A 400-g sample of water contains 4.50 x 10-5 g of arsenic. Calculate the concentration of arsenic in the water sample in in parts per million

Answer 1

To calculate the concentration of arsenic in the water sample in parts per million (ppm), we first need to convert the mass of arsenic into milligrams.

1 g = 1000 mg

So, 4.50 x 10^-5 g = 4.50 x 10^-2 mg

Next, we divide the mass of arsenic by the total mass of the water sample:

Concentration of arsenic = (4.50 x 10^-2 mg / 400 g) x 10^6

= (0.0001125 mg / 400 g) x 10^6

= 0.00000028125 x 10^6

= 0.28125 ppm

Therefore, the concentration of arsenic in the water sample is 0.28125 ppm.