Is water a carbon molecule?
No, water is not a carbon molecule. Water's formula is h2o or hydrogen 2oxygen. There is no carbon in water therefore it is not a carbon molecule.
Both carbon dioxide molecules and water molecules have polar bonds, Why then is carbon dioxide a non polar molecule while water is a polar molecule, it depends upon structure of both the molecules, carbon dioxide is a linear molecule so its Dipole moment is zero while water molecule has a net Dipole moment.