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

2. Lesson 47: Mirror, Mirror
Mirror-Image Isomers

3. ChemCatalyst
Which of these objects looks identical in a mirror? Explain any differences.
1. glove 2. barbell
3. spring tetrahedron

4. Key Question
What are mirror-image isomers?

5. You will be able to: recognize mirror-image molecular structures
explain what it means for molecules to be superimposable
understand why mirror-image isomers have different properties

6. Prepare for the Activity
Work in groups of four.

7. Discussion Notes
Mirror-image molecules that cannot be superimposed on each other are called mirror-image isomers.
Tetrahedral molecules in which four different atoms or groups are attached to a carbon atom always have mirror-image isomers.

8. Discussion Notes (cont.)
The mirror-image isomers D-carvone and L-carvone have different smells.
The mirror-image isomers have a “handedness.”

9. Wrap Up What are mirror-image isomers?
Molecules that are not identical to their mirror image are called mirror-image isomers.
Mirror-image isomers have a “handedness,” just like a right hand and a left hand.
Mirror-image isomers can have different properties, including smell.
Molecules that have at least one carbon atom with four different atoms or groups attached to it have a mirror-image isomer.

10. Check-In
Which of these molecules will have a mirror-image isomer? Explain your reasoning.
A. CF B. CHF3 C. C(CH3)4