$n_{CH_4}=3,36/22,4=0,15mol$
$PTHH :$
$CH_4+2O_2\overset{t^o}\to CO_2+2H_2O$
a/Theo pt :
$n_{O_2}=2.n_{CH_4}=2.0,15=0,3mol$
$⇒V_{kk}=0,3.22,4.5=33,6l$
b/Theo pt :
$n_{CO_2}=n_{CH_4}=0,15mol⇒m_{CO_2}=6,6g$
$n_{H_2O}=2.n_{CH_4}=0,15.2=0,3g⇒m_{H_2O}=0,3.18=5,4g$