A 8.60-g sample of solid CaSO4·2H2O was heated such that the water turned to steam and was driven off. Assuming ideal behavior, what volume would that steam occupy at 1.00 atm and 100.0 °C?

Answer 1

Calculate %H2O in CaSO4.2H2O by
(2*molar mass H2O/molar mass CaSO4.2H2O)*100 = ?

8.60g sample x %H20/100 = grams H2O driven off. Convert to mols. Then use PV = nRT and the conditions listed and solve for V in Liters.