Question

Why is CF4 a non polar molecule, even though it contains polar bonds?

Answer 1

This is just because Carbon can have up to 4 bonds. Since it has all the exact same atoms filling those bonds, Fluorine, all around the molecule is the same charge.
Carbon doesn't arrange its bonding partners in a square like the left, instead it arranges them in a 3-dimensional shape similar to a tetrahedron. It's hard to show this shape in 2-dimensions, but that's what I'm trying to depict there. This tetrahedral shape is what spreads out the fluorine atoms the furthest from each other, since they're all the same charge and want to be as far apart as possible.

It's kind of like if you were carbon and wanted to hold two magnets of the same pole next to each other. You can hold onto them, but they repel each other and try to get as far away as possible. But don't confuse this with what's really happening, the fluorine aren't repelling each other due to magnetic forces, but electric forces which are similar.