Parts Per Million (ppm) Concentration CalculationsWrite an equation representing the ppm concentration: ppm = mass solute (mg) -- volume solution (L)Extract the data from the question: mass solute (NaCl) = 0.0045 g. ... Convert the mass in grams to a mass in milligrams: mass NaCl = 0.0045 g = 0.0045 g -- 1000 mg/g = 4.5 mg.More items...read more >>