Q. 9.93 - An Introduction to General, Organic, and Biological Chemistry

Question

Calculate the mass percent  $(m/m)$ of a solution containing  $15.5 \mathrm{g}\text{ of }{\mathrm{Na}}_2{\mathrm{SO}}_4\text{ and }75.5 \mathrm{g}\text{ of }{\mathrm{H}}_2\mathrm{O}. \left(9.4\right)$ $75.5 g of H_{2}O.(9.4)$

Step-by-Step Solution

Answer

The mass percent is$17.0\% (m/m)$.

Step 1: Introduction.

The quantity of an element or compound or a constituent in a mixture can be expressed in mass percentage.

Step 2: Given data.

Solution is $15.5 \mathrm{g}\text{ of }{\mathrm{Na}}_2{\mathrm{SO}}_4\text{ and }75.5 \mathrm{g}\text{ of }{\mathrm{H}}_2\mathrm{O}. \left(9.4\right)$ Want mass percent (%m/m) of $N{a}_{2}S{O}_4$

In the definition of mass percent, the mass in grammes of the solute and solution is used to determine the mass percent.

Factors of conversion/equalities,

$Mass percent (\%m/m)=\frac{Mass of solute}{mass ofsolute+ mass of solvent}\times 100$

$Mass percent (\%m/m)=\frac{grams of solute}{grams of solution}\times 100$

Step 3: Explanation.

The weight of the solute as well as the solution are calculated using the data.

$mass of solute=15.5 g N{a}_{2}S{O}_4$

$\frac{mass of solvent =+75.5 g H_{2}O}{mass of solution =91.0 g solution}$

$\text{ Mass percent }(\mathrm{\%}\mathrm{m}/\mathrm{m})=\frac{15.5 g \mathrm{Na}{\mathrm{Na}}_4}{91.0 \mathrm{g}\text{ solution }}\times 100$

$=17.0\% (m/m)$