Question

Express the concentration of a 0.0190 M aqueous solution of fluoride, F–, in mass percentage and in parts per million. Assume the density of the solution is 1.00 g/mL.

Answer 1

0.0190 M = 0.0190 mol / L

                = ( 0.0190 mol / L ) ( 19 g / mol )

                = 0.361 g / L

                = 361 mg / L

                 = 361 ppm

1 ppm = 1 mg / L

in parts per million = 361 ppm

molarity = mass % x 10 x density / molar mass

0.0190 = mass % x 10 x 1.00 / 19

mass % = 0.0361 %

mass percentage = 0.0361 %