Question

why do hydrocarbon molecules with an odd number of carbon atoms have lower melting points than those with an even number of carbon atoms?

Answer 1

Answer:

Alkane molecules with odd numbers of carbon atoms have lower intermolecular attractions and correspondingly lower melting points because alkanes with an odd number of carbon atoms pack less tightly because the methyl groups at the ends of their chains can avoid those of another chain only by increasing the distance between their chains.

Answer 2

Answer:

Alkane molecules with odd numbers of carbon atoms have lower intermolecular attractions and correspondingly lower melting points because alkanes with an odd number of carbon atoms pack less tightly because the methyl groups at the ends of their chains can avoid those of another chain only by increasing the distance between their chains.