What makes a molecule polar, is it simply because of the difference of electro negativities between the atoms or is there more to it?

Question

aaronq · Answer

A molecule is polar when an electric dipole moment is present, this means a separation of charge - which could be partial charges, like in water, or "full" charges like in an ionic bond.

dessyj1 · Answer

How small does the separation of charge have to be in order to classify the molecule as non-polar?

aaronq · Answer

In terms of electronegativities between atoms, 0.4.

dessyj1 · Answer

Alright. What if I had something like this |dw:1442183618149:dw| I think this is a alcohol that that is polar. Did I express the partial charges correctly?