## Q and K

Funmi Baruwa
Posts: 108
Joined: Wed Sep 30, 2020 9:50 pm

### Q and K

Is the only difference between Q and k the fact that Q is measured at any time, and K is only measured when at equilibrium?

Silvi_Lybbert_3A
Posts: 97
Joined: Wed Sep 30, 2020 9:43 pm

### Re: Q and K

Yes Q is the ratio of [P]/[R] when the reaction is not at equilibrium and K is that ratio when the reaction is at equilibrium. They are calculated the same way with the same formula. Side note reminder, when Q<K reaction will proceed to the right (products) and when Q>K reaction will proceed towards left (reactants).

Allan Nguyen 2G
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Joined: Wed Sep 30, 2020 9:49 pm

### Re: Q and K

You can calculate Q to figure out where the reaction will proceed if given the equilibrium constant, K. Similar to what Silvi said, when Q<K the reaction will proceed to the right and vice versa when Q>K the reaction will proceed to the left.

Kelly Yun 2I
Posts: 103
Joined: Wed Sep 30, 2020 10:03 pm

### Re: Q and K

I was confused on this as well, but I try to remember Q as reaction quotient and K as equillibrium constant and that helps me tell the difference!

Will Skinner
Posts: 84
Joined: Wed Sep 30, 2020 9:28 pm

### Re: Q and K

Correct, K is the ratio of products and reactants at equilibrium and Q is the ratio when it is not at the equilibrium. The difference between Q and K tells us which direction the reaction will move.

Shrinidhy Srinivas 3L
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### Re: Q and K

As stated above, Q is the reaction quotient at a given period of time (that is not necessarily equilibrium). K is the reaction proportion at equilibrium specifically. When Q < K, the reaction will shift towards the products. When Q > K, the reaction will shift towards the reactants. When Q = K, the reaction is at equilibrium and it will not shift. Hope this helps!

Devin Patel 2D
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Joined: Tue Nov 17, 2020 12:18 am

### Re: Q and K

Yes, Q is the reaction quotient and is essentially the ratio of products/reactants whenever the reaction is not at equilibrium. K is the ratio when the reaction is at equilibrium. The reaction quotient can help us figure out if the reaction is not at equilibrium and can inform us whether the reaction at that moment will favor the forward or reverse reactions.

Kyle Dizon 3A
Posts: 91
Joined: Mon Oct 05, 2020 12:16 am

### Re: Q and K

Q and K are found using the same concept of Product/Reactants. The main difference between the two is that the reaction quotient (Q) is identified when the reaction is not at equilibrium while K is the actual equilibrium constant. Comparing these two will provide us information if the reactant or product is favored in the reaction.

Matlynn Giles 2E
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### Re: Q and K

The best way I've found to remember this is Q stands for quotient!

reva_bajjuri
Posts: 104
Joined: Fri Oct 02, 2020 12:17 am

### Re: Q and K

Silvi_Lybbert_3A wrote:Yes Q is the ratio of [P]/[R] when the reaction is not at equilibrium and K is that ratio when the reaction is at equilibrium. They are calculated the same way with the same formula. Side note reminder, when Q<K reaction will proceed to the right (products) and when Q>K reaction will proceed towards left (reactants).

I thought q could equal the value of k and that indicates the system is at equilibrium

AJForte-2C
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### Re: Q and K

I understand the relationship between Q and K, but can someone tell me why/when we would want to measure the Q/when it would be important?

Isaias Gomez D3A
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### Re: Q and K

Quotient starts with Q. Thats what Q is, while K is the constant

Hannah Lechtzin 1K
Posts: 89
Joined: Wed Sep 30, 2020 9:31 pm

### Re: Q and K

Yep! Q and K are found exactly the same way, so K is just Q when a reaction is at equilibrium.

Posts: 73
Joined: Wed Sep 30, 2020 9:34 pm

### Re: Q and K

That's correct! Q is the reaction quotient, so it happens anytime, but K is only for when the reaction is at equilibrium. Otherwise, you calculate them the same way.

Aria Movassaghi 1A
Posts: 97
Joined: Wed Sep 30, 2020 9:40 pm

### Re: Q and K

yes, k is measured at equilibrium

Sable Summerfield
Posts: 30
Joined: Tue Nov 17, 2020 12:18 am

### Re: Q and K

Allan Nguyen 2G wrote:You can calculate Q to figure out where the reaction will proceed if given the equilibrium constant, K. Similar to what Silvi said, when Q<K the reaction will proceed to the right and vice versa when Q>K the reaction will proceed to the left.

Could we go more in depth as to WHY when Q<K the reaction will proceed to the right and when Q>K the reaction will proceed to the left? If the Q value is P/R when the reaction is NOT at equilibrium and K is P/R when it is at equilibrium, why does this mean that when Q>K the reaction will shift to the left?

Posts: 87
Joined: Wed Sep 30, 2020 9:40 pm

### Re: Q and K

Yep! It's in the name itself. Q is the reaction quotient and K is the equilibrium constant.

AHUNT_1A
Posts: 110
Joined: Wed Sep 30, 2020 9:41 pm

### Re: Q and K

Using this as a reference

Posts: 84
Joined: Wed Sep 30, 2020 9:49 pm

### Re: Q and K

Yeah Q tells us the ratio of P/R concentrations at any time while K is the P/R concentrations at equilibrium. However, even though they may be calculated the same way knowing Q and K can tell us which direction the reaction tends to.

austin-3b
Posts: 59
Joined: Wed Nov 11, 2020 12:18 am

### Re: Q and K

Yes, Q is any time. You would measure Q at that moment to determine the direction of the reaction.

If Q<K, the reaction is going right; more products are made
If Q>K, the reaction is going left; more reactants are made

Tiao Tan 3C
Posts: 100
Joined: Wed Sep 30, 2020 9:59 pm

### Re: Q and K

Yes you're correct. Q is measured at any instant of the reaction but K is only measured after the reaction reaches equilibrium.

Jaclyn Dang 3B
Posts: 105
Joined: Wed Sep 30, 2020 10:02 pm

### Re: Q and K

Q is at any time and they are calculated the same exact way. You would measure Q at that moment to determine the direction of the reaction.
if Q=K then the reaction is at equilibrium
If Q<K, the reaction is going right and it favors products
If Q>K, the reaction is going left and it favors reactants

Lung Sheng Liang 3J
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Joined: Wed Sep 30, 2020 9:33 pm

### Re: Q and K

Yes, Q is used when the chemical equation is not at equilibrium

Leyla Anwar 3B
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Joined: Wed Sep 30, 2020 10:03 pm

### Re: Q and K

austin-3b wrote:Yes, Q is any time. You would measure Q at that moment to determine the direction of the reaction.

If Q<K, the reaction is going right; more products are made
If Q>K, the reaction is going left; more reactants are made

Does this mean there can be multiple Q values for different times during the reaction?

David Y
Posts: 90
Joined: Wed Sep 30, 2020 9:49 pm

### Re: Q and K

Yes, K is the equilibrium constant because it represents the ratio of products and reactants at equilibrium.

jasmineculilap_3F
Posts: 85
Joined: Wed Sep 30, 2020 9:40 pm

### Re: Q and K

AJForte-2C wrote:I understand the relationship between Q and K, but can someone tell me why/when we would want to measure the Q/when it would be important?

You could measure Q in order to figure out what direction the reaction is going towards. When Q<K, the reaction favors the forward reaction/products and if Q>K, the reaction is favors reactants (reverse reaction).

Daniela Santana 2L
Posts: 86
Joined: Wed Sep 30, 2020 9:59 pm

### Re: Q and K

Hi! Yes you are right about Q and K. Q is the reaction quotient and you can calculate this at any time. K is the equilibrium constant and you can only calculate this at equilibrium.

Gwen Casillan 3E
Posts: 46
Joined: Sat Sep 07, 2019 12:17 am

### Re: Q and K

Yes, Q is the reaction quotient, and K is the equilibrium constant. Q indicates that there is a shift, while K indicates equilibrium. We use Q and compare it to K to see whether the reaction is at equilibrium (Q=K), favors reactants (Q>K), or favors products (Q<K).

SLai_1I
Posts: 93
Joined: Wed Sep 30, 2020 9:52 pm

### Re: Q and K

Yes, K can only be measured when the reactant is at equilibrium. Q, on the other hand, can be measured at any time of the reaction to determine the direction the reaction will continue.

Nick Saeedi 1I
Posts: 102
Joined: Wed Sep 30, 2020 9:39 pm

### Re: Q and K

Yes Q is a constant for the reaction at a time not at equilibrium which is compared to k in order to see which direction the reaction is shifting towards.

Neel Sharma 3F
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### Re: Q and K

Yes. A good way to think of it is that K is simply the name of Q when the system is at equilibrium. Everywhere else it is just the reaction quotient, Q. Hope this helps!

Hannah Lechtzin 1K
Posts: 89
Joined: Wed Sep 30, 2020 9:31 pm

### Re: Q and K

Yep! They are calculated the same way, K just denotes that the reaction is at equilibrium.

305572629
Posts: 86
Joined: Wed Sep 30, 2020 9:41 pm

### Re: Q and K

Q is the reaction quotient and K is the equillibrium constant. If Q>K the reaction will shift left, and if Q<K the reaction will shift right.

DominicMalilay 1F
Posts: 99
Joined: Wed Sep 30, 2020 9:36 pm

### Re: Q and K

Being more general, Q is the more specific term compared to K which specifies a specific instance in the rxn!

joshtully
Posts: 87
Joined: Wed Sep 30, 2020 9:36 pm

### Re: Q and K

K is just Q at equilibrium.

Michael Cardenas 3B
Posts: 48
Joined: Wed Sep 30, 2020 9:34 pm

### Re: Q and K

Yeah K and Q are the same ratio but K is at equilibrium concentrations while Q is at any point of time during the reaction.

Kelly Ha 1K
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### Re: Q and K

Although calculated the same way, Q is the reaction quotient while K is the equilibrium constant. K is basically just Q at a specific point (at equilibrium).

Posts: 88
Joined: Wed Sep 30, 2020 9:38 pm

### Re: Q and K

Q is the reaction quotient, which is essentially the ratio of products to reactants of a reaction that is not at equilibrium. K, on the other hand, is the equilibrium constant, which is the ratio of products to reactants at equilibrium. You can relate Q to K to find out which direction the reaction will begin to favor.

Posts: 87
Joined: Wed Sep 30, 2020 9:40 pm

### Re: Q and K

Yes, that's correct! When Q and K are different, we can tell that the concentrations are not at equilibrium.

Xinying Wang_3C
Posts: 94
Joined: Wed Sep 30, 2020 9:39 pm

### Re: Q and K

Basically yes, Q is the equilibrium for a reaction measured at any time, and k should be a constant number for the same equation conducted under the same temperature.

Laura 3l
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### Re: Q and K

K is calculated when the reaction is at equilibrium at a certain temperature, while Q can be calculated at anytime when the reaction is not at equilibrium at that same temperature . By solving for Q and comparing it to K you can determine which way the reaction needs to shift, if there is more reactants that still need to form product (shift right) or vice versa.

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### Re: Q and K

One way to compare Q and K is that if Q>K then you have more products in the reaction that the amount of products there should be at equilibrium. Therefore, to reach equilibrium, the reaction will shift left. If Q <K then there are more reactants present than the amount of reactants that there should be at equilibrium, so the reaction will shift right to produce more products and balance.

Cecilia Cisneros 1F
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### Re: Q and K

Essentially, yes. Q is measured at any point in the reaction that is not at equilibrium. However, K must be measured only at equilibrium.

John_Tran_3J
Posts: 91
Joined: Wed Sep 30, 2020 9:58 pm

### Re: Q and K

Q, the reaction quotient is the concentration at ANY TIME during the reaction. K is when the equilibrium is set between the products and reactants.

Sejal Parsi 3K
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### Re: Q and K

Yes, Q is the reaction quotient and can be found at any time, but K can only be found at equilibrium.

emwoodc
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Joined: Fri Aug 09, 2019 12:16 am

### Re: Q and K

You are correct! K is found at equilibrium and Q is found at any time of the reaction!

Carly_Lipschitz_3H
Posts: 93
Joined: Wed Sep 30, 2020 9:56 pm

### Re: Q and K

Yes, Q can be measured at any time. K is the equilibrium constant, so it stays constant. Q can be greater than, equal to, or less than K and helps you determine if the forward or reverse reaction is favored.