Question

the mole fraction of benzene is a solution with toluene is 0.50.calculate the weight percent of benzene in the solution?

Answer 1

Answer: $45.88 \%$

Explanation: mole fraction of benzene = 0.50

mole fraction of benzene + mole fraction of toluene = 1

mole fraction of toluene = 1 - mole fraction of benzene = 1-0.50= 0.50

${\text {Mass} ={\text{moles}}\times {\text{Molar mass}}$

${\text {Mass of benzene} =0.50\times {78g/mol}=39g$

${\text {Mass of toluene} =0.50\times {92g/mol}=46g$

Thus weight percentage of substance=$\frac{\text {mass of the substance}}{\text {total mass of the substance}}\times 100 \%$

Thus${\text {weight percentage of benzene}}=\frac{39g}{85g}\times 100 \%=45.88 \%$