Chapter 18 · Organic Chemistry
18.11Functional Groups
9 min · two checks
Predict
What is a functional group?
The idea
- Define functional group.
- Match the common groups to their family names.
Hydrocarbons are the blank scaffolding. Functional groups are the features that do chemistry. An alcohol has –OH on a carbon. An ether has C–O–C. An aldehyde has a carbonyl (C=O) at the end of a chain; a ketone has a carbonyl between carbons. A carboxylic acid has –COOH. An ester has –COO– linking two chains. An amine has nitrogen with a lone pair, bonded to carbon. A haloalkane has F, Cl, Br, or I in place of H.
Members of one family behave alike. All small alcohols dissolve better in water than the parent alkane does, and they can be oxidized in similar ways. All carboxylic acids are weak acids. When you meet a new structure, circle the functional group before you do anything else. The chain length changes the boiling point and the solubility. The group decides the reaction.
Keep these
- A functional group is a recurring reactive cluster.
- Family names: alcohol, ether, aldehyde, ketone, acid, ester, amine.
- The group predicts the reaction. The chain modulates physical properties.