Chapter 18 · Organic Chemistry
18.1What Do I Smell?
7 min · two checks
Predict
Why can two molecules with similar formulas smell completely different?
The idea
- Define organic chemistry as the chemistry of carbon compounds.
- Connect odor to structure, not to the element carbon alone.
A huge share of the molecules you can smell — vanilla, vinegar, gasoline, orange peel — are carbon compounds. Carbon is good at this because it forms four bonds, chains and rings of almost any length, and stable attachments to H, O, N, and the halogens. Organic chemistry is that subject. It is not “chemicals from organs” only, and it is not opposed to inorganic chemistry as natural versus fake.
The smell of a molecule is a structural fact. Limonene and related hydrocarbons smell like citrus; small esters often smell fruity; amines can smell fishy. You will learn to read a structure as a skeleton plus functional groups. By the end of the chapter a formula like CH₃COOH should mean “carboxylic acid, sour, related to vinegar,” not just a string of letters.
Keep these
- Organic chemistry is the chemistry of carbon compounds.
- Carbon’s four bonds let it build chains, branches, and rings.
- Odor and behavior follow structure and functional groups.