Explain how weak intermolecular forces and covalent bonds contribute to the properties of small molecular substances.

Small molecular substances have low melting and boiling points because the weak intermolecular forces between the molecules are easily overcome during state changes. In contrast, the covalent bonds within the molecules are much stronger and are not broken when these substances melt or boil.

This answer effectively distinguishes between the types of forces involved and relates them to the observable properties of small molecular substances, testing the student's understanding of intermolecular forces and covalent bonds.