[Gio_5]

Hello everyone,
I would like a helping hand for this exercise:

"A mixture of carbon monoxide, methane and nitrogen occupies a volume of 40 mL. Burning this mixture with an excess of oxygen, a volume concentration of 42 mL is observed after cooling at room temperature and together the formation of 36 mL of dioxide of carbon. Determine the volume of each component of the mixture. "

The first doubt is the reaction, I believe it is the following: CO + CH₄ + N₂ + O₂ -> CO₂ + N₂ + H₂O. But is impossible to balance.
Then I don't know how to proceed, because I don't have anything apart from the volumes and the molecular weights.
I also didn't understand if CO₂ is part of those 42 mL or less.
Please enlighten me, thanks.

[Borek]

There are no single combustion reactions for mixtures. Each combustible reacts separately, following its own balanced reaction.

Sometimes people do write equations for mixtures (burning of black powder comes to mind) to make calculations easier, but these are not real reaction equations, as they are not properly balanced. For practical stoichiometry calculations they do behave as one though.

[Gio_5]

Ok, so the single reaction are:
CH₄ + 2O₂ -> CO₂ + 2H₂O
2CO + O₂ -> 2CO₂
N₂ -> N₂
I think.
Now, how do I "Determine the volume of each component of the mixture"?

[Borek]

a volume concentration of 42 mL is observed

No idea what this is intended to mean.

If there were 36 mL of CO₂ produced, what was the initial volume of CO and CH₄? (Hint: what is volume of CO₂ produced by the combustion of 1 mL of CO? by the combustion of 1 mL of CH₄?