Calculating equilibrium concentrations

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Melody Haratian 2J
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Joined: Wed Sep 30, 2020 9:48 pm
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Calculating equilibrium concentrations

Postby Melody Haratian 2J » Sun Jan 24, 2021 10:13 am

Hi guys! When you’re calculating for equilibrium concentrations using ICE tables, when can you ignore the value of X in the denominator?

Jayasree Peri 2J
Posts: 104
Joined: Wed Sep 30, 2020 10:03 pm

Re: Calculating equilibrium concentrations

Postby Jayasree Peri 2J » Sun Jan 24, 2021 10:22 am

If the K-value is less than 10-4, you can ignore it. I believe Dr. Lavelle also said 10-3 in a lecture, but I think it's safer to use 10-4 because sometimes a K-value with 10-3 might make a difference in the concentrations.

Winzel Payumo 1B
Posts: 90
Joined: Wed Sep 30, 2020 9:55 pm

Re: Calculating equilibrium concentrations

Postby Winzel Payumo 1B » Sun Jan 24, 2021 10:46 am

To add on, you can also check by dividing x by your concentration, and if you obtain an answer that it's less than 5%, then it's safe to say that x is negligible.

David Liu 1E
Posts: 85
Joined: Wed Sep 30, 2020 10:07 pm

Re: Calculating equilibrium concentrations

Postby David Liu 1E » Sun Jan 24, 2021 12:08 pm

he said less than 10^-4 during lecture you can ignore the bottom x, and like the person said above, once you check the ionization/deprotonated species % that also has to be less than 5% once you ignore 10^-4


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