Question

What is the concentration of agcl in an aqueous solution that contains 1.2 x 10-3 gram of agcl in 800. grams of the solution? 1.2 ppm 1.5 ppm 7.2 ppm 9.6 ppm?

Answer 1

Concentration can be measured in ppm. ppm means parts mer million. In terms of mass , ppm units are mg/kg. 
concentration of AgCl solution is the mass of AgCl solute in mg per 1 kg of solution. 
mass of AgCl present = 1.2 x 10⁻³ kg = 1.2 mg
mass of solution = 800 g = 0.800 kg
the mass of AgCl in 0.800 kg of solution  = 1.2 mg
therefore mass of AgCl in 1 kg of solution = 1.2 mg / 0.800 kg x 1 kg = 1.5 mg
concentration of AgCl is 1.5 mg/kg
since mg/kg = ppm 
concentration of AgCl = 1.5 ppm
answer is 1.5 ppm