# Calculate the mass of KCl that should be dissolved to form a 5 ppm Cl^- ion solution having a total volume of 20 dm^3?

Jul 17, 2015

The mass of KCl is 0.2 g.

#### Explanation:

$\text{5 ppm}$ means $\text{5 g of solute}$ in ${10}^{6} \text{g of solution}$.

$\text{Mass of soln" = 20 cancel("dm³ soln") × "1000 g soln"/(1 cancel("dm³ soln")) = "20 000 g soln}$

${\text{Mass of Cl"^(-) = 20 000 cancel("g soln") × ("5 g Cl"^-)/(10^6 cancel("g soln")) = "0.10 g Cl}}^{-}$

$\text{Mass of KCl" = 0.10 cancel("g Cl⁻")× "74.55 g KCl"/(35.45cancel("g Cl⁻")) = "0.2 g KCl}$