Lewis acids and bases

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Lucy Wang 2J
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Lewis acids and bases

Postby Lucy Wang 2J » Sun Nov 08, 2020 9:39 pm

how can we tell the difference between a molecule that is an acid or a base? do they react differently in chemical reactions?

Sara_Lim_2C
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Re: Lewis acids and bases

Postby Sara_Lim_2C » Sun Nov 08, 2020 9:41 pm

The acid is the molecule that accepts an electron pair, and the base is the molecule that donates an electron pair. Hope that helps a lil!

Logan Wiedemann 3J
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Re: Lewis acids and bases

Postby Logan Wiedemann 3J » Sun Nov 08, 2020 9:41 pm

HI!
I have written in my notes from the last lecture that a species that donates an electron pair is a Lewis base, and a species that accepts an electron pair is a Lewis acid. Hopes this helps you a bit!!!

Dylan_Nguyen_2C
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Re: Lewis acids and bases

Postby Dylan_Nguyen_2C » Sun Nov 08, 2020 9:50 pm

To tell if a compound is a Lewis acid or Lewis base, we need to determine if it is likely to donate or receive a pair of electrons. If the compounds donates a pair, then it would be considered a Lewis base, while if it receives a pair of electrons it would be a Lewis acid.

Simrah_Ahmed1J
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Re: Lewis acids and bases

Postby Simrah_Ahmed1J » Sun Nov 08, 2020 9:53 pm

You need to determine which compound is gaining more electrons than its atoms originally are supposed to have, that one is the lewis acid, the other one by default has less than its atoms originally had and is therefore the lewis base

Savana Maxfield 3F
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Re: Lewis acids and bases

Postby Savana Maxfield 3F » Sun Nov 08, 2020 10:07 pm

Adding onto each response above, the acid donates hydrogen ions, while the base accepts hydrogen ions in the reaction. To determine which substance donates hydrogen ions vs accepts hydrogen ions, count the number of hydrogens in each substance before and after the reaction. Obviously we are not quite to this unit yet, but just in case you were interested! :-)

Ryan Hoang 1D
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Re: Lewis acids and bases

Postby Ryan Hoang 1D » Sun Nov 08, 2020 10:12 pm

Adding on some additional info you don't need to know quite yet...
There are actually different defintions of acids and bases!
There are definitions like Bronsted Lowry definition--> in which an acid is a substance that donates protons(H+), and a base accepts protons (H+).
There is also Arrhenius definition: where in acids: H+ is released in excess in H20, in base: OH- is released.
And lastly, there is the Lewis acid/base definition, in which only electrons are looked at: lewis acids are those that accept electrons, while bases donate electrons.
But you don't need to know the first two until much later!

joshtully
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Re: Lewis acids and bases

Postby joshtully » Sun Nov 08, 2020 11:40 pm

Acids accept electron pairs, while bases donate electron pairs.

Adam_ElSayed_3B
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Re: Lewis acids and bases

Postby Adam_ElSayed_3B » Sun Nov 08, 2020 11:41 pm

You could use pKa, which is a numerical value representing the acidity of a molecule, or just look at the molecule itself to see if it would accept or give electrons.

IreneSeo3F
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Re: Lewis acids and bases

Postby IreneSeo3F » Sun Nov 08, 2020 11:47 pm

Lewis acids are electron acceptor and lewis bases are electron donor. When you look at their chemical structure, the acid should be able to accept an electron pair while the base should be able to donate an electron pair.

Alexa Pham 1D
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Re: Lewis acids and bases

Postby Alexa Pham 1D » Mon Nov 09, 2020 9:07 am

Lewis acids accept electrons and Lewis bases donate electrons. A way that I try to remember it is that Lewis Acids Accept electrons. And then I just remember that the other one donates.


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