Current Attempt in Progress

A mixture of propane and butane is burned with pure oxygen. The combustion products contain $46\mathrm{.}7$mole$\%H_{2}O.$ After all the water is removed from the products, the residual gas contains $68\mathrm{.}8$mole$\%C{O}_2$ and the balance $O_2$

a$.$ What is the mole percent of propane in the fuel?

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b$.$ It now turns out that the fuel mixture may contain not only propane and butane but also other hydrocarbons. The fuel does not contain oxygen. However, the dry combustion gases still contain $68\mathrm{.}8\%$ carbon dioxide. We wish to determine the elemental composition $($carbon and hydrogen molar percentages$)$ of the fuel feed.

$($Hint: Calculate the elemental compositions on an oxygen free basis$).$ What is the mole of carbon in the fuel?

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