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Dipole-Dipole Forces

Posted: Wed Nov 13, 2019 12:57 pm
by Tyler Angtuaco 1G
When polar molecules are separated, how do their opposite partial charges on each molecule "merge and cancel" as stated in the textbook?

Re: Dipole-Dipole Forces

Posted: Wed Nov 13, 2019 4:17 pm
by 205296774
The separation of the partial charges creates a dipole where one pole is partially negative and the other is partially positive. I think you are either referring to the overall charge being zero as the two opposite partial charges cancel, or most likely, when two polar molecules (which therefore each have two regions of partial negative charge and partial positive charge) bond: a partial positive of one molecule bonds with the partial negative of the other molecule, cancelling each other out.

Hope this helps!

Re: Dipole-Dipole Forces

Posted: Thu Nov 14, 2019 9:14 am
by Brianna Becerra 1B
An example of this can be seen with BeCl2. When drawing the structure, there are negative dipole charges on boh pf the Cl molecules. Because of this, the charges go away from each other and cancel out so the molecule is now nonpolar. This should not be confused with a molecule such as H20. In this Lewis structure, though the negative dipole is in the center and the arrows seem to cross out, they don't due the bent shape of H2O caused by the Lone pairs on the 0xygen. This molecule is then still polar.
Lewis structure for BeCl2:
http://img1.wikia.nocookie.net/__cb2013 ... /Becl2.png
Lewis Structure for H20:
http://opentextbc.ca/introductorychemis ... ucture.png

Re: Dipole-Dipole Forces

Posted: Thu Nov 14, 2019 7:02 pm
by Victor James 4I
would these molecules that have canceled charges still have dipole-dipole interactions?