finding K Value

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katherinemurk 2B
Posts: 68
Joined: Wed Nov 15, 2017 3:02 am

finding K Value

Postby katherinemurk 2B » Wed Jan 09, 2019 4:23 pm

In some questions they ask to find the K value from reactions where the coefficients were either divided or multiplied by a certain number, such a 2. How come when you multiply by 2, you have to square the given K value, and when you divide by 2, you square root the given K value?

Charles Hood Disc 1C
Posts: 39
Joined: Fri Sep 28, 2018 12:19 am

Re: finding K Value

Postby Charles Hood Disc 1C » Wed Jan 09, 2019 4:34 pm

This is because you raise the concentration or partial pressure to the power of its respective coefficient in the equation. When you divide an exponent by 2 it is the same thing as square rooting. Or when you multiply it by 2 it is the same as squaring it.

As an example:
2(3/2) = sqrt(23)
22^2 = 2(2*2)= 24

Lia Inadomi 1I
Posts: 62
Joined: Fri Sep 28, 2018 12:15 am

Re: finding K Value

Postby Lia Inadomi 1I » Wed Jan 09, 2019 5:04 pm

Stoichiometric coefficients are used as the exponent when calculating the equilibrium constant. So if it was 2CO2 then it will be [CO2]^2 in when finding K.

Sophie Roberts 1E
Posts: 61
Joined: Fri Sep 28, 2018 12:17 am

Re: finding K Value

Postby Sophie Roberts 1E » Wed Jan 09, 2019 8:57 pm

In the expression, you must put the concentrations of the reactants and products to the power of their stoichiometric coefficients!

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