Question

1. a concentration of 13.5 ppm of mercury is found in a body of water with a mass of 150.8 kg. what mass of mercury is dissolved in the water?

Explanation:

Step1: Convert ppm to mass ratio

ppm (parts per million) means grams of solute per million grams of solution. So, \(13.5\) ppm \(=\frac{13.5\ g}{10^{6}\ g}\)

Step2: Calculate the mass of mercury

Given the mass of the water (solution) \(m = 150.8\ kg=150800\ g\)
Let the mass of mercury be \(x\)
Using the ratio \(\frac{x}{150800}=\frac{13.5}{10^{6}}\)

$$x=\frac{13.5\times150800}{10^{6}}$$

$$x=\frac{2035800}{10^{6}} = 2.0358\ g\approx2.04\ g$$

Answer:

\(2.04\ g\)