KC vs KP [ENDORSED]

[Eden Breslauer-Friedman 2A]

If we are given a chemical reaction that has gases involved, do we automatically assume we are calculating KP, or does it depend if we are given values in molar concentrations, or atmospheres/bars?

Thanks!

[Andrew Wang 1C]

It would depend if we are given the values of reactants/products in concentration or bars. I remember some problems in the Audio-Visual modules had us calculate Kc when there were only gases in the reaction.

[SahajDole_1C]

Usually the question should mention what to find but it would depend on the values given.

[Jonathan Batac - 2D]

I would always check what units are given. As you stated, if given concentration (Molarity) usually you would be calculating for Kc, and if given atm/bars usually you would be calculating for Kp.

[Gabriel Nitro 1E]

Hi,

It entirely depends on the context on what you are given. If you are given any information which may lead you to find concentrations (), use . If you are given any information which may lead you to find partial pressures (), then use .

Hope this helps! :)

[Kareena Patel 1G]

If the equation only involves gases, I think it is safe to assume that you should use Kp for the problem.

[Kelly Tran 1J]

The units will tell you whether you are calculating for Kc or Kp. If the molar concentration is given, you are calculating for Kc. If the units of atm/bar is given, you are calculating for Kp.