11.1: Exercises

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Assign one of the structures A – J presented on page 2 to each of the IR spectra provided (1 – 10). Base your assignment on one or more key frequencies, according to guidelines presented in the recitation notes and on p. A19–A31 of your textbook. Especially useful are p. A19 and A20. For each spectrum do the following:

1. Mark key absorption frequencies in the spectrum, and associate each with a specific bond (e.g. O–H, C=O). Keep in mind that there are usually only one or two key bands in each spectrum, although in some cases you might observe up to three. Do not label the alkane C–H stretch, since these bands are present in most organic compounds.

2. Assign a letter from the structures given (A – J). There is only one structure per spectrum.

3. Identify the main functional group present in the structure (i.e. ketone, alcohol, etc.).

4. Provide approximate frequency values for the bands you labeled in the spectrum (in cm^–1), and identify their shape (broad, medium, or narrow) and intensity (weak, medium, or strong). Each of the above items is worth 2.5 points, for a total of 10 points per question.

Each of the above items is worth 2.5 points, for a total of 10 points per question.

Key Bands

Bond: O-H	Approximate frequency: 3000	Shape: broad	Intensity: strong
Bond: C=O	Approximate frequency: 1700	Shape: medium	Intensity: strong

INCOMPLETE OR UNCLEAR ANSWERS WILL RECEIVE NO CREDIT

STRUCTURES

KEY BANDS

Bond: _______	Approximate frequency: _______	Shape: ________	Intensity: ________
Bond: _______	Approximate frequency: _______	Shape: ________	Intensity: ________
Bond: _______	Approximate frequency: _______	Shape: ________	Intensity: ________

GRADE: ___________

KEY BANDS:

Bond: __________	Approximate frequency: _________	Shape: _____________	Intensity: ___________
Bond: __________	Approximate frequency: _________	Shape: _____________	Intensity: ___________
Bond: __________	Approximate frequency: _________	Shape: _____________	Intensity: ___________

GRADE: ___________

KEY BANDS:

Bond: _________	Approximate frequency: ________	Shape: _________	Intensity: _________
Bond: _________	Approximate frequency: ________	Shape: _________	Intensity: _________
Bond: _________	Approximate frequency: ________	Shape: _________	Intensity: _________

GRADE: _______

KEY BANDS:

Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________

GRADE: _________

KEY BANDS:

Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________

GRADE: _________

KEY BANDS:

Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________

GRADE: _________

KEY BANDS:

Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________

GRADE: _________

KEY BANDS:

Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________

GRADE: _________

KEY BANDS:

Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________

GRADE: _________

KEY BANDS:

Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________
Bond: _________	Approximate frequency: _______	Shape: __________	Intensity: ________

GRADE: _________