Reaction Quotient Q

[Kennedi2J]

How do we distinguish when to calculate Q instead of K or vice versa?

[sbeall_1C]

Q is calculated when an equation is not at equilibrium, whereas K uses equilibrium values!

[TarynD_1I]

We use the reaction quotient Q when the reaction is not in equilibrium, to figure out which way the reaction shifts. Use K when the reaction is at equilibrium.

[Samuel G Rivera - Discussion 4I]

I believe the question you are working on will usually tell you whether you are finding Q or K. From the problems I've done, you are often given a K value at the beginning and are told to find Q in order to compare it to K.

[AveryAgosto]

You are usually told which variable you are looking for but I believe Q is found when the reaction is not at equilibrium and K is found when the reaction is at equilibrium.

[Sydney Pell 2E]

Both Q and K are calculated the same way. Both are the concentration of the products over the concentration of the reactants. K is that value when the reaction is at equilibrium and Q is that value at any other time.

[Karina Kong 2H]

Q is used when the equation is not at equilibrium. We can use Q to determine whether or not the equation will favor the reactants or products.