[jackfiore]

Hi there! I was just wondering what the general order (i.e. for molecules with the same number of carbon atoms) was in terms of flammability and flame colour was for alcohols, alkanes, and alkenes? I know that alcohols burn best because they already have oxygen present in them, and that alkenes burn with a more sooty flame than alkanes because they have a higher carbon percentage, but what are the general colours of the flames for them if you were to burn them, and which is the easiest to burn of them all and why?
Thanks a lot in advance

[Nobby]

It is a matter of oxygen what is present and how much hydrogen the molecule contains. In air it is abaut 21% oxygen. If the molecule contains not much hydrogen, then the combustion is not 100%. A lot of carbon goes as carbon black into the flame which gives the yellow illumination. Often also traces of sodium support it.

If a combustion takes place in an 100% oxygen atmosphere then there will be not much difference.