Q and K

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Funmi Baruwa
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Q and K

Postby Funmi Baruwa » Fri Jan 08, 2021 6:53 pm

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
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Re: Q and K

Postby Silvi_Lybbert_3A » Fri Jan 08, 2021 6:56 pm

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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Re: Q and K

Postby Allan Nguyen 2G » Fri Jan 08, 2021 7:28 pm

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
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Re: Q and K

Postby Kelly Yun 2I » Sat Jan 09, 2021 2:31 am

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
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Re: Q and K

Postby Will Skinner » Sat Jan 09, 2021 9:03 am

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

Postby Shrinidhy Srinivas 3L » Sat Jan 09, 2021 11:25 am

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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Re: Q and K

Postby Devin Patel 2D » Sat Jan 09, 2021 11:28 am

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
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Re: Q and K

Postby Kyle Dizon 3A » Sun Jan 10, 2021 9:39 am

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

Postby Matlynn Giles 2E » Sun Jan 10, 2021 6:58 pm

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

reva_bajjuri
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Re: Q and K

Postby reva_bajjuri » Sun Jan 10, 2021 7:40 pm

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

Postby AJForte-2C » Sun Jan 10, 2021 9:01 pm

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

Postby Isaias Gomez D3A » Sun Jan 10, 2021 9:05 pm

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

Hannah Lechtzin 1K
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Re: Q and K

Postby Hannah Lechtzin 1K » Sun Jan 10, 2021 9:07 pm

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

LarisaAssadourian2K
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Re: Q and K

Postby LarisaAssadourian2K » Sun Jan 10, 2021 9:09 pm

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
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Re: Q and K

Postby Aria Movassaghi 1A » Sun Jan 10, 2021 9:48 pm

yes, k is measured at equilibrium

Sable Summerfield
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Re: Q and K

Postby Sable Summerfield » Sun Jan 10, 2021 10:09 pm

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?

Adrienne Chan 1G
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Re: Q and K

Postby Adrienne Chan 1G » Sun Jan 10, 2021 10:14 pm

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

AHUNT_1A
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Re: Q and K

Postby AHUNT_1A » Sun Jan 10, 2021 10:19 pm

Using this as a reference

Jaden Kwon 3C
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Re: Q and K

Postby Jaden Kwon 3C » Sun Jan 10, 2021 10:29 pm

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
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Re: Q and K

Postby austin-3b » Tue Jan 12, 2021 12:05 am

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
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Re: Q and K

Postby Tiao Tan 3C » Thu Jan 14, 2021 1:41 am

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
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Re: Q and K

Postby Jaclyn Dang 3B » Thu Jan 14, 2021 10:03 am

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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Re: Q and K

Postby Lung Sheng Liang 3J » Sat Jan 16, 2021 3:18 pm

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

Leyla Anwar 3B
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Re: Q and K

Postby Leyla Anwar 3B » Sun Jan 17, 2021 2:50 pm

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
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Re: Q and K

Postby David Y » Sun Jan 17, 2021 5:08 pm

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

jasmineculilap_3F
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Re: Q and K

Postby jasmineculilap_3F » Sun Jan 17, 2021 5:24 pm

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
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Re: Q and K

Postby Daniela Santana 2L » Sun Jan 17, 2021 7:51 pm

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
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Re: Q and K

Postby Gwen Casillan 3E » Sun Jan 17, 2021 7:55 pm

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
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Re: Q and K

Postby SLai_1I » Sun Jan 17, 2021 7:57 pm

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
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Re: Q and K

Postby Nick Saeedi 1I » Sun Jan 17, 2021 8:05 pm

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

Postby Neel Sharma 3F » Sun Jan 17, 2021 8:23 pm

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
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Re: Q and K

Postby Hannah Lechtzin 1K » Sun Jan 17, 2021 8:24 pm

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

305572629
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Re: Q and K

Postby 305572629 » Sun Jan 17, 2021 9:18 pm

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
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Re: Q and K

Postby DominicMalilay 1F » Sun Jan 17, 2021 9:39 pm

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

joshtully
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Re: Q and K

Postby joshtully » Sun Jan 17, 2021 10:48 pm

K is just Q at equilibrium.

Michael Cardenas 3B
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Re: Q and K

Postby Michael Cardenas 3B » Sun Jan 17, 2021 11:05 pm

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

Postby Kelly Ha 1K » Sun Jan 17, 2021 11:06 pm

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).

Mina Tadros 3L
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Re: Q and K

Postby Mina Tadros 3L » Sun Jan 17, 2021 11:09 pm

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.

Adrienne Chan 1G
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Re: Q and K

Postby Adrienne Chan 1G » Sun Jan 17, 2021 11:19 pm

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

Xinying Wang_3C
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Re: Q and K

Postby Xinying Wang_3C » Mon Jan 18, 2021 3:59 pm

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

Postby Laura 3l » Mon Jan 18, 2021 4:20 pm

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.

Faaizah Arshad 1H
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Re: Q and K

Postby Faaizah Arshad 1H » Mon Jan 18, 2021 7:38 pm

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

Postby Cecilia Cisneros 1F » Mon Jan 18, 2021 7:41 pm

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
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Re: Q and K

Postby John_Tran_3J » Mon Jan 18, 2021 7:49 pm

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

Postby Sejal Parsi 3K » Tue Jan 19, 2021 1:34 am

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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Re: Q and K

Postby emwoodc » Wed Jan 20, 2021 7:58 pm

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

Carly_Lipschitz_3H
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Re: Q and K

Postby Carly_Lipschitz_3H » Thu Jan 21, 2021 5:06 pm

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.


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