Answer
Mass percentage of C = 91.3 %
Mass percentage of H = 8.7 %
Work Step by Step
Strategy: To calculate the mass percentage of elements in the compound : 1- calculate the Molar mass of the compound 2- Calculate the mass of each element to the Molar mass and express this in percentage.
Toluene chemical formula, based on the figure : $C_{7}H_{8}$
Molar mass $C_{7}H_{8}$ = 7 x 12.0 + 8 x 1.00
Molar mass $C_{7}H_{8}$ = 92 g/mol
Mass percentage of C = $\frac{mass_(7 mole C)}{Molar mass_(C_{7}H_{8})}$$\times$ 100%
Mass percentage of C = $\frac{7\times12.0}{92.0}$$\times$ 100%
Mass percentage of C = 91.3 %
Mass percentage of H = $\frac{mass_(8 mole H)}{Molar mass_(C_{7}H_{8})}$$\times$ 100%
Mass percentage of H = $\frac{8\times1.00}{92.0}$$\times$ 100%
Mass percentage of H = 8.7 %
