If you are making 180.0 mL of 3.00% (m/m) CuSO45 H2O, how many grams of the solute should you use?

Question

I can't figure out what to do with the percent.

Answer 1

3% solution = 3 g solute/100 g solution or
3 g CuSO4.5H2O/100 g solution.

You need to know the density of the solution to convert from m/m to 180.0 mL. Since the solution is relatively dilute, the density should be close to 1.00 g/mL so the 180 mL will have a mass of 180 g and you will need 3 x (180/100) = ?? g CuSO4.5H2O BUT ONLY IF THE DENSITY IS 1.00 g/mL.