[andyman20]

when burning octane, there has to be excess amount of oxygen to get a complete combustion but if there isnt, the equation comes out to be

C8H18 + 20 O2 --> 4 CO2 + 3 CO2 + C + 9 H20

but i dont know how it comes to this..
is it one of the equations that you just have to memorise or is there a reason?
please help me as soon as possible please.

Thank you...

[xiankai]

the problem is that u got the equation wrong.

incomplete combustion yields some carbon monoxide in addition to the usual products of CO2 and steam.

C is not an end product of the reaction, and i wonder why u split CO2 into 4 and 3 moles seperately. am i to suppose there was a mistake and actually meant to be CO?

also, your equation is grossly wrong in terms of balancing. make sure no atoms are gained or lost.

[Donaldson Tan]

1. hydrocarbon + O2 -> CO2 + water
2. hydrocarbon + O2 -> CO   + water

when there is complete combustion, only reaction (1) occurs.

when there is incomplete combustion, both reactions (1) & (2) occur.