Sapling Week 8 Polarity

[Brendan Duong 1I]

The explanation for #12 says that the reason the molecule is polar is because "oxygen is significantly more electronegative than both carbon and hydrogen. Consequently, methanol is polar." I thought this only means there are polar bonds within the molecule, not necessarily that the entire molecule is polar? I would've thought the overall shape of the molecule is what makes it polar

[Brandon Pham 1H]

For this question you would have to take into account both the polarity of the bonds and the geometry of the molecule. Think about it this way: if you take away the oxygen, it'd be CH4, but the bonds would still be polar. CH4 is a nonpolar molecule, however, because the directions of the bonds cancel the polarity out. Now, add in oxygen and the increased polarity between oxygen and carbon creates a net dipole moment to the right. Now the bonds don't cancel out, making it a polar molecule with polar bonds.

[Jade_Tai_2L]

I kind of had the same thought, but I suppose having polar bonds is correlated with the overall molecule also being polar? Does this mean molecules with polar bonds will always (or more often) be considered as polar overall?

[Hayden Lee 1C]

Due to the fact that a polar bond exists within the molecule, the molecule is polar. There are no other polar bonds in the molecule that cancel out this bond's polarity, so the molecule as a whole is considered to be polar as well. Electrons will be more attracted to the oxygen atom, causing the molecule to have partially charged regions.

[Truman Chong Dis 3G]

I believe polarity is a result of both the bonds and the shape. Shape determines the orientation and symmetry of the molecule; however, the electronegativity difference in the bonds helps determine the polarity when the outer atoms are different from each other. So depending on how the shape orients the most electronegative atoms around the central atom, the symmetry of polarities can become unbalanced and make the molecule polar.

[Catie Donohue 2K]

I think that the explanation is saying that, since the shape of the molecule does not "cancel out" the polar character of the bonds (since oxygen is only on one side and there are lone pairs with an uneven distribution of hydrogen atoms), the molecule itself is polar. Even if it didn't specify, it's both the shape and the polarity of bonds that determine whether the molecule is polar.