Post by: kenhung123 on June 19, 2010, 04:27:01 pm
Since reversible reactions can go both ways how do you exactly know which is reactants and products?
Is it just the way the reaction is positioned on the page?
Why is it that an exothermic reaction subjected to higher temperature would shift to the left (form reactants and reduce products)
Post by: fady_22 on June 19, 2010, 06:16:28 pm
An exothermic reaction releases energy in the form of heat (usually), and so an increase in temperature (according to Le Chatelier's Principle) will cause there to be a net backwards reaction (which would require energy, and so is endothermic) to oppose the effect of the increase in temp.
Post by: m@tty on June 19, 2010, 10:23:29 pm
Post by: kenhung123 on June 19, 2010, 11:45:55 pm
Post by: Akirus on June 20, 2010, 02:58:06 am
You study way too much m@tty
Funny hearing that coming from the guy that posts the most questions on this board.
Post by: kenhung123 on June 20, 2010, 11:19:41 am
Post by: m@tty on June 20, 2010, 12:47:48 pm
You study way too much m@tty
Lol, I just skimmed A+ notes two nights ago.. Unit 4 seems sooooo small... =\
Post by: Blakhitman on June 20, 2010, 01:28:04 pm
Post by: kenhung123 on June 20, 2010, 01:46:26 pm
Post by: Blakhitman on June 20, 2010, 03:44:51 pm
Extra notes and books etc.
Post by: naved_s9994 on June 20, 2010, 04:48:29 pm
Yes, its the way that its written, i.e. reactantsproducts.
An exothermic reaction releases energy in the form of heat (usually), and so an increase in temperature (according to Le Chatelier's Principle) will cause there to be a net backwards reaction (which would require energy, and so is endothermic) to oppose the effect of the increase in temp.
I believe for an equilibrium reaction when one side of the equilibrium system is favoured, we use a two single headed arrows with a larger arm - indicating the side that is favoured.
------->
<---
Post by: shinny on June 20, 2010, 05:03:54 pm
Yes, its the way that its written, i.e. reactants
An exothermic reaction releases energy in the form of heat (usually), and so an increase in temperature (according to Le Chatelier's Principle) will cause there to be a net backwards reaction (which would require energy, and so is endothermic) to oppose the effect of the increase in temp.
I believe for an equilibrium reaction when one side of the equilibrium system is favoured, we use a two single headed arrows with a larger arm - indicating the side that is favoured.
------->
<---
That's really just for explanatory purposes. Normally they just stick with the same double arrow, and whichever side is favoured will be indicated in the equilibrium constant (K) which typically always accompanies any equilibrium reaction.
Post by: naved_s9994 on June 20, 2010, 07:40:40 pm
Yes, its the way that its written, i.e. reactants
An exothermic reaction releases energy in the form of heat (usually), and so an increase in temperature (according to Le Chatelier's Principle) will cause there to be a net backwards reaction (which would require energy, and so is endothermic) to oppose the effect of the increase in temp.
I believe for an equilibrium reaction when one side of the equilibrium system is favoured, we use a two single headed arrows with a larger arm - indicating the side that is favoured.
------->
<---
That's really just for explanatory purposes. Normally they just stick with the same double arrow, and whichever side is favoured will be indicated in the equilibrium constant (K) which typically always accompanies any equilibrium reaction.
Okay, thanks for that information :)
Post by: kenhung123 on June 20, 2010, 07:47:51 pm
Post by: m@tty on June 20, 2010, 08:16:26 pm
And I don't really understand your question. What do you mean by "normally"? And "the same" as compared to what?
Post by: shinny on June 20, 2010, 08:18:42 pm
Hmm doesn't really make sense how you can alter the yield without altering the rate of a forward/backward reaction. Like if everything proceeds normally, it would have the same yield?
Basically what m@tty said, but yeh, you don't necessarily have to run faster to run further; you can just take a longer time to get there.
Post by: physics on June 20, 2010, 08:28:06 pm
Post by: kenhung123 on June 20, 2010, 08:54:25 pm
Post by: naved_s9994 on June 20, 2010, 09:47:01 pm
Hence a system will resist any changes made to its eq by opposing the change.
And yes, hence the relative amounts of reactants and products then may be changed.
Post by: fady_22 on June 21, 2010, 06:48:26 pm
Like doesn't Le Chateliers principle describe the establishment of new equilibrium as being one that does not alter the rate of a reaction but the yield of products and reactants? Lets say at equilibrium A+B=>C every second 1 A, B and C is formed. If we don't speed up the formation or A's and B's or C's, then how can we alter the amount of A, B, C. i.e. we are consistent that 1 A, B and C is formed per second.
If you change the conditions, the system is no longer at equilibrium.
Therefore, the rate can change to ADJUST to the change in conditions, until a new equilibrium is established.
Post by: kenhung123 on June 21, 2010, 07:05:00 pm