A sample of methane gas $($CH$4)$ having a volume of $2\mathrm{.}80$ L at T $=25\mathrm{.}0\backslash$deg C and PCH$4=1\mathrm{.}65$ atm is added to a $35\mathrm{.}0-$L reactor filled with oxygen $($O$2)$ at T $=25\mathrm{.}0\backslash$deg C and P $=1\mathrm{.}25$ atm.

a$)$ Calculate the partial pressure of CH$4$ and O$2$ in the $35\mathrm{.}0-$L reactor $($T $=25\mathrm{.}0\backslash$deg C$).$

The mixture is then ignited to form carbon dioxide $($CO$2)$ and water $($H$2$O$),$ and the temperature in the reactor is stable at $110\mathrm{.}0\backslash$deg C$.$

b$)$ Write down the chemical reaction of combustion

c$)$ Find the partial pressure of CO$2,$ H$2$O and O$2$ in the $35\mathrm{.}0-$L reactor.