Calculate the mass percentage of benzene \left(\mathrm{C}_{6} \mathrm{H}_{6}\right) and carbon tetrachloride \left(\mathrm{CCl}_{4}\right) if 22 \mathrm{~g} of benzene is dissolved in 122 \mathrm{~g} of carbon tetrachloride.
Calculate the mass percentage of benzene \left(\mathrm{C}_{6} \mathrm{H}_{6}\right) and carbon tetrachloride \left(\mathrm{CCl}_{4}\right) if 22 \mathrm{~g} of benzene is dissolved in 122 \mathrm{~g} of carbon tetrachloride.

Solution
Mass percentage of

    \[\begin{array}{l} C_{6} H_{6}=\frac{\text { Mass of } \mathrm{C}_{6} \mathrm{H}_{6}}{\text { Total mass of the solution }} \times 100 \% \\ =\frac{\text { Mass of } \mathrm{C}_{6} \mathrm{H}_{6}}{\text { Mass of } \mathrm{C}_{6} \mathrm{H}_{6}+\text { Mass of } \mathrm{CCl}_{4}} \times 100 \% \\ =\frac{22}{22+122} \times 100 \% \\ =15.28 \% \end{array}\]

Mass percentage of
C C l_{4}=\frac{\text { Mass of } \mathrm{CCl}_{4}}{\text { Total mass of the solution }} \times 100 \% =\frac{\text { Mass of } \mathrm{CCl}_{4}}{\text { Mass of } \mathrm{C}_{6} \mathrm{H}_{6}+\text { Mass of } \mathrm{CCl}_{4}} \times 100 \% =\frac{122}{22+122} \times 100 \% =84.72 \%
Alternatively,
Mass percentage of \mathrm{CCl} 4=(100-15.28)=84.72 \%