Question

How many grams of solid CuSO4. 5H2O are needed to prepare a 500 ml of a 1000 ppm solution of Cu?

Answer 1

You want 1000 ppm Cu. You have CuSO4.5H2O; how much of that do you need? That is 1000 x (molar mass CuSO4.5H2O/atomic mass Cu) = approx 3930 g CuSO4.5H2O. That is 3930 grams CuSO4.5H2O/10^6 g solution. You don't want 10^6 g solution, only want 500 g.
500 x (3930/1E6) = about 2 g but you need to do all of the calculations more accurately than above.

Answer 2

Dear it is not 3930 g it is 3930 mg