K and Q

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Jessica Lutz 2E
Posts: 56
Joined: Fri Sep 29, 2017 7:04 am

K and Q

Postby Jessica Lutz 2E » Tue Nov 21, 2017 6:49 pm

What is the difference between K and Q conceptually and in how you calculate them?

Morgan Baxter 1E
Posts: 50
Joined: Thu Jul 27, 2017 3:00 am

Re: K and Q

Postby Morgan Baxter 1E » Tue Nov 21, 2017 7:07 pm

K and Q are calculated the same way. If the reaction is aA + bB --> cC + dD, then K= [C]^c x [D}^d / [A]^a x [B]^b . K is when the equation is at equilibrium, Q is when the reaction is not at equilibrium. Based upon the values of K and Q, you can determine if a reaction is at equilibrium or how the reaction will proceed in order to reach equilibrium.

Posts: 52
Joined: Sat Jul 22, 2017 3:01 am

Re: K and Q

Postby skalvakota2H » Tue Nov 21, 2017 9:32 pm

Think of K as the equilibrium constant, and equilibrium is the final stage of the reaction. Thus, K describes the final concentrations of products and reactants. On the other hand, Q is simply a reaction quotient, which means the expression is a relative ratio of products and reactants at a given instant.

Mathematically, both are calculated in the same way. Upon calculating the values for K and Q, you must compare the two in order to determine in what way a reaction will progress.

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