A gaseous compound is composed of $85.7 \%$ by mass of carbon and $14.3 \%$ by mass of hydrogen. Its

Question

A gaseous compound is composed of $85.7 \%$ by mass of carbon and $14.3 \%$ by mass of hydrogen. Its density $95 \mathrm{gL}^{-1}$ at 350 K and 1.0 atm pressure. Calculate the molecular formula of the compound.

Professor PC Thomas Classes · Answer

$\begin{aligned} & C \quad 85.7 \% \quad \frac{85.7}{12}=7.14 \quad 1 \ & H \quad 14.3 \% \quad \frac{14.3}{1}=14.3 \quad 2 \ & \mathrm{CH}_2(	ext { Empirical Eormula) } \ & 	ext { Empirical mass }=14 \mathrm{~g} / \mathrm{mol} \ & 	ext { density of gas }=\frac{P M}{R T} \ & M=\frac{d R T}{P}=\frac{1.95 	imes 0.0821 	imes 350}{1} \ & M=56 \mathrm{~g} / \mathrm{mol}\end{aligned}$