What is the concentration expressed in ppm of a solution containing 0.036 g of sodium chloride (58.44g/mol) in 0.500 Liters of solution ? Assume the density of the solution to be 1.00g/mL.

Question

What is the concentration expressed in ppm of a solution containing 0.036 g of sodium chloride (58.44g/mol) in 0.500 Liters of solution ? Assume the density of the solution to be 1.00g/mL.

Answer 1

ppm is actually the same as mg/liter, i.e. milligrams per liter*. So, all we have to do is to convert0.036 g to mg.

0.036 g x 1000 mg/g = 36 mg.

So, the solution has 36 mg in 0.500 liters. This is the same as 72 mg in 1 liter = ppm

So, the answer would be there are 72 ppm NaCl.

(NOTE: we do not need to use the molar mass of 58.44 g/mol in this calculation)

*With a density of 1.00 g/ml, 1 liter (1000 ml) would be = 1000 g

1 mg is = 0.001 g

So 1 mg per liter = 0.001 g/1000 g = 10^-3/10³ = 10^-6 = 1 millionth so 1 mg/L = 1 ppm