Different types of K

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Chloe Alviz 1E
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Joined: Sat Aug 17, 2019 12:17 am

Different types of K

Postby Chloe Alviz 1E » Sun Jan 12, 2020 4:44 pm

What's the difference between K and Kc?

Jessica Katzman 4F
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Joined: Mon Jun 17, 2019 7:24 am

Re: Different types of K

Postby Jessica Katzman 4F » Sun Jan 12, 2020 4:45 pm

K is the general notation for the equilibrium constant. Kc is used when we are specifically defining the ratio of the molar concentrations of products and reactants.

Hussain Chharawalla 1G
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Joined: Sat Jul 20, 2019 12:15 am

Re: Different types of K

Postby Hussain Chharawalla 1G » Sun Jan 12, 2020 4:47 pm

K is the equilibrium constant. It gives you the ratio between products and reactants. It can represent Kc or Kp

Kc is the equilibrium constant written in terms of concentration. So it is concentration of products over reactants.

Kp is the equilibrium constant in terms of partial pressure.

Emil Velasco 1H
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Joined: Wed Nov 21, 2018 12:19 am

Re: Different types of K

Postby Emil Velasco 1H » Sun Jan 12, 2020 4:49 pm

K = Kc = Kp

They are just different notations for whatever phase your equation is dealing with (e.g. gas w/ pressure)

Similarly, K = Q = Qc = Qp

Anna Chen 1K
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Joined: Thu Jul 25, 2019 12:18 am

Re: Different types of K

Postby Anna Chen 1K » Sun Jan 12, 2020 5:21 pm

K is the equilibrium constant.
Kc is defined by molar concentrations while Kp is defined by the partial pressures of the gasses.

chari_maya 3B
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Joined: Sat Sep 07, 2019 12:18 am

Re: Different types of K

Postby chari_maya 3B » Sun Jan 12, 2020 5:34 pm

How do you convert from Kc to Kp?

Sydney Pell 2E
Posts: 100
Joined: Wed Sep 11, 2019 12:17 am

Re: Different types of K

Postby Sydney Pell 2E » Sun Jan 12, 2020 5:37 pm

The notation of K depends on what information they give you in the equation and what phase it occurs in. If the problem gives you the partial pressures of the gases in the reaction, you would be using Kp. If the molar concentrations are given, then Kc. Either way, K always stands for the equilibrium constant.

Vuong_2F
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Joined: Sat Sep 14, 2019 12:17 am

Re: Different types of K

Postby Vuong_2F » Sun Jan 12, 2020 5:47 pm

chari_maya 3B wrote:How do you convert from Kc to Kp?


Lavelle hasn't mentioned anything about this in lecture so I'm not sure if this is necessary information, but the relationship between the two is Kp=Kc(RT)^Δn

AGaeta_2C
Posts: 112
Joined: Wed Sep 18, 2019 12:21 am

Re: Different types of K

Postby AGaeta_2C » Sun Jan 12, 2020 8:07 pm

chari_maya 3B wrote:How do you convert from Kc to Kp?


I believe this was briefly discussed in the second lecture. To convert between partial pressure and concentration for a gas, you use the Ideal Gas Equation, PV=nRT.
Where, P= pressure, V= volume, n= number of moles, and (RT) are constants.
To calculate pressure of a gas when you know its concentration, rearrange the equation:

P = (n/V)(RT)
P = (conc)(RT)

To calculate concentration of a gas when you are given its pressure, rearrange the equation:

(n/V) = (P/(RT))
(conc) = (P/(RT))

Jack Riley 4f
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Joined: Sat Aug 24, 2019 12:17 am

Re: Different types of K

Postby Jack Riley 4f » Sun Jan 12, 2020 8:08 pm

K is the general equilibrium constant while Kc specifically refers to the equilibrium constant of molar concentrations


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