The IR spectrum of a sample contains absorptions at 3050, 2950, and 1620 cm-1. To what class of organic compound does this sample most likely belong

Alkene

Explanation:

The IR spectrum of an organic compound shows us the functional groups present in the compound.

By looking at the various stretching frequencies given in wave numbers, we can decide what functional groups are in the compound and hence the class of organic compounds to which it belongs.

The stretch 3080 cm-1 shows a mono-substituted alkene

The stretch 2950 cm-1 shows a C-H bond

The stretch 1620 cm-1 shows an alkenyl stretch.

Hence the compound is an alkene.