Understanding Q

[Cecilia Jardon 1I]

Just to clarify, Q is the same chemical reaction but just in the state where it has not yet reached equilibrium?

[MaanasO 1A]

Hi Cecilia!

So Q and K are calculated in the same way but with different concentrations. Think of K as the Q when the reaction is at equilibrium.

Hope that helps!

[Casandra]

Q alone tells you nothing, but once compared to K, it tells you where the reaction is in terms of reaching the equilibrium concentration.

[Cade Okohira 4K]

You find Q and K in the same way, by dividing the concentrations of the products by the concentrations of the reactants. However, K is the equilibrium constant, while Q is the reaction quotient, which is the constant of the equation at any time. Q can then be compared to K to find out whether the equation is shifting to the left or right (or favoring the reactants or products).

[Dayna Pham 1I]

Adding onto what they all said, I’d like to relate this to Le Chatelier’s Principle. When pressure/volume/concentration change, it is Q that changes, not K. However, when temperature changes, then K changes.

[005113695]

Hi!
Q is calculated the same way as K, but instead of being the equilibrium concentration, it can tell you which way the reaction is proceeding.

[MichaelMoreno2G]

Can someone clarify what the significance of Q<K is and vice-versa?

[Karishma_1G]

K>Q and K<Q is significant because it helps us understand whether the reaction has reached equilibrium or not. Since Q (the reaction quotient) is calculated at a specific time during the span of a reaction, by comparing it to K we can see if the reaction has to form more products or reactants to reach equilibrium. If K>Q, the reaction will proceed to the products. If K<Q, the reaction will proceed to the reactants.

[Simmi Diwanji 2B]

The significance of Q<K and vice versa is that it helps determine whether a reaction has reached equilibrium at a certain point in time. If it hasn't reached equilibrium (Q=K), than that means that the reaction will either favor the reactants or products in order to proceed towards equilibrium.

[Sapna Ramappa 1J]

Comparing Q and K allows us to see whether or not the system is at equilibrium. If Q=K, then the system is at equilibrium. Otherwise, we can see if Q>K or if K>Q to determine whether the reaction favors the reactants or the products.