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Tutorial: Combustion Reactions

What are the characteristics of combustion reactions?

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Watch the video to see what the equations for these types of combustion reactions look like.

You may want to use the study guide to follow along. If so, click below to download the study guide.


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For the last few types of chemical reactions, we have been able to use elements from all over the periodic table, but this next reaction type only involves three elements: carbon, hydrogen, and oxygen. We're familiar with combustion reactions in our every day life. Any fire is combustion reaction. Most cars have internal combustion engines, so their energy comes from just a series of combustion reactions.

Well, from the viewpoint of chemistry, a combustion reaction is a chemical reaction that occurs between a hydrocarbon and oxygen to produce carbon dioxide and water.

Now, this word hydrocarbon is new. A hydrocarbon is just a molecule made up of carbon and hydrogen, just like the name suggests. So we can express the chemical formula for hydrocarbons broadly using variables x and y. Butane is an example of a hydrocarbon, because it has the chemical formula C4H10.

An example of a combustion reaction would be C6H6 reacting with oxygen - and remember that because oxygen is a HONCLBRIF element, it has to be here as the diatomic O2 - to produce CO2, carbon dioxide, and H2O, water.

Now, you might notice that this chemical equation isn't balanced. The balanced chemical equation for this reaction is 2C6H6 plus 15O2 yields 12CO2 plus 6H2O.

You see these types of reactions every day, but now you know what's happening on a molecular level with combustion reactions


Let's Practice

Which one?

Which of the following would be a product of a combustion reaction?

a hydrocarbon
a salt
water

Which is a reactant in a combustion reaction?

water
carbon dioxide
oxygen

Which of these would be required for the combustion of gasoline \((\text{C}_{8}\text{H}_{10})\)?

oxygen
hydrocarbon
water

Which of these would be a product of the combustion of propane \((\text{C}_{3}\text{H}_{8})\)?

carbon dioxide
oxygen
hydrocarbon

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