CHEM 121 glossary
Functional group
A specific group of atoms in a molecule, usually containing a heteroatom or a multiple bond, that gives a whole family of compounds its characteristic reactions. Examples: –OH (alcohol), C=O (aldehyde, ketone), –COOH (carboxylic acid), –COO– (ester), –NH₂ (amine).
Acetic acid: the –COOH (carboxylic acid) group.
Example
Acetic acid, , has a carboxylic acid group. A condensation polymer needs monomers with two functional groups each, such as a diacid and a diol, which link into a polyester and release water.