When 0.228 g of the hydrate ZnSO4•xH2O is heated, 0.128 grams of anhydrous ZnSO4 remains. What is the value of x in the formula for the hydrate? (hint: remember that x represents the ratio of moles of H2O to moles of hydrate compound, and that moles of hydrate compound equals the moles of anhydrous compound)