Question

Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0011 % Pb by mass. How much of the water (in mL ) contains 165mg of Pb? (Assume a density of 1.0 g/ml.)

Answer 1

Use proportions:

(165/1000) g / 0.0011%
=0.165 g/0.000011
=15,000 mL

Answer 2

But when you write it up to submit it please include the units so the equations balance!