KETONES (slides 1 and 2) Whenever you see a double-bonded C=O group (called a carbonyl) on any carbon except the end carbons of an organic compound, you have a ketone group. Ketones will be your best friend in organic chemistry second semester! CARBOXYLIC ACIDS (slides 3 and 4) When you see a carboxylic acid group (-COOH), you have (surprise) a carboxylic acid. These groups are acidic (second surprise), and are related to the ketone group and aldehyde group. These groups only occur at the ends of carbon chains. Any thoughts on why?