Question: how to find moles of water of crystallization?
Answer: The mass ratio of CuSO4 : H2O is 4.00 : 2.25. To convert from mass ratio to mole ratio, you divide by the molecular mass of each 'species' CuSO4 = 64 + 32 + (4x18) = 160 and H2O = 1+1+16 = 18. The mole ratio of CuSO4 : H2O is 4.00/160 : 2.25/18.