Question

Xylene, an organic compound that is a major component of many gasoline blends, contains carbon and hydrogen only. Complete combustion of a 17.12 mg sample of xylene in oxygen yielded 56.77 mg of CO2 and 14.53 mg of H2O. Determine the empirical and molecular formula of xylene. Molecular weight of xylene is 106.16 g/mol

Answer 1

Xylene moles $=\frac{17.12}{106.16×1000}=0.00016moles$

Moles of $CO_2 =\frac{56.77}{44.01×1000}=0.0013$

Moles of $H_2O= =\frac{14.53}{18.02×1000}=0.0008$

Moles ratios

$\frac{0.0013}{0.0008}=1.625$

$\frac{0.0008}{0.0008}=1$

Hence molecular fomula

The empirical formula is C ₄H ₅.

The molecular formula C₈H₁₀