Using the fact that fresh water has a density of 1000 kg/m3 , show that 5ppm Pb = 5 mg/L Pb .

Answer 1

I assume that is ppm w/v.
5 ppm = 5 g Pb/10^6 g H2O =
5 mg Pb/10^3 g H2O =
5 mg Pb/1000 g H2O =
5 mg Pb/1L H2O if density of H2O is 1.00 g/mL (or 1000 kg/m^)