polar and nonpolar molecules

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

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Emely Reyna 1F
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

polar and nonpolar molecules

Postby Emely Reyna 1F » Sun Jun 03, 2018 8:40 pm

4.25 on the h.w. asks to determine which of the following molecules is polar or non polar.

For example, CH2Cl2

How can I determine this from the structure?

Jose Lupian 1C
Posts: 27
Joined: Fri Apr 06, 2018 11:03 am

Re: polar and nonpolar molecules

Postby Jose Lupian 1C » Sun Jun 03, 2018 9:06 pm

You can determine whether molecules are polar or nonpolar by looking at the dipole moments of bonds. If the direction of the dipole moments cancel out, then the molecule would be nonpolar. On the other hand, if they don't cancel out, then the molecule is polar.

SammiOrsini_1B
Posts: 45
Joined: Fri Apr 06, 2018 11:04 am

Re: polar and nonpolar molecules

Postby SammiOrsini_1B » Sun Jun 03, 2018 9:10 pm

How do we know which dipole moments cancel each other?

jadam_1E
Posts: 30
Joined: Fri Apr 06, 2018 11:01 am

Re: polar and nonpolar molecules

Postby jadam_1E » Sun Jun 03, 2018 9:16 pm

A CH2CL2 molecule is tetrahedral because there are four regions of electron density (VSEPR Model Formula of AX4). The C-H and C-Cl bonds are both polar in nature and looking at a tetrahedral shape, no bonds are opposite eachother and hence no bonds will cancel, causing the molecule to be polar.

Nienjou Claire 1E
Posts: 30
Joined: Fri Apr 06, 2018 11:05 am

Re: polar and nonpolar molecules

Postby Nienjou Claire 1E » Mon Jun 04, 2018 7:11 pm

would you just have to know which bonds/molecules would produce a charge or is there a way to tell by looking at the structure?

kellyz_1C
Posts: 33
Joined: Fri Apr 06, 2018 11:05 am

Re: polar and nonpolar molecules

Postby kellyz_1C » Tue Jun 05, 2018 1:51 am

it's helpful to look at the symmetry of a molecule when determining if it's polar or nonpolar. most symmetrical molecules are nonpolar and the opposite is also true. however differing electronegativities can also have an effect on the polarity of a molecule


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