Answer:
See below, please
Step-by-step explanation:
Because the mole ratio
Now, at the beginning
Mole m(CH4) =4 mol, m(O2) = 5 mol
If O2 gas is fully reacted, used up,
Need m(CH4) = 2.5 mol
Hence, the mole of CH4 left
m(CH4) = 4-2.5=1.5 mol
That means
At the end of the reaction,
m(CH4) =1.5 mol
m(O2) = 0 mol