Each copper(II) sulfate unit is associated with five water molecules in crystalline copper(II) sulfate pentahydrate (CuSO 4 5 H 2 O).

Each copper(II) sulfate unit is associated with five water molecules in crystalline copper(II) sulfate pentahydrate (CuSO4· 5 H2O). When this compound is heated in air above 100°C, it loses the water molecules and also its blue color.

CuSO4·5 H2O------>  CuSO4 + 5 H2O

If 8.80 g of CuSO4 are left after heating 13.76 g of the blue compound, calculate the number of moles of H2O originally present in the compound.