Q and K

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Bianca Barcelo 4I
Posts: 74
Joined: Fri Sep 28, 2018 12:17 am
Been upvoted: 1 time

Q and K

Postby Bianca Barcelo 4I » Sun Jan 20, 2019 7:13 pm

When comparing Q and K, what does that exactly tell us?

Diviya Khullar 1G
Posts: 59
Joined: Fri Sep 28, 2018 12:19 am

Re: Q and K

Postby Diviya Khullar 1G » Sun Jan 20, 2019 7:21 pm

Q is the reaction quotient and K is the equilibrium. Q basically tells us the ratio of the concentration or partial pressure of the products to that of the reactants when the reaction is not at equilibrium, while K tells the same thing when the reaction is at equilibrium. Comparing the two not only tells us whether or not the reaction is at equilibrium but can also tell us what direction the reaction will proceed in to reach equilibrium if it is not already at equilibrium. If QK then the reverse reaction will be favored. If QK then the forward reaction will be favored.

Celeste 1I
Posts: 44
Joined: Fri Sep 28, 2018 12:18 am

Re: Q and K

Postby Celeste 1I » Sun Jan 20, 2019 8:20 pm

K tells us the equilibrium constant and Q is the ratio of the concentration of products and reactants at any given time. You can use K to find whether a reaction is in equilibrium and which side it it more likely to favor. If Q is less than K then the reaction will shift right and if Q is greater then K it will shift to the right.

Jonathan Pai 2I
Posts: 121
Joined: Fri Sep 28, 2018 12:27 am

Re: Q and K

Postby Jonathan Pai 2I » Sun Jan 20, 2019 8:32 pm

K uses only equilibrium concentrations. Q can use any concentration at any time, which tells us where the reaction will go.

Mercan Bayazit 4E
Posts: 18
Joined: Fri Sep 28, 2018 12:20 am

Re: Q and K

Postby Mercan Bayazit 4E » Sun Jan 20, 2019 9:26 pm

K is the equilibrium constant so the reaction needs to be at equilibrium in order for us to calculate K. Q, on the other hand, can be calculated at any time during the reaction and there does not need to be an equilibrium.

Carine Tamamian 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

Re: Q and K

Postby Carine Tamamian 2B » Sun Jan 20, 2019 9:37 pm

If Q < K, then [R] > [P] and forward reaction is favored
If Q > K, then [R] < [P] and reverse reaction is favored
Q=K then reaction is at equilibrium

Carlos De La Torre 2L
Posts: 60
Joined: Tue Oct 09, 2018 12:16 am

Re: Q and K

Postby Carlos De La Torre 2L » Mon Jan 21, 2019 3:21 pm

Q and K are very similar, at equilibrium Q = K but any other time than that Q won't equal K but it will tell us which side will be favored in order to get to K.

Jason Ye 2I
Posts: 33
Joined: Fri Sep 28, 2018 12:22 am

Re: Q and K

Postby Jason Ye 2I » Mon Jan 21, 2019 4:29 pm

Q is like a hypothetical reaction and K is an established equilibrium constant

Rehan Chinoy 1K
Posts: 67
Joined: Fri Sep 28, 2018 12:25 am

Re: Q and K

Postby Rehan Chinoy 1K » Mon Jan 21, 2019 4:51 pm

The value Q is useful because in comparison to a K value for a reaction it tells us whether products or reactants are favored (which direction the reaction will go towards)

Ricardo Martin 1J
Posts: 63
Joined: Fri Sep 28, 2018 12:15 am

Re: Q and K

Postby Ricardo Martin 1J » Wed Jan 23, 2019 10:04 am

If Q > K then a reverse reaction is favored.
If Q < K then a forward reaction is favored.

Brian Chang 2H
Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

Re: Q and K

Postby Brian Chang 2H » Wed Jan 23, 2019 11:22 am

Q is the reaction quotient which can be at any time.
K is the equilibrium constant (only at equilibrium, duh.)
If Q > K then the reverse reaction is favoured.
If Q < K then the forward reaction is favoured.

Basically, it tells us which direction the reaction sits.


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