H20 consists of polar molecules. CO2 consist of no polar molecules. How do chemist explain this difference?

Polar molecules are the molecules with net dipole due to presence of partial positive charges and partial negative charges. For example of water molecule.

Water molecule is made up of the one oxygen atom and 2 hydrogen atom. There two lone pairs on the oxygen atom which repel both the (O-H) bond pairs away from them. Also oxygen being electronegative attracts the shared pair of electrons towards itself. Due to this the net dipole generates in a water molecule directing towards the lone pairs of the oxygen atom. Hence this makes the water molecule polar

Non Polar molecules are the molecules in which equal sharing of electrons is present that is no net dipole is present. Atom with equal electronegativites have forms polar molecules

Carbon dioxide molecule is a made up two oxygen atoms and 1 carbon atom. Since, there are two electronegative atoms which will attract electrons bond pairs towards itself equally from the both sides which will cancels out the each other dipole resulting in no net dipole in the molecule which makes it non polar molecule.