Changing K

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Melody Haratian 2J
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Changing K

Postby Melody Haratian 2J » Sun Jan 10, 2021 9:53 am

Why doesn’t the value of K change when you change the concentration of the reactants or products?
Why does only temperature change K?

Kyla Roche 2K
Posts: 99
Joined: Wed Sep 30, 2020 9:59 pm

Re: Changing K

Postby Kyla Roche 2K » Sun Jan 10, 2021 10:09 am

When you change the amount of product or reactants, according to Le Chatelier's Principle, the reactions will adjust to minimize the amount of change. Therefore, the excess will be used up whether it is a R to P, or a P to R reaction that is necessary.When the temperature is changed, it changes the K value. For endothermic reactions when you increase the heat it is in favor of the forward reaction thus P is created changing the K value. On the other hand, when you increase heat in an exothermic reaction, the formation of reactant is favored thus changing the K value.

Margia Adriano 2A
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Joined: Wed Sep 30, 2020 10:00 pm

Re: Changing K

Postby Margia Adriano 2A » Sun Jan 10, 2021 10:20 am

Hi! Remember that K is just a ratio of the concentration of products and reactants, so when you increase/decrease the concentrations of either one of them, although the system does have new concentrations now, it will eventually balance itself out to match the original ratio or the K value. For example, if I had a ratio of 1:2, but the concentrations were double so now the ratio is 2:4, in essence it's still the same thing. Hope this helps!

Carolina Gomez 2G
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Joined: Wed Sep 30, 2020 9:32 pm

Re: Changing K

Postby Carolina Gomez 2G » Sun Jan 10, 2021 2:32 pm

K is the equilibrium constant represented by products/ reactants.
When you initially change the concentration of the reactants or products, the reaction will not be in equilibrium. After a while, the reaction will go back to equilibrium by forming more of the reactant or product based on what was changed. For example, if you add more reactant, after a while it will be used to form more products until it is back at equilibrium, meaning it has the same ratio of products/ reactants, which will result in the same value of K. Although the value of K is the same, the concentration of the reactants and products will not be the same as initially.

Temperature changes K because, for example, when you add heat in an endothermic reaction it favors product formation, meaning the concentration of products increases, which would change the ratio of products/ reactants.

Anya Holbrook 1E
Posts: 98
Joined: Wed Sep 30, 2020 9:38 pm

Re: Changing K

Postby Anya Holbrook 1E » Sun Jan 10, 2021 2:51 pm

K is the equilibrium constant for a chemical equation, and if you add more products or more reactants, the reaction will run in either the forward or reverse direction to bring the system back to equilibrium, and given that K is a ratio, its value will not change.

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