Why do Oxygenated fuels contain less energy than hydrocarbons?

[CurryBoy]

Homework Statement

Why do Oxygenated fuels contain less energy than hydrocarbons?
So my science teacher asked us this question and i have no clue what the answer is. We used a calorimeter to test the amount of energy in ethanol and octane, and the octane had more energy. Could anyone answer the question above? I would appreciate all the help i can get, thanks :)

Homework Equations

The Attempt at a Solution

Okay after doing some more research, I am guessing it has to do with the bonds in each fuel. Since hydrocarbons contain mostly carbon-carbon bonds, which are one of the strongest, they are very durable and hard to break. Unlike oxygenated fuels which are mixed with oxygen and have weaker bonds. Thus, the hydrocarbons are stronger due to the stronger bonds. Is that right? and does it make sense?

 

[Ygggdrasil]

This question is a very good question to ask students because it tests whether they understand combustion reactions. Here are a few things to think about as you answer:

1) In the combustion of hydrocarbons (oxygenated or not), what are the products and reactants?

2) A combustion reaction is a redox reaction. Which chemical species are being oxidized and which species are being reduced?

3) In redox reactions, what factors determine how much energy gets released by the reaction?