Ok, sorry for that, i'm new around here. So, i got CH4+2O2 ->CO2 +2H2O,
PV=nRT 745.0,25=n.62,3.(273+25)
186,25/18565= 0,010 moles CH4
and for O2
757.0,3=n.62,3.(273+70)
n= 0,01 moles O2
So for molar fraction i got nO2=0,01/0,01+0,01 =0,5
and nCh4=0,01/0,01+0,01= 0,5
But i have absolutely no idea on how to do the "B"
i think its missing info on the temperature