Question

How many grams of CuSO4 (dot) H2O are needed to prepare 50 mL of a 4% (w/v)solution of CuSO4?

Answer 1

Answer – Given, mass by volume percent = 4 % , volume = 50 mL

So, mass of CuSO₄ = ?

mass by volume percent = mass of solute / total volume * 100 %

so, mass of CuSO₄ = mass by volume percent * total volume / 100 %

                               = 4.0 % * 50 mL /100 %

                               = 2.0 g

Now we need to calculate the moles of CuSO₄

CuSO₄ = 2.0 g / 159.61 g.mol^-1

            = 0.0125 moles

1 mole of CuSO₄ = 1 moles of CuSO₄.H₂O

0.0125 moles CuSO₄ = ?

= 0.0125 moles CuSO₄.H₂O

So, mass of CuSO₄.H₂O = 0.0125 moles * 177.32 g/mol

                                        = 2.23 g