How can I determine the Mass percent of water in the hydrate and the formula of the hydrate??

Question

If a 2.50 g sample of a hydrate of calcium sulfate loses .523g of water when heated??

How do I find the formula of the hydrate??

Answer 1

You just take the number of grams of water lost after the heating and divide it by the total number of grams in the hydrate, so it would be .523g/2.50gx100 would give you the mass percent of the hydrate, which using correct significant figures would be 20.9%