Carbon dioxide CO2 is a linear molecule with a carbon atom in the center and two oxygen atoms on either side. The carbon-oxygen bonds are polar due to the difference in electronegativity between carbon and oxygen. However, since the molecule is linear and the two polar bonds are equal in magnitude and opposite in direction, their dipole moments cancel each other out. As a result, the net dipole moment of a carbon dioxide molecule is zero.On the other hand, water H2O is a bent molecule with an oxygen atom in the center and two hydrogen atoms at an angle of approximately 104.5 degrees. The oxygen-hydrogen bonds are also polar due to the difference in electronegativity between oxygen and hydrogen. However, unlike CO2, the molecular geometry of water does not allow for the cancellation of the bond dipoles. The net dipole moment of a water molecule is non-zero and is approximately 1.85 Debye.In summary, the dipole moment of a carbon dioxide molecule is zero due to its linear geometry and the cancellation of bond dipoles, while the dipole moment of a water molecule is non-zero 1.85 Debye due to its bent geometry and the presence of polar O-H bonds.