Express the concentration of a 0.0320 M aqueous solution of fluoride, F−, in mass percentage and in parts per million (ppm). Assume the density of the solution is 1.00 g/mL.

607 ppm

Explanation:

In this case we can start with the ppm formula:

If we have a solution of 0.0320 M, we can say that in 1 L we have 0.032 mol of , because the molarity formula is:

In other words:

If we use the atomic mass of  (19 g/mol) we can convert from mol to g:

Now we can convert from g to mg (1 g= 1000 mg), so:

Finally we can divide by 1 L to find the ppm:

We will have a concentration of 607 ppm.

I hope it helps!