Kc vs Kp

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EthanPham_1G
Posts: 104
Joined: Sat Jul 20, 2019 12:17 am

Kc vs Kp

Postby EthanPham_1G » Sun Jan 12, 2020 10:21 am

Kc is the equilibrium constant using concentration and Kp is the equilibrium constant using pressure. If you solved for Kc and Kp for the same reaction would they be the same value?

Sarah Blake-2I
Posts: 153
Joined: Fri Aug 30, 2019 12:16 am

Re: Kc vs Kp

Postby Sarah Blake-2I » Sun Jan 12, 2020 10:33 am

It all just depends on what information is given in the problem. If they give you pressure values then I would assume that the concentration would be a different value than the pressure value thus making Kc and Kp different values.

Sanjana Munagala_1j
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Re: Kc vs Kp

Postby Sanjana Munagala_1j » Sun Jan 12, 2020 10:34 am

No the values would not be the same. If they were the same then this conversion P=n/V has to be true for all the gases which is highly unlikely. Kp and Kc values are different but all Kc values are the same for the same reaction at a certain temperature and the same goes for Kp values.

Hope that helps!

Matt F
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: Kc vs Kp

Postby Matt F » Sun Jan 12, 2020 12:25 pm

^So are they the same in the case of ideal gases then? Or whenever P=n/V is true?

Rosa Munoz 2E
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Joined: Wed Sep 18, 2019 12:21 am

Re: Kc vs Kp

Postby Rosa Munoz 2E » Sun Jan 12, 2020 1:57 pm

Kc uses concentrations. Kp uses partial pressures. The answers will not always be the same.

Vinita Saxena 2I
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Joined: Fri Aug 09, 2019 12:16 am

Re: Kc vs Kp

Postby Vinita Saxena 2I » Sun Jan 12, 2020 2:06 pm

The values will not be the same but they will be equal to the same thing after some converting.

Sanjana Borle 2K
Posts: 111
Joined: Fri Aug 09, 2019 12:15 am

Re: Kc vs Kp

Postby Sanjana Borle 2K » Sun Jan 12, 2020 2:08 pm

Kc and Kp eventually lead to the same conclusion, it's just that Kc uses concentration and Kp uses pressure.

Shivam Rana 1D
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Joined: Fri Aug 09, 2019 12:16 am

Re: Kc vs Kp

Postby Shivam Rana 1D » Sun Jan 12, 2020 2:10 pm

Kc and Kp would not be the same values and i think there is a way to convert between the two for gases.

Betania Hernandez 2E
Posts: 107
Joined: Fri Aug 02, 2019 12:15 am

Re: Kc vs Kp

Postby Betania Hernandez 2E » Sun Jan 12, 2020 2:16 pm

Kc and Kp will be two different values since Kc uses the molar concentration value while Kp is uses partial pressure.

Tanmay Singhal 1H
Posts: 143
Joined: Sat Jul 20, 2019 12:16 am

Re: Kc vs Kp

Postby Tanmay Singhal 1H » Sun Jan 12, 2020 2:57 pm

I'm confused on why water isn't counted in the K/Q equation.

Emil Velasco 1H
Posts: 96
Joined: Wed Nov 21, 2018 12:19 am

Re: Kc vs Kp

Postby Emil Velasco 1H » Sun Jan 12, 2020 4:51 pm

Tanmay Singhal 1H wrote:I'm confused on why water isn't counted in the K/Q equation.


Water is not counted because water is a liquid

Solids and liquids are not included in the equilibrium constant expressions (K=P/R)


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