Question

A sample of 0.892 g of potassium chloride (KCl) is dissolved in 54.6 g of water. What is the percent by mass of KCl in this solution?
Calculate the percent by volume of 20 mL of alcohol diluted in water to produce 250mL solution.

Answer 1

1) $$$Cm (KCl)=\frac{m(solute)}{m(solute)+m(solvent)}⋅100$

$$$Cm (KCl)=\frac{0.892}{0.892+54.6}⋅100 = 1.6 percent$

2) $Cv =\frac{v(solute)}{v(solute)+v(solvent)}⋅100$

$Cv (alcohol)=\frac{20}{20+250}⋅100=7.4 percent$