Alkenes are hydrocarbons that contain at least one carbon-carbon double bond, distinguishing them from alkanes which have single bonds only. They are unsaturated, meaning they can react with other atoms to "saturate" the double bond.
Organic compounds made up of only hydrogen and carbon atoms.
Saturated compound: A hydrocarbon that contains only single bonds between carbon atoms, making no room for additional hydrogen atoms.
Addition reaction: A chemical reaction where atoms are added to a molecule without taking any away, common in reactions involving alkenes