hazard.
Safety glasses should be worn at all times throughout the experiment. .
You must use the tongs to lift the evaporating dish from the gauze.
Variables- The first variable will be the amount of hydrated copper sulphate crystals used at the start. .
Also the temperature of the bunsen burner flame will be another variable, and also the length of time that the crystals are heated for.
The amount of water lost is also a variable, as this will change for each of the experiments. The mass of Cu (ÉÉ) SO4 . 5H2O should remain constant.
Range- Due to the nature of this experiment, there is no specified range.
Prediction- To predict the percentage water in Cu (ÉÉ) SO4 . 5H2O crystals, we first have to calculate the "Ar-, or mass number of each of the elements involved, adding each side of the equation's numbers together, to form a "Mr- for each side.