Kc vs Kp

[EthanPham_1G]

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]

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]

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]

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

[Rosa Munoz 2E]

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

[Vinita Saxena 2I]

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

[Sanjana Borle 2K]

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

[Shivam Rana 1D]

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]

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

[Tanmay Singhal 1H]

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

[Emil Velasco 1H]

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)