Kp vs Kc

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Kp vs Kc

Postby haileyramsey-1c » Tue Jan 14, 2020 10:16 pm

I was wondering what situations you would use Kc vs Kp in and why some reactions with all gases use Kc not Kp?

Harry Zhang 1B
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Re: Kp vs Kc

Postby Harry Zhang 1B » Tue Jan 14, 2020 10:24 pm

If you are given enough information to calculate the molar concentration of all of the species in the reaction, you can use Kc even if the species are all in gaseous state. Sometimes the question only gives partial pressures, which means you can only use Kp in that case.

Daniel Toscano 1L
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Re: Kp vs Kc

Postby Daniel Toscano 1L » Tue Jan 14, 2020 10:49 pm

I think it depends on what is given.

andrewcj 2C
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Re: Kp vs Kc

Postby andrewcj 2C » Tue Jan 14, 2020 11:00 pm

It is important to remember that because of the Ideal Gas Law, gases in equilibrium have concentrations proportional to their partial pressures. This is why both may be used in equilibrium constant calculations, although not with each other.

Caitlyn Tran 2E
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Re: Kp vs Kc

Postby Caitlyn Tran 2E » Tue Jan 14, 2020 11:25 pm

Like other people said, it depends on what is given in the problem. If they prefer a specific form, it will probably be specified or you will be given either concentrations or partial pressures. However, in Lyndon's workshop, he said that concentration is more commonly used, so you can probably assume the problem uses concentrations unless otherwise stated. Hope this helps!

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