Chemistry 211; Fullerton College; S. Nobles Name _____________________________
Pre-Lecture Assignment Spectroscopy B
Skills and Knowledge you should have:
• Knowledge of the electromagnetic spectrum.
• The relationship between wavelength, frequency, and energy of light.
• Be able to calculate the degrees of unsaturation.
Learning Objectives for Spectroscopy B
• Understand how bond strength influences IR absorption.
• Understand how atom size influences IR absorption.
• Understand how conjugation influences absorption.
• Understand how ring size influences absorption.
• Be able to identify absorptions of the functional groups.
• Be able to evaluate an IR and determine the functional groups and suggest a structure.
1. If you had IR spectra of two samples that were almost identical in the major functional group peaks, how would
you be able to differentiate their spectra?
2. True or False. The conjugation of a carbonyl group with a C=C bond will shift the absorption to a lower
wavenumber.
3. How could you use IR to differentiate between an aldehyde and a ketone?
4. Which will absorb at a higher wavenumber in IR, CH3COCH3 or CH3CH2OH?
5. True or False. C-H, O-H, and N-H bonds absorb at high frequency, > 2500 cm-1.
6. True or False. The higher the percent s character, the lower the wavenumber of an IR absorption.
