Unit Introduction

Unit 2 | Smells

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Each flower puts out a scent that attracts specific insects. Not all flowers smell pleasant. The corpse flower, which blooms once every three years, smells like decaying flesh.
© GEORGIOS KEFALAS/epa/Corbis

In this unit, you will learn

  • how atoms form molecules

  • to predict the smell of a compound

  • to interpret molecular models

  • how the nose detects different molecules

  • about amino acids and proteins

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Alex Cao/Getty Images

Why Smells?

The sense of smell is a familiar and important part of our lives. It helps us detect pleasant smells as well as unpleasant smells that alert us to possible dangers. Sometimes, our sense of smell helps us to detect things that we can’t see. Sometimes, we detect something all the way across the room or even in another room. But how does it work? The way atoms are connected in molecules, and the structures of the molecules, have a great deal to do with the properties of those molecules. When you understand the chemistry of molecules, you will begin to answer the question, “What is the chemistry of smell?”