Fuel does not exist as a pure substance
varying hydrocarbon chains
Jet and diesel fuel contain hydrocarbon chains of 12 to 20 carbons in length. Fuel oil contains hydrocarbons 20 to 40 carbons long.
sulfur (S)
nitrogen (N)
oxygen (O)
The combustion process is NEVER complete and NEVER ideal. You will always get more than just CO2 and H2O