Clarification on Q<K and R&P concentrations

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Sebastian Lee 1L
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Clarification on Q<K and R&P concentrations

Postby Sebastian Lee 1L » Wed Jan 08, 2020 2:47 pm

In lecture, Dr. Lavelle had on the slides that if Q<K, then [R]>[P] and the forward reaction is favored. I understand that when Q is less than K that means the ratio of products over reactants is less, signifying that there are more reactants (and less products) at that time than there would be at equilibrium. Thus, the reaction will form more product. However, even if Q<K, I'm not sure if that always means that [R]>[P], right? For example, you could have a Q greater than 1 which means that there are more products than reactant. However, if K is greater than that Q, it will still favor the forward reaction. Even though there are already more products than reactants, there needs to be even more product to reach equilibrium.

Brian_Ho_2B
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Re: Clarification on Q<K and R&P concentrations

Postby Brian_Ho_2B » Wed Jan 08, 2020 2:57 pm

Yes, just because Q<K doesn't necessarily mean that [R]>[P]. It just means that more product is favored. For instance, Q can be 10^2 and K can be 10^5. There's a lot more product than reactant, but the K requires even more product.

Aman Sankineni 2L
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Joined: Fri Aug 30, 2019 12:17 am

Re: Clarification on Q<K and R&P concentrations

Postby Aman Sankineni 2L » Wed Jan 08, 2020 5:21 pm

Q is mainly used to determine the favored reaction direction. It doesn't necessarily signify that the reactants or products have a higher or less concentration than one another.


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