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
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.