**Just because a bond is polar doesn't mean the molecule will be**

All bonds where the atoms in the bond are not the same will be polar (in the sense that the electrons will be unevenly distributed between the two atoms resulting in a dipole). Some bonds (like C-H bonds won't be *very* polar, but they will have some polarity.

Molecules, though, are not polar just because they contain polar bonds. carbon tetrachloride ($\ce {CCl4}$) is a non-polar molecule that contains 4 polar bonds. But the polar bonds have dipoles that are symmetrically arranged around the carbon as a perfect tetrahedron and those dimples therefore cancel each other out leaving the *molecule* with no net dipole moment. Chloroform ($\ce{CHCl3}$) where one of the chlorines has been replaced by a hydrogen, breaking the symmetry, is a fairly polar molecule. Likewise carbon dioxide is non-polar as the structure is linear and therefore the dipoles in the two polar bonds cancel. Carbon monoxide also has a polar C-O bond but there is no second oxygen to cancel out the dipole so it is polar.

So for molecules to be polar they need to contains bonds that are polar but they *also* need to be asymmetric enough for the bond dipoles not to cancel each other out.