CHEMISTRY - dipole moments?

The presence of a dipole moment in a molecule tend to increase the strength of intermolecular interactions (attractions).

In the presence of dipole moments, the molecules are held together by attractions between dipoles, such that the electrostatic forces between the positive ends and the negative ends of neighboring molecules. In the absence of dipole moments, the molecules are held together by attractions instantaneous dipoles and induced dipoles, which is weaker than the former.

"Intermolecular interactions" means the interactions between molecules. They are independent of bond strengths within the individual molecules. Bond strengths are said to be intramolecular (i.e. within the molecules), but not intermolecular (i.e. between the molecules).

Increases it. The molecules need a reason to attract each other. If they are non polar, then fluctuation in electron clouds cause temporary poles and thus weak attraction. When there are diffreneces inthe atoms electro-negativity (attraction of electrons), a permanent dipole is formed and interactions increase.