Keq vs Kc

Rita Chen 1B
Posts: 112
Joined: Sat Jul 20, 2019 12:15 am

Keq vs Kc

Is Keq the same as Kc?
When do we use which?

Paul Hage 2G
Posts: 105
Joined: Thu Jul 25, 2019 12:17 am

Re: Keq vs Kc

Keq is the generalized equilibrium constant, whereas Kc is the equilibrium constant found using concentration values. You would use Kc when you are specifically calculating the equilibrium constant using the molarity values of each reactant/product.

Wendy 1E
Posts: 111
Joined: Sat Aug 17, 2019 12:17 am
Been upvoted: 2 times

Re: Keq vs Kc

Also relevant to this discussion is how Kc is different than Kp. Kp is the equilibrium constant found using partial pressures. The method of calculating Kp is essentially the same as Kc, except Kp is calculated by the partial pressure of products/the partial pressure of the reactants.

Ipsita Srinivas 1K
Posts: 50
Joined: Mon Jun 17, 2019 7:24 am

Re: Keq vs Kc

Ok, just to clarify, Kc and Kp are just types of Keq, and you label the equilibrium constant depending on whether Keq is calculated using partial pressure or molar conc. ?

Maya Beal Dis 1D
Posts: 100
Joined: Sat Aug 17, 2019 12:16 am
Been upvoted: 2 times

Re: Keq vs Kc

When would we need to specify and use Kc as opposed to just using Keq?

BNgo_2L
Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

Re: Keq vs Kc

Ipsita Srinivas 1K wrote:Ok, just to clarify, Kc and Kp are just types of Keq, and you label the equilibrium constant depending on whether Keq is calculated using partial pressure or molar conc. ?

Yes, Kc and Kp are both types of Keq, and Keq is labelled based on whether you use concentration or partial pressures.

BNgo_2L
Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

Re: Keq vs Kc

Maya Beal Dis 1D wrote:When would we need to specify and use Kc as opposed to just using Keq?

I believe we should use Kc any time we use concentrations to calculated Keq.