Polar and non polar

(Polar molecules, Non-polar molecules, etc.)

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Nahelly Alfaro-2C
Posts: 59
Joined: Wed Nov 15, 2017 3:04 am

Polar and non polar

Postby Nahelly Alfaro-2C » Fri Jun 01, 2018 12:03 am

I understand that a polar molecule must have polar bonds with dipoles that do not cancel. I also understand that a nonpolar molecule must have zero an electric dipole moment which is possible if it contains non-polar bonds. My question is how can you identify the difference and determine whether a molecule is polar or not. can an example and explanation be provided as to why it would either be polar or non-polar

Marisol Sanchez - 1E
Posts: 38
Joined: Fri Apr 06, 2018 11:05 am

Re: Polar and non polar

Postby Marisol Sanchez - 1E » Fri Jun 01, 2018 9:05 am

To determine if a molecule is polar or nonpolar it is easiest to start by drawing its dipole moment or shape. This can be done by basically just drawing the Lewis structure first, then add arrows pointing to the more electronegative atom from each individual bond. For example, in CCl4, all the arrows point from the carbon to each individual chlorine atom because chlorine is more electronegative and you can see from this that the dipole moments would cancel out. If they cancel out, it is nonpolar, or if do not cancel out, it is polar. I am not sure how to attach pictures here to be honest, but maybe someone else will be able to show you what it looks like.

Ashley Martinez 1G
Posts: 26
Joined: Fri Apr 06, 2018 11:03 am

Re: Polar and non polar

Postby Ashley Martinez 1G » Sun Jun 03, 2018 10:24 pm

I also had issues visualizing this. To clarify, would the dipoles cancel out if the vectors are going in opposite directions? Thanks!

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Re: Polar and non polar

Postby Chem_Mod » Sun Jun 03, 2018 10:50 pm

Vectors will only cancel out if they are in opposite direction AND of same magnitude.

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