I am not feeling myself at the moment. I cant think and I need someone to verify my calculations.
I made up a 5ppm solution of Copper(II)sulphate solution in a 50cm volumetric flask.
5 ppm = 5mg/L
Therefore there are 5mg of Cu(II) ions per litre giving.
Moles = 5x10^-3 / 63.55 = 7.87x10^-5 moles.
Concentration = Moles x1000 / V
Therefore:
C = 7.87x10^-5 x 1000 / 50
C = 1.57 x 10^-3 mol dm^3
Is this correct?