Calculating K

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Eileen Si 1G
Posts: 120
Joined: Fri Aug 30, 2019 12:17 am

Calculating K

Postby Eileen Si 1G » Wed Jan 22, 2020 12:19 am

Is it possible to calculate K for an unbalanced equation? Or can you only calculate Q?

Hope Hyland 2D
Posts: 50
Joined: Wed Feb 20, 2019 12:16 am

Re: Calculating K

Postby Hope Hyland 2D » Wed Jan 22, 2020 12:26 am

You can only calculate K for equations that are at equilibrium, which is usually indicated in the problem. If the equation is not balanced, then balance it and then find K (assuming the reaction is at equilibrium). Conversely, Q is calculated when the reaction is NOT at equilibrium, and is simply the ratio of products to reactants. You should also balance the equation before calculating Q.

kim 2I
Posts: 105
Joined: Thu Jul 25, 2019 12:17 am

Re: Calculating K

Postby kim 2I » Wed Jan 22, 2020 12:56 am

You should always balance your chemical reactions before doing any sort of calculations so that the molar ratios are accurate. If by unbalanced you're referring to the fact that the reaction hasn't reached equilibrium yet, then the K cannot be calculated since K represents the EQUILIBRIUM constant. Only the reaction quotient can be calculated.

Joanne Lee 1J
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Joined: Thu Jul 25, 2019 12:15 am

Re: Calculating K

Postby Joanne Lee 1J » Wed Jan 22, 2020 11:23 pm

K can only be used when you know that the reaction is at equilibrium. Therefore, if the unbalanced equation is at equilibrium, simply balance the equation and then you can find K.

Jasmine Fendi 1D
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Joined: Sat Aug 24, 2019 12:15 am

Re: Calculating K

Postby Jasmine Fendi 1D » Wed Jan 22, 2020 11:26 pm

Always balance the equation! When calculating K, the incorrect coefficients will change the exponents in the equation and you would not calculate the correct equilibrium constant

MTanikella_1K
Posts: 110
Joined: Sat Jul 20, 2019 12:16 am

Re: Calculating K

Postby MTanikella_1K » Thu Jan 23, 2020 12:33 pm

To calculate Q and K, your equation should be balanced.

Gurmukhi Bevli 4G
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Joined: Wed Nov 14, 2018 12:20 am

Re: Calculating K

Postby Gurmukhi Bevli 4G » Thu Jan 23, 2020 8:02 pm

You cannot calculate K for an unbalanced equation, but unless you know the reaction is at equilibrium, you would be calculating Q for a balanced reaction as well. For both the Q and K cases, your reaction still needs to be balanced.

CameronDis2K
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Joined: Wed Feb 20, 2019 12:18 am

Re: Calculating K

Postby CameronDis2K » Fri Jan 24, 2020 2:17 pm

The idea of balancing a reaction is not associated with K; regardless, in order to solve a chemistry problem, the reaction should be balanced (with coefficients). When it is balanced, depending if the information is given for either pressure or concentration of the reactants AND products @ equilibrium, Kc or Kp can be calculated. And the coefficients in the balanced equation is translated to powers: ex. 2NO --> [NO]^2.

Leyna Dang 2H
Posts: 104
Joined: Thu Jul 25, 2019 12:17 am

Re: Calculating K

Postby Leyna Dang 2H » Fri Jan 24, 2020 4:21 pm

Make sure you balance all of your equations. Not doing so could cause you to end up with the wrong K value since your coefficients might be wrong.

Mariah
Posts: 104
Joined: Fri Aug 02, 2019 12:16 am

Re: Calculating K

Postby Mariah » Fri Jan 24, 2020 8:10 pm

Eileen Si 1G wrote:Is it possible to calculate K for an unbalanced equation? Or can you only calculate Q?


An equation must be balanced and at equilibrium to determine K. You must balance the equation before determining either K or Q.

Gabriel Ordonez 2K
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Joined: Sat Jul 20, 2019 12:15 am

Re: Calculating K

Postby Gabriel Ordonez 2K » Sun Jan 26, 2020 11:34 pm

You need to balance the equation because the coefficients will be your concentration exponents in the equilibrium constant. Without the balanced equation, your constant is wrong. Also, without balancing the chemical equation, you are breaking the laws of conservation highlighted in chem 14a.

Gabriel Ordonez 2K
Posts: 113
Joined: Sat Jul 20, 2019 12:15 am

Re: Calculating K

Postby Gabriel Ordonez 2K » Sun Jan 26, 2020 11:34 pm

You need to balance the equation because the coefficients will be your concentration exponents in the equilibrium constant. Without the balanced equation, your constant is wrong. Also, without balancing the chemical equation, you are breaking the laws of conservation highlighted in chem 14a.

sarahartzell1A
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Joined: Fri Sep 28, 2018 12:17 am

Re: Calculating K

Postby sarahartzell1A » Sun Jan 26, 2020 11:48 pm

The equation should be balanced.

Jacob Motawakel
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Re: Calculating K

Postby Jacob Motawakel » Mon Jan 27, 2020 12:01 am

You need balanced equations so you can have the correct coefficients when calculating k. When calculating k the coefficients of the balanced equation become the exponents of the k equation.

005162902
Posts: 102
Joined: Wed Sep 18, 2019 12:15 am

Re: Calculating K

Postby 005162902 » Mon Feb 03, 2020 5:49 pm

You should always make sure a chemical reaction is balanced before proceeding to make any calculations. Always.

HuyHa_2H
Posts: 100
Joined: Wed Sep 11, 2019 12:15 am

Re: Calculating K

Postby HuyHa_2H » Sun Feb 09, 2020 5:37 pm

The equation has to always be balanced to find both K and Q. The only difference is that K is for when it's at equilibrium whereas Q is not.


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