Final answer:
Carbon dioxide (CO₂) has polar covalent bonds but is nonpolar overall due to its linear geometry where dipole moments cancel out. On the contrary, water (H₂O) is a polar molecule because it has a bent structure causing its dipole moments not to cancel.
Step-by-step explanation:
To identify the molecule(s) containing non-polar covalent bonds, we must consider both the electronegativity values of the atoms involved and the molecular geometry. In the case of carbon dioxide (CO₂), we have a linear molecule with oxygen atoms that are more electronegative than the central carbon atom, creating two polar covalent bonds. However, these individual dipoles pointing outward from the central carbon atom to each oxygen atom cancel out because they are of equal strength and are orientated directly opposite each other. Therefore, the overall molecule of CO₂ is nonpolar.
On the other hand, in a water (H₂O) molecule, the structure is bent due to the lone pairs on the oxygen atom, and the bond moments do not cancel out. Although H₂O contains polar covalent bonds due to the difference in electronegativity between hydrogen and oxygen, the geometry of the molecule results in a net dipole moment, making water a polar molecule. Thus, H₂O does not have non-polar bonds.