Question

Express the concentration of a 0.0390 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

so,

So density doesn't matter

ppm = mg/L or Kg solution

Mass % = Mass of Solute/Mass of solution


again just come up with an amount of solution im going to use 1L

0.0390 M = x moles/1L

x = 0.0390Moles of F-

0.0390mol*18.998403g/mol = 0.7409g


PPM:

1mg = 1000g

0.7409g = 740.9mg

740.9mg/1L = 740.9mg



Mass Percent:

density 1g/mL

thus
1g = 1mL
thus
1L = 1kg
thus
1L = 1000g

so,
(0.7409g/1000g)*100
= 0.07409%_(m/m)