Copper sulphate crystals contains `25.45 % Cu and 36.07 % H_(2)O`. If the law of constant composition is true, calculate the weight of copper required to obtained `40 g` of crystalline copper sulphate.

Explanation

The chemical formula of copper sulphite crystals is `CuSO_(4).5H_(2)O`. According to the data,
Percentage of `Cu = 25.45 % ` , Percentage of `H_(2)O = 36.07 %`
Percentage of `SO_(4) = 100-(25.45 +36.07) = 100-61.52 = 38.48 %`
Since the law of constant composition is true, the percentage composition of the other sample of copper sulphite crystals must also remais the same
Now, 100 g of copper sulphate crystals contain `Cu = 25.45 g`
`:.` 50 g of copper crystals contain `Cu=((25.45g))/((100g))xx(40g)=10.18g`.