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Topic: Adding Heat to Exothermic Reaction  (Read 17771 times)

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Offline momento

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Adding Heat to Exothermic Reaction
« on: October 05, 2009, 01:59:52 AM »
Hi all!!

If you add heat to an exothermic reaction, considering Le Chatelier's principles, should the forward reaction rate increase of decrease?

Intuitively, I would assume that adding heat to any reaction (generally speaking) should increase forward reaction. (More collisions, ie. more product).  However, if in an exothermic reaction heat can be considered a "product", shouldn't the reaction be pushed to the left, thereby decreasing the forward reaction rate?

I'm terribly confused! Help please! :)

Offline Borek

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Re: Adding Heat to Exothermic Reaction
« Reply #1 on: October 05, 2009, 02:59:04 AM »
To some extent this is a trick question. Have you ever heard about reaction rate decreasing in higher temperature?
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Offline Beatle

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Re: Adding Heat to Exothermic Reaction
« Reply #2 on: December 12, 2009, 12:45:05 AM »
No, but if the rate increases, hence adding heat to an exothermic reaction pushes the formation of product, which is responded to with la Chetuer's principal of compensating that shift by pushing the reaction to the left, hence removing the extra products formed due to the increase in temp. thats how i understood it, so the rate of reaction will increase, but the overal product would be the reactants, or more of them.

Offline savy2020

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Re: Adding Heat to Exothermic Reaction
« Reply #3 on: December 12, 2009, 01:11:41 AM »
If you add heat to an exothermic reaction, considering Le Chatelier's principles, should the forward reaction rate increase of decrease?
Intuitively, I would assume that adding heat to any reaction (generally speaking) should increase forward reaction. (More collisions, ie. more product). 
Hi
For ANY reaction as temperature increases rate increases according to Arrhenius equation.
Also Le Chatelier principle has nothing to do with this.

However, if in an exothermic reaction heat can be considered a "product", shouldn't the reaction be pushed to the left, thereby decreasing the forward reaction rate?
Even in an equillibrium condition, increasing temperature increases the rate of forward reaction. But at the same time it also increases the rate of backward reaction. If the forward reaction is exothermic, the increase in the rate of backward reaction is more than that of the forward reaction thereby shifting the equilibrium to the left as predicted by le chatelier's principle.

P.S. Think about why increase in rate of Backward reaction is more than that of forward reaction.
:-) SKS

Offline Beatle

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Re: Adding Heat to Exothermic Reaction
« Reply #4 on: December 17, 2009, 09:29:42 AM »
If the forward reaction is exothermic, the increase in the rate of backward reaction is more than that of the forward reaction thereby shifting the equilibrium to the left as predicted by le chatelier's principle.


thats what I said,(in different words) and if Le Le Chatelier principle has no place or factor in this , why are you referring to it? Id imagine, you did, like I, because with such conditions, the extra heat may create more product, which is responded too in an analogous manner, such is the case with THE PRINCIPAL YOU ARE STATING PLAYS NO PART.

tHE SYSTEM WANTS TOO MAINTAIN EQUILIBRIUM, SO THE BACKWARD REACTION JUMPS A NOTCH, CALL IT WHAT YOU LIKE.

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