Question

Concentration A: 13 ppb

Concentration B: 2.9 x 10^-7 M

Express concentration B as ppb.

Express concentration of A as ppm

Concentrations of Iron

Answer 1

Concentration of A = 13 ppb

We have, 1000 ppb = 1 ppm

13 ppb = (1 x 13)/1000 ppm = 0.013 ppm

Concentration of B = 2.9 x 10^-7 M

i.e. 1000 mL of solution contains Fe = 2.9 x 10^-7 mol

Mass of Fe = 55.85 g/mol

Mass of Fe in 2.9 x 10^-7 mol of Fe = 2.9 x 10^-7 x 55.85 g = 161.965 x 10^-7 g = 161.965 x 10^-7 x 1000 mg = 161.965 x 10^-4 mg = 0.0162 mg

Therefore, there is 0.0162 mg in 1000 mL of solution and hence the concentration is in ppm is 0.0162 ppm

Now 1 ppm = 1000 ppb

Therefore, 0.0162 ppm = 16.2 ppb

Concentration of B in ppb is 16.2 ppb.