Types of Equilibrium Constants

[Gabriel Ordonez 2K]

Are we allowed to interchange the use of Kc and Kp if the question doesn’t specify which type to use?

[Nohemi Garcia 1L]

You can probably figure out which is going to be used if they use the terms "partial pressure" (which means that Kp will be used), or "concentration" (meaning Kc will be used). Kc is also used if the problem says that a certain amount of moles is mixed with a certain amount of solvent in liters.

I wouldn't recommend using them interchangeably, so just use K when in doubt.

[Mulin_Li_2J]

I think if the question does not specify the unit being used, you can freely choose the most logical one: molarity if most of the reactants and products are in aqueous state, or partial pressure (in atms, or in bars, not in other units) if most of the reactants and products are in gaseous state.

[Ariana Iranmahboub1G]

In many questions, they ask whether or not to find Kc or Kp, so that would be a good indication of which one to use. I wouldn't use them interchangeably because if it is a partial pressure, you would want to use parenthesis when finding the equilibrium constant and if it is a concentration, you would want to use brackets when you show your work.

[005384106]

In what instances would the state of a molecule be important? (gaseous, aqueous, solid, or liquid)

[JNie1L]

When working with aqueous solutions use Kc because it is referring to molarity or concentration. When working with gases use Kp because each gas has its own partial pressure.

[Sean Tran 2K]

When there are gases, use Kp to show partial pressure, and when there are aqueous solutions, use Kc to show molarity.

[J Medina 2I]

In what instances would the state of a molecule be important? (gaseous, aqueous, solid, or liquid)

Solids and liquids are excluded from calculating K. But, a gaseous reaction indicated using Kp and an aqueous reaction indicates using Kc.