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Polar and non-polar molecules

Posted: Wed Nov 15, 2017 7:50 pm
by Yuting Zhu 3D
Could someone please help me with how to determine whether a molecule is polar or not? Is there an easy way to do it?

Re: Polar and non-polar molecules

Posted: Wed Nov 15, 2017 7:58 pm
by Gianna Apoderado 1B
For me, how I identify polar vs nonpolar molecules is by looking at the lewis structures of the molecules, and determining whether on not the shape allows for dipoles (if there are any) to cancel. Take two common examples: CO2 and H20. When you draw the lewis structure for H20, you'll see that the shape is bent, or nonlinear. This means that the dipole moments (with the two oxygens being slightly negative) do not cancel each other out. On the other hand, CO2 is linear, which means that the dipole moments (again with the "arrows" pointing towards the two oxygens), do cancel out because they are pointing in opposite directions on the same plane.

Re: Polar and non-polar molecules

Posted: Wed Nov 15, 2017 11:28 pm
by Catherine Yang 3G
A quick way for me to determine whether a molecule is polar or not is to see whether it is symmetrical. Polar molecules are typically non-symmetrical, meaning that the electrons will be unbalanced and a dipole will form.