Problem $2$: The average composition of natural gas in the US is approximately $94$mol$\%$ methane, $4\%$ ethane and $2\%$ N$2$ There are also other trace compounds,

but those have significantly less impact than methane. Natural gas is often burned with excess air

in a home furnace. The furnace is not well maintained and the product gases contain some

undesired $CO,$ at a ratio of $CO$:$C{O}_2$ ratio of $1$:$5.$ All of the combustible materials in the natural

gas, and $90\%$ of oxygen in the air, are converted into products. Calculate the composition of the

product gases.