A gas mixture contains \(64\%\) methane and \(36\%\) ethane by mass. The density of the mixture at \(27^\circ\mathrm{C}\) and \(750\ \mathrm{mmHg}\) pressure (in \(\mathrm{g\,L^{-1}}\)) is
\[
(\text{At. wt. of C}=12,\; \text{H}=1,\; R=0.082\ \mathrm{L\,atm\,K^{-1}\,mol^{-1}})
\]