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# Quick equilibria question watch

1. If you increase the heat, then the position of equilibrium moves to remove that heat by doing more of the endothermic reaction.

My question is, wouldnt that cause the concentration to change, which would mean the position of equilibrium moves to repel that change too, causing an increase in temperature?

I am basing this question on this webpage:
http://www.chemguide.co.uk/physical/...ier.html#using

Thanks
2. (Original post by lefneosan)
If you increase the heat, then the position of equilibrium moves to remove that heat by doing more of the endothermic reaction.

My question is, wouldnt that cause the concentration to change, which would mean the position of equilibrium moves to repel that change too, causing an increase in temperature?

I am basing this question on this webpage:
http://www.chemguide.co.uk/physical/...ier.html#using

Thanks
Your first statement is corrent, the endothermic reaction would be favoured.

Your question: yes, the concentrations would change, but that is because of the temperature change. The equilibrium wouldn't shift again to counteract the concentration change.

(Original post by http://www.chemguide.co.uk/physical/equilibria/lechatelier.html)
According to Le Chatelier, the position of equilibrium will move in such a way as to counteract the change.
The change that has happened is the increase in temperature. This causes the position of equilibrium to shift to favour the endothermic reaction.

This doesn't cause it to shift again.
3. (Original post by starofale)
Your first statement is corrent, the endothermic reaction would be favoured.

Your question: yes, the concentrations would change, but that is because of the temperature change. The equilibrium wouldn't shift again to counteract the concentration change.

The change that has happened is the increase in temperature. This causes the position of equilibrium to shift to favour the endothermic reaction.

This doesn't cause it to shift again.
Should I just take it for granted that it wont shift again to compensate for the change in concentrations? I dont undersand why it wouldnt...
4. (Original post by lefneosan)
Should I just take it for granted that it wont shift again to compensate for the change in concentrations? I dont undersand why it wouldnt...
I guess you haven't learnt about the equilibrium constant yet. It actually explains why these changes happen - unlike Le Chatelier's principle, which just says what will happen.
5. (Original post by starofale)
I guess you haven't learnt about the equilibrium constant yet. It actually explains why these changes happen - unlike Le Chatelier's principle, which just says what will happen.
I presume lefneosan is taking unit 2 tommorrow and equilibria constants are in unit 4 (in edexcel anyway).
6. Right you are JTeighty. But can anyone answer my question within the confines of edexcel AS?
7. (Original post by lefneosan)
Should I just take it for granted that it wont shift again to compensate for the change in concentrations? I dont undersand why it wouldnt...
Not sure if this counts as AS chemistry...

The ratio of concentrations of reactantsroducts must stay constant in equilibrium. (so if more reactants are added, the equilibrium shifts to the right to turn more reactants into products and keep the ratio constant - Le Chatelier's principle describes this)

Changes in temperature change the ratio of reactantsroducts needed for equilibrium, so the concentrations change to the new equilibrium values.
8. Thank you starofale, that is a good answer. Thanks

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