1. CyclohexanePuckered 109.5 o <‘s More H SaturatedBenzeneFlat 120 o <‘s Fewer H Unsaturated 20.8 Aromatic Hydrocarbons - 6 carbon ring w/double bonds -”benzene ring” - smell nice (cinnamon and vanilla) -different than cyclo- hydrocarbons

2. Figure 20.8: Two Lewis structures for the benzene ring.

3. Figure 20.8: Shorthand notation for benzene rings.

4. Figure 20.9: The bonding in the benzene ring is a combination of different Lewis structures.

5. Figure 20.10: Names of some common monosubstituted benzenes.

6. 20.10 Functional Groups  Hydrocarbon derivatives = primarily HC’s but have additional atoms or groups of atoms called functional groups. A functional group is a reactive portion of a molecule that undergoes predictable reactions.

7. Common functional groups  alcohols  ethers  aldehydes  ketones  carboxylic acids  esters

8. alcohol  hydroxyl group (-OH) Some examples are methanolethanol2-propanol Methanol = gasoline Ethanol = alcohol beverage Isopropyl = rubbing alcohol

9. ether  oxygen “bridge” An example is diethyl ether (This is the most common ether, often called simply ether, used as an anesthetic.)

10. carboxylic acid  carboxyl group, -COOH An example is ethanoic acid

11. ester  compound formed from a carboxylic acid, RCOOH, and an alcohol, R’OH. The general structure is

12. aldehyde  carbonyl group (C=O) with at least one H atom. An example is ethanal

13. ketone  carbonyl group with two hydrocarbon An example is 2-butanone