Alkanes: alkane + oxygen → carbon dioxide + water
Alkenes can also undergo combustion: alkene + oxygen → carbon dioxide + water
When alkenes combust, there is more soot (more carbon produced) due to higher carbon:hydrogen ratio in the molecules
Alkenes are more reactive so can undergo addition reactions (when the double bond breaks and allows the carbon to form a bond with another atom)
E.g. Alkenes and bromine water (bromine water goes from orange to colourless as it reacts)
The product above is named 1,2-dibromoethane as the bromines are added to carbons numbers 1 and 2 and the result is a molecule with 2 bromines attached to an ethane molecule
Alkanes can also react with bromine water if exposed to UV light, so the bromine water goes from orange to colourless.
The reaction bellow (if you pretend the chlorines are bromines) forms bromomethane and hydrogen bromide
That is all for this post!