Question

What is the mass of arsenic that is contained in a 50.0 g sample if the concentration is 5 ppm?

Answer 1

Answer: The mass of arsenic found in the sample is 0.25 mg

Explanation:

ppm is the amount of solute (in milligrams) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of oxygen in sea water, we use the equation:

$\text{ppm}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^6$

Both the masses are in grams.

We are given:

Concentration of arsenic = 5 ppm

Mass of sample = 50 g

Putting values in above equation, we get:

$5=\frac{\text{Mass of arsenic}}{50g}\times 10^6\\\\\text{Mass of arsenic}=\frac{5\times 50}{10^6}=0.00025g=0.25mg$

Conversion factor used:  1 g = 1000 mg

Hence, the mass of arsenic found in the sample is 0.25 mg