Question

A sample of hard water is found to contain 50 mg of CaSO₄ in 12 kg of the sample. Calculate the hardness of the sample in terms of ppm of CaSO₄.

Answer 1

Given: Mass of CaSO₄ = 50 mg

Mass of water sample = 12 kg = 12,000 g

We are to find the hardness in ppm (parts per million) due to CaSO₄.

ppm = `"Mass of solute (mg)"/"Mass of solution (g)" xx 10^6`

ppm = `50/12000 xx 10^6`

= 4.1667 × 10³

= 4166.7 ppm

∴ The hardness of the sample is 4166.7 ppm.