COncentration!!! omfg...i need help...can't solve problem...?

Question

If a 500L indoor air sample with a mass of 0.59kg contained, 3.2mg of formaldehyde, what would be the concentraction of formaldehyde in parts per million?

Answer 1

Covert both to g:

5.9 x 10squared g and 3.2 x 10-3 g.

Now you can solve it. Divide the smaller by the larger.