Question

A solution contains 15.3g of KCI dissolved in 175.0 g of water. Calculate the percent by mass concentration of the solution.

Answer 1

Percent by mass is defined as:

`\text{Percent by mass = }\frac{\text{Mass of solute}}{Mass\text{ of solution}}`

The solute will be KCl and the dissolvent will be water.

The solution is the sum of solute plus dissolvent. It means, we have to sum the mass of the solute plus the mass of dissolvent:

`\begin{gathered} \text{Percent by mass=}\frac{\text{ Mass of solute}}{Mass\text{ of solute + Mass of solution}}\text{ }*100 \\ \text{Percent by mass = }\frac{\text{15.3 g}}{15.3\text{ g + 175.0 g}}*100\text{ =8.04\%} \\ So,\text{ the percent by mass is 8.04\%} \end{gathered}`

The answer will be B. 8.04%