If you needed 2.50g of CuSO4 for a reaction but only had CuSO4 * 5H2O available, how many g would you need to use to get the same number of moles of CuSO4?

Answer 1

2.5/molar mass CuSO4 = moles CuSO4.
You need the same moles CuSO4.5H2O.
moles CuSO4.5H2O = mols x molar mass.