The relationship between Kc and K

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Felicia1E
Posts: 31
Joined: Fri Sep 28, 2018 12:22 am

The relationship between Kc and K

Postby Felicia1E » Wed Jan 09, 2019 10:44 pm

Can somebody explain conceptually why when Kc is greater than K the gaseous mols of reactants are greater than the mols of products and the reaction proceeds forward?

Gillian Murphy 2C
Posts: 30
Joined: Fri Sep 28, 2018 12:22 am

Re: The relationship between Kc and K

Postby Gillian Murphy 2C » Thu Jan 10, 2019 1:14 pm

Kc is used to calculate the equilibrium constant using the concentration of the products and reactants at equilibrium. Kc is essentially a more specific way of saying K, because it specifies that you are calculating it using concentration, whereas Kp is calculated using partial pressure. Q, the reaction quotient, is what you want to find when determining which way a reaction will proceed. It is found the same way that K is, except that it can be calculated at any point during the reaction, not just at equilibrium like when finding K. When Q is less than K, it means that there are more reactants (denominator) than products (numerator). In order to reach equilibrium, Q will have to get larger, so the amount of product will have to increase (larger numerator = larger answer) so that the overall calculation of Q will increase. To get more product, the forward reaction would be favored.

Katelyn Phan 2A
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

Re: The relationship between Kc and K

Postby Katelyn Phan 2A » Thu Jan 10, 2019 1:50 pm

Its not that Kc is greater or less than K, but it is greater or less than Q. K is used in terms of equilibrium. On the other hand Q is used at any time during the reaction. When the mols of reactants are greater than those of products, the reaction proceed forward in order to create more products for the reaction to reach equilibrium.


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