Question

Percent by mass to parts per million. Convert 4.45% NaOH(aq) solution to parts per million NaOH in the solution. Do NOT assume a dilute aqueous solution! Use the molar mass of the entire salt formula, not either ion alone. The solution density is 1.047 g/mL. Answer to 3 significant figures with appropriate units.

Answer 1

4.45% NaOH solution means 4.45 g of NaOH present in 100 g of solution

Given density of solution is d = 1.047 g/mL

So 1.047 g of solution has a volume of 1mL

    100 g of solution has a volume of (100g*1mL)/1.047g = 95.5mL

                                                                                 = 95.5 mL*10-3L/mL

                                                                                 = 0.0955 L

So the concentration is 4.45g *1000 mg/g = 4450 mg/0.0955L

                                                             = 46597 mg/L

                                                             = 46597 ppm        Since 1 ppm = 1 mg/L