Combustion of alkenes - Higher tier
alkene Unsaturated hydrocarbon containing at least one C=C and with the general formula CnH2n combust, but they are less likely than alkanes to combust completely.
Complete combustion of alkenes produces carbon dioxide and water, provided there is a plentiful supply of oxygen.
Incomplete combustion of alkenes occurs where oxygen is limited and produces water, carbon monoxide and carbon (soot). This causes a smoky flame.
Functional group
Alkenes have a functional group C=C – the part of the molecule that takes part in reactions. Alkanes, in contrast, do not have a functional group and are less reactive as a result.
Complete combustion of alkenes produces carbon dioxide and water, provided there is a plentiful supply of oxygen.
Here are the equations for the complete combustion of propene:
Propene + oxygen \(\rightarrow\) carbon dioxide + water
C3H6 + 4 \(\frac{1}{2}\) O2 \(\rightarrow\) 3CO2 + 3H20