Answer:
X = 5
Explanation:
The molar ratio of water to copper(II) sulfate must be found.
The mass of water that must have been eliminated from the salt is found by the difference in weight before and after:
(500 g) - (320 g) = 180 g water eliminated
The moles of water (MW 18.02 g/mol) is then found:
(180 g) / (18.02g/mol) = 9.9889...mol
The mass of the dehydrated copper(II) sulfate (MW 159.609 g/mol) is converted to moles:
(320 g) / (159.609 g/mol) = 2.004899...mol
The molar proportion of water to the copper(II) sulfate is then calculated:
(9.9889...mol H₂O) / (2.0034899...mol CuSO₄) ≅ 5