Problem 43 - Chemistry: An Atoms-Focused Approach

Question

Can a nonpolar molecule contain polar covalent bonds?

Step-by-Step Solution

Answer

Answer: Yes, a nonpolar molecule can contain polar covalent bonds. The overall nonpolar nature of the molecule is determined by the arrangement of atoms that leads to a balanced distribution of charge, with no separation of positive and negative charges across the molecule. An example is carbon dioxide (CO2), which has polar C-O bonds, but its linear geometry causes the bond dipoles to cancel each other out, making the overall molecule nonpolar.

Step 1: Define Polar covalent bond

A polar covalent bond is a type of chemical bond where electrons are shared unequally between two atoms, leading to a distribution of charge (partial positive and negative charges) across the bond. This occurs when the atoms have different electronegativities, resulting in an unequal sharing of the electron density.

Step 2: Define Nonpolar molecule

A nonpolar molecule is a type of molecule with an overall balanced distribution of charge, with no separation of positive and negative charges across the molecule. This can occur when all constituent atoms have the same or similar electronegativities, or when the molecular geometry cancels out the effects of polar bonds.

Step 3: Determine factors that contribute to molecular polarity

The polarity of a molecule is determined by two factors: the difference in electronegativity between its constituent atoms, and the molecular geometry (shape). If there are polar covalent bonds, but they are arranged in such a way that their individual dipoles cancel out, resulting in an overall nonpolar molecule.

Step 4: Example of a nonpolar molecule containing polar covalent bonds

One example of a nonpolar molecule containing polar covalent bonds is carbon dioxide (CO2). In CO2, carbon (C) is in the center, with an oxygen (O) atom on either side. The C-O bonds are polar due to the difference in electronegativity between carbon and oxygen. However, due to the linear geometry of the molecule, the individual bond dipoles cancel each other out, making the overall CO2 molecule nonpolar.

Step 5: Conclusion

So, yes, a nonpolar molecule can contain polar covalent bonds. The key is that the arrangement of the atoms in the molecule must lead to an overall balanced distribution of charge, with no separation of positive and negative charges across the molecule.