Final answer:
A compound has a net dipole moment if it contains polar bonds and its molecular geometry does not allow for the dipoles to cancel out. H₂S, SF₄, CH₃Cl, and H₂CO are examples of such compounds with a net dipole moment.
Step-by-step explanation:
To determine whether a compound has a net dipole moment, we need to examine both the polarity of its bonds and its molecular geometry. In general, a molecule has a dipole moment if it contains polar bonds and its shape is such that the bond dipoles do not cancel each other out.
- H₂S: Water's cousin, H₂S, has a bent molecular geometry with polar bonds, leading to a net dipole moment.
- Boron trifluoride (BF₃): Though it has polar bonds, BF₃ is a trigonal planar molecule, and its bond dipoles cancel out, leaving it with no net dipole moment.
- SF₄: Sulfur tetrafluoride has a see-saw shape due to the presence of a lone pair on sulfur, which creates a net dipole moment.
- CF₄: This molecule is tetrahedral and the polarities of the C-F bonds cancel due to symmetry, resulting in no net dipole moment.
- CH₃Cl: This molecule, also known as chloromethane, has a tetrahedral geometry. The difference in electronegativity between C-Cl creates a polar bond, contributing to a net dipole moment.
- H₂CO (formaldehyde): This molecule has a trigonal planar structure with polar C=O bond that results in a net dipole moment.
In summary, a molecule with polar bonds may or may not have a net dipole moment; the key is to consider the overall molecular geometry and how the individual bond dipoles interact.