# chem

posted by
**mocha81** on
.

a 2.50g sample of hydrate of calcium sulfate losses 0.523g of water when heated. what is the mass percent of water in the hydrate and the formula for the hydrate

difference of the two masses divided by the initial mass.

I believe Adam should reconsider his answer.

mass percent water = [amount water/mass sample]*100 = (0.523/2.50)*100 = ??

For the formula of the hydrate.

mols H2O = 0.523/18.01 = ??

mols CaSO4 = (2.50 - 0.523)/molar mass CaSO4 = ??

Find the ratio of mols water to 1 mol CaSO4, then express that as CaSO4.xH2O where x is the mols H2O per 1 mol CaSO4.

Post your work if you get stuck.