Qc vs. Kc Formula

[Michael Crannell 1H]

Do Qc and Kc have the same formula? If so, what is it and does it involve temperature?

[Simone Byun 1F]

Yes, both Qc and Kc have the same formula. If considering the reaction aA + bB -> cC + dD, then the formula would be Qc/Kc = ([A]^a*[B]^b)/([C]^c*[D]^d). However, Kc is used at equilibrium, and Qc is used to observe the concentrations of reactants and products in comparison to equilibrium. In these instances, the temperature should be constant throughout.

[Clarence Clavite 2K]

You find Qc and Kc using the same equation. The difference is that Qc is used on the concentrations at the current moment in time. Qc is then compared to Kc to figure out the direction of the reaction.