Find the amount of CuSO4.5H2O needed to prepare 500 mL of 0.25 M solution.

Answer 1

How many moles do you need?
That is M x L = moles.

Then moles CuSO4.5H2O = grams CuSO4.5H2O/molar mass CuSO4.5H2O
You know moles and molar mass, solve for grams.