CuSO4 ¯¿½ 5H2O and MgSO4 ¯¿½ 5H2O. There are 5 water molecules per Copper (II) Sulphate and 7 water molecules per Magnesium Sulphate. The compounds are all hydrates which is a substance that contains water. This occurs when crystals form from the evaporation of an aqueous solution of a salt and water molecules become included into the crystal. The hydrates were heated and lost its water of hydration and made it possible to calculate how much water was in the hydrate and the water to salt ratio. The percentage error for the Copper (II) Sulfate was 4.61%. It is a large error but the coefficient was correctly rounded to the accepted value of 5. The percentage error for Epsom salts was 5.51% which is also very large but can also be rounded to the accepted value of 7.
Errors and Limitations
Without a lid on the evaporating dish, the powder popped out the dish when heated therefore causing the mass of the remaining substance to be lower
Using a lid
Imprecise measurements of mass
Causing the mass of the evaporating dish, H2O and the remaining hydrate to be lowered or raised and therefore makes the final formula incorrect
Making sure the surface of the scale is clean and waiting until the weight displayed has completely stopped
No depth in experiment
More experiments can be done for comparison and further our knowledge of hydrates
Another Sulfate hydrate to compare the hydrates and see if there is a pattern of the different hydrate and the number of water molecules due to factors of periodicity. Also we could have also just used sulfate hydrate to observe how adding another element affect the water and salt ratio.
Overheating of the substances
The hydrates were heated under the Bunsen burner and were left under the heat for too long. This could alter the result by lowering the mass, which would increase the water to salt ratio.
Mixing the powder to evenly distribute the heat to prevent overheating the salt.
Not letting the substance cool before weighing it
This would raise the mass of the anhydrate because the water molecules would not be entirely evaporated making the substance left heavier.
Having more patience and letting the salt completely cool before weighing
Oval chunks of CuSO4 remain after burning
Not all of the water of hydration has been removed which will throw off the result by decreasing the mole of water and the increase the final water to salt ratio.
Break up the chunks before heating or while heating.