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Problem 3F.5

Posted: Wed Nov 13, 2019 7:35 pm
by Brittney Hun 2C
I know the boiling point is higher for CHI3 than it is for CHF3 because CHI3 is the larger molecule so the dispersion forces are stronger and greater. But since Fluorine is more electronegative does that play any role in the strength of the forces, since it attracts the CH to it?

Re: Problem 3F.5

Posted: Wed Nov 13, 2019 9:09 pm
by 005391550
well i think for intermolecular forces we look at size because the larger atom means a bigger electron density which results in an easily distortable electron cloud. This leads to stronger dipole moments and stronger intermolecular forces. But for electronegativity, i think it plays more of a role in bonds between atoms

Re: Problem 3F.5

Posted: Wed Nov 13, 2019 9:30 pm
by Mashkinadze_1D
This question was asked to Doctor Lavelle today during office hours. He stated that because the difference in size and therefore electron cloud between fluorine and iodine is so large, that it over-arches the difference in electromagnetically. This is a good example of just how strong induced-dipole-induced-dipole forces can really get when the molecules are large in size and have a lot of electrons to be distorted.

Re: Problem 3F.5

Posted: Thu Nov 14, 2019 1:36 am
by Jialun Chen 4F
The dominant force to be considered in 3F 5(c) is the dipole-dipole force, which depends on the size of the molecule; since Iodine is larger than Fluorine, Iodine experience higher diploe moment, which results in a stronger dipole-dipole force.