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Topic: Combustion  (Read 220 times)

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Offline Gio_5

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Combustion
« on: September 07, 2019, 04:12:47 AM »
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.

Offline Borek

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Re: Combustion
« Reply #1 on: September 07, 2019, 04:24:37 AM »
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.
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Offline Gio_5

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Re: Combustion
« Reply #2 on: September 07, 2019, 04:37:18 AM »
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"?

Offline Borek

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Re: Combustion
« Reply #3 on: September 07, 2019, 12:22:02 PM »
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?
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