London Dispersion forces

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Neha Gupta 2A
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London Dispersion forces

Postby Neha Gupta 2A » Sun Nov 15, 2020 1:24 pm

Just to clarify, do all molecules experience London dispersion forces or only some? I thought that they were present in all molecules but in Sapling I had to choose between London dispersion forces and other types of forces so I wasn't sure.

Summer_Corona 3L
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Re: London Dispersion forces

Postby Summer_Corona 3L » Sun Nov 15, 2020 1:33 pm

I remember in lecture that Lavelle said dispersion interactions are always present/occurring because of electron density fluctuating which causes fluctuating induced dipole- induced dipole moments.

Kaitlyn Hernandez 3I
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Re: London Dispersion forces

Postby Kaitlyn Hernandez 3I » Sun Nov 15, 2020 1:34 pm

I believe that all molecules have london dispersion forces. The strength of these forces increase with the number of electrons (larger molecules have stronger forces).

Jaden Haskins 2E
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Re: London Dispersion forces

Postby Jaden Haskins 2E » Sun Nov 15, 2020 1:40 pm

All molecules do exhibit London dispersion forces! They exist between ionic and covalent molecules, in both polar and non polar molecules. For my sapling question at least, it was dispersion and dipole-dipole, but the answer should be one that has both unless the question asked just for the strongest force.

Veeda Khan 2E
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Re: London Dispersion forces

Postby Veeda Khan 2E » Sun Nov 15, 2020 1:44 pm

As everyone else said above, all molecules experience LDF, but it's pretty weak.

Chudi Onyedika 3A
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Re: London Dispersion forces

Postby Chudi Onyedika 3A » Sun Nov 15, 2020 4:09 pm

Yes, because electrons will have uneven distribution that results in a temporary dipole.

Tatyana Bonnet 2H
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Re: London Dispersion forces

Postby Tatyana Bonnet 2H » Sun Nov 15, 2020 4:21 pm

Yes all molecules have London dispersion forces, and it is one of the weakest intermolecular forces. When two molecules come in close proximity they "induce" a partial negative/positive on each other instantaneously making it temporary.

Chris_Butler_1A
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Re: London Dispersion forces

Postby Chris_Butler_1A » Sun Nov 15, 2020 5:38 pm

Tatyana Bonnet 3H wrote:Yes all molecules have London dispersion forces, and it is one of the weakest intermolecular forces. When two molecules come in close proximity they "induce" a partial negative/positive on each other instantaneously making it temporary.

I'm unsure if I am correct on this but I believe it was mentioned that elements further to the lower-right of the periodic table tend to see these kinds of interactions more due to the larger number of electrons present within their shells.

Joanne Yuh 3I
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Re: London Dispersion forces

Postby Joanne Yuh 3I » Sun Nov 15, 2020 5:41 pm

Yes, all molecules have London Dispersion Forces. Professor Lavelle said in his lecture that these forces are "always present and attractive." I think this is because the electron densities are always fluctuating, which cause the dipoles to also fluctuate.

Ayesha Aslam-Mir 3C
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Re: London Dispersion forces

Postby Ayesha Aslam-Mir 3C » Sun Nov 15, 2020 9:20 pm

This might be a silly question but are LDF's, dipole induced dipole, and induced dipole-induced dipole the same? My mind is spinning at hte use of the word dipole over and over ahaha.

joshtully
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Re: London Dispersion forces

Postby joshtully » Sun Nov 15, 2020 9:31 pm

All molecules experience London Dispersion Forces.

Kushaal Madadi 2F
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Re: London Dispersion forces

Postby Kushaal Madadi 2F » Sun Nov 15, 2020 11:16 pm

Would anyone be able to elaborate why the charges are always fluctuating throughout the two molecules so that each atom is delta negative for some time and then delta positive?

LovepreetSran_3H
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Re: London Dispersion forces

Postby LovepreetSran_3H » Sun Nov 15, 2020 11:22 pm

Yes, all molecules do have London dispersion forces.

Hasan Mirza 3F
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Re: London Dispersion forces

Postby Hasan Mirza 3F » Sun Nov 15, 2020 11:26 pm

All molecules experience London Dispersion forces. The sapling problem was probably asking you to choose the most apparent force present.

Geethika Janga 1L
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Re: London Dispersion forces

Postby Geethika Janga 1L » Sun Nov 15, 2020 11:28 pm

All molecules do experience London Dispersion Forces but when it comes to problems like that, I think they want us to focus on the stronger intermolecular forces and if there are other forces present, LDFs will always be the weakest.


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