If 4.02 grams of a hydrate of magnesium sulfate loses 2.06 grams of water when heated, what is the formula for the hydrate

Answer 1

mass H2O = 2.06
mass salt = 4.02-2.06 = 1.96

mols H2O = 2.06/18 = about 0.114
mols MgSO4 = 1.96/120.4 = 0.0163
0.114/0.0163 = 7.00; therefore, the formula is
MgSO4.7H2O