Molecular Diversity Arising from variation in carbon skeletons Chapter 3

Carbon Chains Carbon chains form the skeletons of most organic molecules. Hydrocarbons—Organic molecules consisting of only carbon and hydrogen. Hydrocarbons can undergo reactions that release a relatively large amount of energy.

(a) Length EthanePropane The skeletons vary in:

(b) Branching Butane2-Methylpropane (commonly called isobutane) The skeletons vary in:

(c) Double bonds 1-Butene2-Butene The skeletons vary in:

(d) Rings CyclohexaneBenzene The skeletons vary in:

The chemical groups most important to life The distinctive properties of an organic molecule depend not only on its carbon skeleton but also on the chemical groups attached to that skeleton. These chemical groups are known as functional groups.

1. Hydroxyl Group (—OH) Compound Name: Alcohol -The specific name usually ends in –ol Examples: Ethanol, the alcohol present in alcoholic beverages.

Ethanol

2. Carbonyl Group (>C=O) Compound Name: Ketone -Carbonyl group is with in a carbon skeleton Compound Name: Aldehyde -Carbonyl group is at the end. Examples: Acetone, the simplest ketone. Propanal, an aldehyde. R R

Propanal

3. Carboxyl Group (—COOH) Compound Name: Carboxylic acid or Organic acid Examples: Acetic acid, which gives vinegar its sour taste. R

Acetic Acid