1. Living By Chemistry SECOND EDITION
Unit 2: SMELLS
Molecular Structure and Properties

2. 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

3. Lesson 28: Sniffing Around
Molecular Formulas

4. ChemCatalyst
1. What do you think is happening when you smell something?
2. Why do you think we have a sense of smell?

5. Key Question
What does chemistry have to do with smell?

6. You will be able to:
detect patterns in chemical formulas and relate these patterns to a molecular property
create a hypothesis based on analysis of data

7. Prepare for the Activity
Molecular formula: The chemical formula of a molecular substance, showing the types of atoms in each molecule and the ratios of those atoms to one another.

8. Prepare for the Activity (cont.)
Chemicals may have very strong odors or be caustic. When smelling, don’t sniff directly from the container. Instead, use a wafting technique (use your hand to draw air toward you).
Work in groups of three or four students.

9. Discussion Notes
A possible hypothesis is “The smell of a substance can be predicted if you know its name and/or its chemical formula.”

10. Wrap Up What does chemistry have to do with smell?
Smell appears to be related to molecular formula and chemical name.

11. Check-In
How would you expect a compound with the molecular formula C8H16O2 to smell? Explain.
How sure are you of your prediction?