What is this concentration in ppm?

Question

(Assume that the density of the solution is 1.00 g/mL.)

What is this concentration in ppm for a solution of As₂O₃ that has a molarity of 6×10^-7 M.

Answer 1

ppm can also be equated to mg per L = mg/L

This can be seen as 0.001 g / 1000 g (given a density of 1 g/ml for water)

So, we will simply convert 6x10^-7 mol/L into mg / L which will give us ppm

6x10^-7 mol/L As2O3 x 197.8 g/mol = 1.19x10^-4 g / L

1.19x10^-4 g / L x 1000 mg / g = 1.19x10^-1 mg/L = 0.119 mg/L = 0.119 ppm