Polar vs Nonpolar molecules

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Caitlin_Murphy_3C
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Polar vs Nonpolar molecules

Postby Caitlin_Murphy_3C » Sun Nov 18, 2018 3:07 pm

How can you predict whether a molecule is polar or nonpolar based on its lewis structure?

melodyzaki2E
Posts: 61
Joined: Fri Sep 28, 2018 12:18 am

Re: Polar vs Nonpolar molecules

Postby melodyzaki2E » Sun Nov 18, 2018 3:09 pm

if the molecule is asymmetric, the bond dipole moments won't "cancel out" and the molecule will have a net dipole moment and the molecule is therefore polar, but if the molecule is symmetric, dipole moments will usually cancel out. hope this helps.

Arshiya
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Re: Polar vs Nonpolar molecules

Postby Arshiya » Sun Nov 18, 2018 3:23 pm

Like stated above, you can cancel the net dipole moments in order to determine if a molecule is polar or not. However, I think just basing it off the Lewis Structure might not be the best. For me, I like to know the shape of the molecule so I can visualize how the atoms are rearranged and how the dipoles can cancel out. Just a tip :)

KHuang1L
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

Re: Polar vs Nonpolar molecules

Postby KHuang1L » Mon Nov 19, 2018 10:55 pm

Yes, check the relative electronegativity of each atom, and if the electronegativity of the atoms do not cancel out, then the molecule is polar.

Meigan Wu 2E
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Re: Polar vs Nonpolar molecules

Postby Meigan Wu 2E » Tue Nov 20, 2018 12:12 am

You check for electronegativity, dipole moments, and then molecular shape to determine is a molecule is polar or nonpolar.

Stevin1H
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Re: Polar vs Nonpolar molecules

Postby Stevin1H » Thu Nov 22, 2018 12:59 pm

In order to predict whether a molecule is polar or non polar, we would need to draw the best 3D structure of the molecule to determine the dipole moment. When we draw the best 3D structure, we would also need to know the electronegativity of each atom to draw the bond dipoles. If the bond dipoles do not cancel, then the molecule is polar. If the bond cancels all cancel, the molecule is non polar because there is no overall dipole moment. Remember, a non polar molecule can have polar bonds but still be non polar if there is no dipole moment.

Karla_Ocampo 4E
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Re: Polar vs Nonpolar molecules

Postby Karla_Ocampo 4E » Sun Nov 25, 2018 10:14 am

First step in determining if something is polar or nonpolar is drawing the lewis structure. Then you check for electronegativity , as stated below, if it doesn't cancel out then it is polar. It would help to also draw the 3D model to get a more closer look.

KarlaArevalo2F
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Re: Polar vs Nonpolar molecules

Postby KarlaArevalo2F » Sun Nov 25, 2018 7:35 pm

using the 3D model its checking for symmetry and not all polar bonds have nonpolar molecules


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