PLEASE CAN YOU ANSWER BOTH QUESTIONS STEP$-$BY$-$STEP WITH CLEAR REASONS OF WHAT YOU$$VE DONE. IM STRUGGLING WITH THESE TWO QUESTIONS. I BELIEVE THE TWO QUESTIONS ARE LINKED.

A fuel gas consists of $75\%$ butane $($C$4$H$10),10\%$ propane $($C$3$H$8)$ and $15\%$ butene $($C$4$H$8)$ by volume.

It is to be fed to the combustion chamber in $10\%$ excess air at $25$C$,$ where it is completely burnt to carbon dioxide and water. The flue gases produced are to be used to generate $5$ bar steam from water at $90$C$.$

With the aid of the data at the end of the question, steam tables and the enthalpy table given in the Appendix

$($e$)$ Determine the composition of the flue gases by volume $($assuming the inlet air is dry$)$ :

$($i$)$ on a wet basis

$($ii$)$ on a dry basis.

$($f$)$ Determine the $$furnace efficiency$$ if the flue gases leave the boiler at$300$C$.$

Net calorific value $($MJ m$3)$ at $25$C of:

Butane $($C$4$H$10)=111\mathrm{.}7$ MJ m$3$

Butene $($C$4$H$8)=105\mathrm{.}2$ MJ m$3$

Propane $($C$3$H$8)=85\mathrm{.}8$ MJ m$3$

Air is $21\%$ oxygen, $79\%$ nitrogen by volume and $23\mathrm{.}3\%$ oxygen and

$76\mathrm{.}7\%$ nitrogen by mass.

Atomic mass of C $=12,$ O $=16,$ N$=14$ and H $=1.$