Answer
(e) $0.825$
Work Step by Step
The molar masses are: $$\begin{aligned}
M_{N_2}&=28\text{ kg/kmol}\\
M_{CO_2}&=44\text{ kg/kmol}.
\end{aligned}$$ The mass of each component is: $$\begin{aligned}
m_{N_2}&=2\cdot 28=56\text{ kg}\\
m_{CO_2}&=6\cdot 44=264\text{ kg}.
\end{aligned}$$ The total mass of mixture: $$m_{total}=56+264=320\text{ kg.}$$ The mass fraction of $CO_2$ is $$w_{CO_2}=\frac{m_{CO_2}}{m_{total}}=\frac{264}{320}=0.825.$$
The correct answer is (e) $0.825$.
