Question

how many parts per million of mercury are there in a sample of tap water with a.mass of 750 g containing 2.2 mg of hg

Answer 1

Parts Per Million is defined as the number of parts of a solute per one million parts of a solution.

ppm = (Weight of Solute / Weight of Solution) × 10⁶

Data Given;
Weight of Solute (Hg) = 2.2 mg = 0.0022 g

Weight of Solution (Tap Water) = 750 g

Putting Values,

ppm = (0.0022 g / 750 g) × 10⁶

ppm = 2.93 × 10⁻⁶ × 10⁶

ppm = 2.93

Result:
It means if given tap water is containing 1 million particles then 2.93 particles in that are of Hg.