Mass spectroscopy practice questions

1. Assume that you have two unlabeled samples, one of methylcyclohexane and the other of

ethylcyclopentane. How could you use mass spectrometry to tell them apart?

2. Two mass spectra are shown below. One spectrum is that of 2-methyl-2-pentene; the other is of

2-hexene. Determine the structure of each spectrum. Explain.

3. 2-Methylpentane (C6H14) has the mass spectrum shown. Which peak represents M? Which is the

base peak? Propose structures for fragment ions of m/z 71, 57, 43, and 29. Why does the base

peak have the mass it does?

4. Identify the compound from the mass spectrum based on the given compounds below.

CH3 CH3

CH3

OHCH3

O

CH4

CH3 CH3 CH3 CH3

O

OH2

NH3

CH3

CH3