Incomplete Combustion Reaction

[joshua_quinn_1C]

During the lecture today about Balancing Chemical Reactions, Dr. Lavelle used the term "incomplete combustion reaction" when discussing the example about balancing the chemical equation of the combustion of butane. The chemical equation ended up being 2C4H10 + 13O2 --> 8CO2 + 10H2O. However, I am still confused on what an incomplete combustion reaction is and how it applies here in this example. Can someone expand on this? Thanks!

[Bryan Cheng 1H]

Complete combustion is when an organic molecule, usually an alkane or carbohydrate in 14A, reacts with water to yield only carbon dioxide and water. Incomplete combustion is when the reaction yields something other than only CO2 and water (such as soot/carbon allotropes or carbon monoxide). This could be if oxygen and the fuel are not present in the proper ratios (if the reaction isn't balanced in reality, basically).

[cnyland]

Hi!
I don't think this concept is something he expects us to fully understand right now, but it has to do with the amount of oxygen present in the reaction. In a complete combustion reaction, there is sufficient oxygen present to fully produce the CO2 and H2O. However, in an incomplete combustion reaction there is an insufficient oxygen supply so instead of producing carbon dioxide, carbon monoxide or carbon may be emitted. Additionally, I am confused as to how this relates to the problem in class because we did successfully balance the chemical reaction without a mention of CO or C in the products as may occur with an incomplete combustion reaction.
Hope this helped slightly!

[Meagan Kimbrell 1I]

Complete combustion occurs when enough oxygen is present, producing carbon dioxide (CO2) and water (H2O) as a result. On the other hand, incomplete combustion is when there is NOT enough oxygen available. Thus, the reaction is only able to form carbon monoxide (CO) and carbon (C). A good example is the burning of paper, which results in soot.

[Chris Oh 2I]

Complete combustion occurs when enough oxygen is present, producing carbon dioxide (CO2) and water (H2O) as a result. On the other hand, incomplete combustion is when there is NOT enough oxygen available. Thus, the reaction is only able to form carbon monoxide (CO) and carbon (C). A good example is the burning of paper, which results in soot.

What happens to the hydrogen in incomplete combustion if the only products are carbon monoxide and carbon? Is it released as H2 gas?

[Meagan Kimbrell 1I]

That's a good question!!! I believe that it still produces H2O as a result!! I tried searching it up and I saw examples of incomplete combustion that looked like this:
C3H8 + 2O2 → 3C + 4H2O, which still formed water as a result but not any carbon dioxide.

[Chris Oh 2I]

That's a good question!!! I believe that it still produces H2O as a result!! I tried searching it up and I saw examples of incomplete combustion that looked like this:
C3H8 + 2O2 → 3C + 4H2O, which still formed water as a result but not any carbon dioxide.

I see, I see! That makes a lot more sense now. Thanks for showing the balanced equation as well!