Organic chemisty

• A hydrocarbon compound that only contains carbon and hydrogen.
• A saturated hydrocarbon has single bonds only.
• An unsaturated hydrocarbon contains carbon-to-carbon multiple bonds like double or triple bonds.
• A homologous series is a family of compounds with similar chemical properties whose successive members differ by the addition of a $CH_2$ group.
• A functional group is the part of a molecule that is largely responsible for the molecule's chemical properties.