Q vs K [ENDORSED]

[hannahdaijo_4H]

What exactly is the difference between the reaction quotient and the equilibrium constant?

[Grace Kim 1J]

K is the constant of a certain reaction when it is in equilibrium, while Q is the quotient of activities of products and reactants at any stage of a reaction. The direction of a reaction can be determined by comparing Q and K.

The difference is that equilibrium constant (K) is the ratio between the concentrations of products and the concentrations of reactants at equilibrium.

[Courtney Quan 1C]

As mentioned above, K as the equilibrium constant is calculated when the reaction is in equilibrium. Q, the reaction quotient, is found when the reaction is at any point other than equilibrium- in other words, when the reaction is not at equilibrium. While K and Q are calculated the same way ([P]/[R]), comparing the two values is helpful in indicating which direction a reaction will proceed. For instance, when Q > K, more products/insufficient reactants are present at that instance than during equilibrium, so the reaction will proceed towards the left to make more reactants.

[yuetao4k]

Q can be calculated at any given point of the reaction. K is calculated when the system is in equilibrium.

[Jasmine Chow 1F]

The Q is the same thing as the K value however it is the constant when the reaction is not in equilibrium. So you often compare K and Q to see which side of the reaction is favored when it is not in equilibrium.