Explain why water molecules are polar, why ethane, C2H6, molecules are nonpolar, and why carbon dioxide, CO2, molecules are nonpolar.
Excerpt From: Mark Bishop. “Chapter 12 – Liquids: Condensation, Evaporation, and Dynamic Equilibrium – Atoms First.” iBooks.
The correct answer and explanation is:
Explanation of Molecular Polarity
- Water (H₂O) – Polar Molecule
Water is polar because of its bent molecular shape and the difference in electronegativity between hydrogen and oxygen. Oxygen is more electronegative than hydrogen, meaning it pulls the shared electrons closer to itself, creating a partial negative charge (δ⁻) on oxygen and partial positive charges (δ⁺) on hydrogen. The bent shape (due to lone pairs on oxygen) prevents the dipoles from canceling out, resulting in a net dipole moment, making H₂O a polar molecule. - Ethane (C₂H₆) – Nonpolar Molecule
Ethane is nonpolar because it consists of carbon-carbon and carbon-hydrogen bonds, which have very small differences in electronegativity (C ≈ 2.5, H ≈ 2.1). Additionally, ethane has a tetrahedral geometry around each carbon atom, and its molecular symmetry ensures that any slight dipoles cancel out. With no significant separation of charge, C₂H₆ is nonpolar. - Carbon Dioxide (CO₂) – Nonpolar Molecule
Although CO₂ has polar bonds (due to the electronegativity difference between carbon and oxygen), the molecule is linear (O=C=O). The dipole moments of the two polar bonds cancel each other out because they are equal in magnitude but opposite in direction. This results in no net dipole moment, making CO₂ a nonpolar molecule.
Thus, water is polar due to its bent shape and dipole moment, while ethane and carbon dioxide are nonpolar due to their molecular symmetry canceling out any dipole moments.
Now, I’ll generate an image to visually illustrate these molecular structures and their polarity.
Here is a scientific diagram illustrating the polarity of Water (H₂O), Ethane (C₂H₆), and Carbon Dioxide (CO₂). It visually represents their molecular structures, dipole moments, and polarity characteristics. Let me know if you need any modifications!
