## Q and K [ENDORSED]

Andy_Yousif_1A
Posts: 10
Joined: Wed Sep 21, 2016 2:59 pm

### Q and K

Is there an actual difference in the formulas for Q different from K?

Shirley_Zhang 3O
Posts: 35
Joined: Wed Sep 21, 2016 2:56 pm

### Re: Q and K

There is no difference between the two formula.

Kendall Schemmer 1I
Posts: 20
Joined: Fri Sep 29, 2017 7:03 am

### Re: Q and K

No difference in the formulas, just the fact that K is the constant at chemical equilibrium and Q refers to the initial concentrations of the reactants and products.

Jennie Fox 1D
Posts: 66
Joined: Sat Jul 22, 2017 3:01 am

### Re: Q and K  [ENDORSED]

The two formulas are the same. You compare Q to K in order to determine which way the reaction will shift (sit). If Q<K, it will shift/sit right (toward products), if Q>K, it will shift/sit left (towards reactants).

AtreyiMitra2L
Posts: 169
Joined: Fri Sep 29, 2017 7:03 am
Been upvoted: 1 time

### Re: Q and K

There is no difference between the two formulas. The molar concentrations, however, in k should be the ones at equilibrium. At Q, the molar concentrations can be at any point.

Kyung_Jin_Kim_1H
Posts: 53
Joined: Thu Jul 27, 2017 3:00 am

### Re: Q and K

As the others have mentioned, there is no difference in the formula, but it's important to use the right numbers. Use the concentrations/pressures provided when the system isn't at equilibrium to calculate Q.

Michael Lee 2I
Posts: 51
Joined: Fri Sep 29, 2017 7:05 am

### Re: Q and K

There are no difference between the formuals. However, Q refers to the reactants and products whereas K refers to the chemical equilibrium.

Yizhou Liu 3L
Posts: 19
Joined: Fri Sep 29, 2017 7:07 am

### Re: Q and K

The formula of Q and K are the same, but they have different meanings.

204918982
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

### Re: Q and K

There is no difference between the formulas, but they calculate different things. K is calculated by using the equilibrium concentrations and Q is calculated by using the concentrations at a different time during the reaction.

Yeyang Zu 2J
Posts: 58
Joined: Fri Sep 29, 2017 7:06 am

### Re: Q and K

K is the equilibrium constants of the reaction, which is only changed with the temperature. However, Q is the reaction rate at any time of the reaction, which will be changed with add/remove of the substance,volume,and concentrations. In the other words, we say Q includes K; K is one value of Q in the spacial condition.

Justin Lai 1C
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

### Re: Q and K

Q is the formula for concentration of products/reactants at any time. K is the ratio of products to reactants at equilibrium and they use the same formulas

AtreyiMitra2L
Posts: 169
Joined: Fri Sep 29, 2017 7:03 am
Been upvoted: 1 time

### Re: Q and K

The formulas are the exact same.

Nathan Tu 2C
Posts: 46
Joined: Fri Sep 29, 2017 7:07 am

### Re: Q and K

There is no difference in the formulas themselves. It is just that K specifically refers to when the reaction is at equilibrium and Q refers to any moment of time aside from that.

105085381
Posts: 44
Joined: Fri Sep 28, 2018 12:15 am

### Re: Q and K

K is found using concentrations at equilibrium, BUT to calculate Q do we just use the initial concentrations or concentrations at any given time?

ran2000
Posts: 66
Joined: Fri Sep 28, 2018 12:15 am

### Re: Q and K

No difference. It's the same but K is when equilibrium is achieved. Q is at any point of the reaction.

shaunajava2e
Posts: 66
Joined: Fri Sep 28, 2018 12:26 am

### Re: Q and K

the formulas are the same, K is at equillibrium

Tony Chung 2I
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

### Re: Q and K

both of the formulas for Q and K are the same!

805087225
Posts: 30
Joined: Thu Jun 07, 2018 3:00 am

### Re: Q and K

Virtually no difference between how we calculate Q and K, but they just tell us different things ( which - either reactant or product is in excess and which side the equilibrium sits)

mbaker4E
Posts: 69
Joined: Fri Sep 28, 2018 12:26 am

### Re: Q and K

There is no difference in the way we calculate Q and K, the difference is that Q is associated with initial values and K is associated with equilibrium values.

juleschang16
Posts: 55
Joined: Fri Sep 28, 2018 12:19 am

### Re: Q and K

You can calculate Q and K the same way by following the formula [products]/[reactants] . The only difference is that the reaction quotient, Q is for ANY TIME during the reaction while the values for K are always the concentrations at equilibrium.

Hannah Yates 1K
Posts: 59
Joined: Fri Sep 28, 2018 12:27 am

### Re: Q and K

No difference in the way you calculate Q and K, but there is a major difference in what they mean. Q means the ratio of Products and reactants at any given point of the reaction, but K is the ratio of Products and Reactants at equalibrium. When comparing Q and K, it can tell us which reaction rate is higher.

KHuang1L
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

### Re: Q and K

Same formulas but they calculate for different things

deniise_garciia
Posts: 30
Joined: Wed Nov 16, 2016 3:04 am

### Re: Q and K

How do you know when to use Q or K, is there a certain calculation? Or would the question specify so?

Zubair Ahmed 1L
Posts: 81
Joined: Fri Sep 28, 2018 12:16 am

### Re: Q and K

Both have the same formula, but they calculate different things.

Deepika Pugalenthi 1A
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

### Re: Q and K

There is no difference in the formulas for Q and K. The main difference lies in what Q and K are calculated for. K is the equilibrium constant, therefore it can only be applied to identify when the reaction is at equilibrium. Q, on the other hand, is the reaction quotient and can be calculated at any time during the reaction. The main purpose of Q is to compare it to K and identify which direction the reaction should be proceeding in order to attain equilibrium. When Q is equal to K, then the reaction is at equilibrium.

Dayna Pham 1I
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Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 3 times

### Re: Q and K

105085381 wrote:K is found using concentrations at equilibrium, BUT to calculate Q do we just use the initial concentrations or concentrations at any given time?

Yes. Q can be calculated at any time in the reaction, and then you would compare it to the given equilibrium constant, K, to determine if the reaction is at equilibrium, and if not, then which directional reaction is favored. Hope this helps!

Danny Zhang 4L
Posts: 62
Joined: Fri Sep 28, 2018 12:26 am

### Re: Q and K

The formulas for both Q and K are the same. K specifically tells us when the reaction is at equilibrium. Q can be be found during any instance of the reaction in order to determine which direction the reaction is going when it is compared to K.

Anmol_cheema_2F
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: Q and K

Both Q and K use the same formula.

riddhiduggal
Posts: 30
Joined: Fri Sep 28, 2018 12:21 am

### Re: Q and K

K and Q are calculated in the same way.

Erin Kim 2G
Posts: 75
Joined: Fri Sep 28, 2018 12:26 am

### Re: Q and K

Q and K have the same formula, they are both the concentration of the products divided by the concentration of reactants.

Jasmine Chow 1F
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Joined: Fri Sep 28, 2018 12:16 am
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### Re: Q and K

There is no difference.

MichelleTran 1I
Posts: 40
Joined: Fri Sep 28, 2018 12:23 am

### Re: Q and K

The formulae themselves have no difference, but K is only used when the chemical reaction is at equilibrium. Using the equation with Q helps you determine whether the reaction goes forward or in reverse to reach equilibrium.

Tony Ong 3K
Posts: 63
Joined: Fri Sep 28, 2018 12:23 am

### Re: Q and K

nope no difference! Hope that helped because I have to sleep now!

Tuong Nguyen 2I
Posts: 71
Joined: Fri Sep 28, 2018 12:26 am
Been upvoted: 1 time

### Re: Q and K

Tony Ong 3K wrote:nope no difference! Hope that helped because I have to sleep now!

Goodnight!

JacobHershenhouse3G
Posts: 32
Joined: Thu Jan 10, 2019 12:17 am

### Re: Q and K

Yes K and Q have the same formula. More importantly, though, they represent different things that, when compared, yield answers to the direction of the reaction at a certain point in time. K=constant (at equilibrium only), Q=constant (at any point in time throughout the reaction). Each specific value for Q and K are found using the same formula using concentration or pressure based on given variables, as you know. So, when Q<K the reaction favors the products (i.e. will produce more of them), when Q>K the reaction favors the reactants (reverse reaction occurs more often), and when Q=K you've reached or returned to equilibrium. Hope this is helpful. :)

Philipp_V_Dis1K
Posts: 32
Joined: Fri Sep 28, 2018 12:20 am

### Re: Q and K

Since they have the same formula, it is just a view of the value of the products and reactants and using this value to see how it applies to the equilibrium constant.