umm can sumone explain le chatelier's principle in simple terms?? (1 Viewer)

[charmed_cuties]

i'm having trouble remembering the whole effects of changing concentration, volume and pressure

 

[t-i-m-m-y]

Originally posted by charmed_cuties
i'm having trouble remembering the whole effects of changing concentration, volume and pressure

basically le chatelier's principle deals with what happens to an equilibrium reaction when the conditions are changed:

any change will affect the equilibrium, such that it counteracts the change - hehe i still remember, tho not the exact words

so for pressure:

say u have an equation as follows:

2A + B <----> 5C

okay where A, B C are ur elements/compounds whatever.. so changing the pressure will either force the equilibrium to the left or the right. lets assume that they are all gasse. so if we increase the pressure, the equilibrium wants to make itself smaller- lol not quite the way to say it but it moves to the side with less moles in our case, the one on the left with A and B.. cuz less moles= less volume.. which is what a higher pressure will bring about

mm my ramblings long enough.. hehe that deals with pressure; u'll learn this again in chem monitoring and management

but basically to master le chateliers principle, u need to be able to fully understand what his principle is really all about. from there, u can apply it to any reaction and u just have to logically work it out

another quick example; change of temp

say our reaction was exothermic if it goes towards the C side (right); that means it gives out heat... so if we up the temperature in our reaction vessel, or whevere the reaction takes place, it means that there is more heat. so the reaction shifts backwards to the left, to counteract the extra heat, as it does not want to make "even more" heat

but yeah u have to work it out each time

hope that helps

wheres abdoo- he'll give u a full blown phd thesis on this

 

[charmed_cuties]

okies thanx for the help!!! so star wat subjects do u do??

 

[t-i-m-m-y]

hehe okay

star- so well put

 

[charmed_cuties]

oi timmy did u get a good mark for ur chemistry hsc exams??

 

[mitochondria]

not necessary left or right because that depends on the equation which you have. It's better to use example so here's one:

CO2 + H2O ----> H2CO3

Carbon Dioxide + Water ----> Carbonic Acid


Clearly, the pressure of CO2 is higher on the right hand side. So if you ADD CO2 to this system, the system will try to maintain the equilibrium by adjusting the equilibrium, thus, the equilibrium shifts to the right because the pressure is LOWER on that side.

if the equation was written backwards then you should say the equilibrium shifts to the left hand side.

So basically, the side which counteract the change is the side which the reaction will shift to.



As for your question about pressure and mole, you are right there because the same moles of different gaseous substances theortically occupy the same amount of space. Imagine the chamical A and chemical B are gases which will form compound AB upon reaction. You place them in a box that has a fixed size, if such reaction does not proceed to completion:

A + B <-----> AB

when you increase substance A by injecting more into the box, clearly more AB will form to DECREASE the box otherwise the box will explode.

Note: If you continue to inject chemical A in the box, chemical B will eventually "run out" because more compound AB are form. In that case, the if the box would not explode, you the equilibrium will stop shifting, that means, in real life situations, the concentraion of chemical A will increase because the equilibrium has stopped



Hope that helps

 

[t-i-m-m-y]

So basically, the side which counteract the change is the side which the reaction will shift to.

yep thats right; i found it easier to find a method to work out which side it shifts to; as they could write it backwards

Originally posted by charmed_cuties
oi timmy did u get a good mark for ur chemistry hsc exams??

dunno, is 94 considered good? lol i've applied to be a tutor

 

[t-i-m-m-y]

and as u can see... if i were to tutor

i wouldn't just give the straight answer; as i learnt from my bio teacher; who was mad the best way to teach is to get them to think it thru

yes, so u can see where my first post is comin' from

 

[charmed_cuties]

omg i am so intimidated by that mark!!! shit i'm no where near ur standard, i think i need to study harder. 94 for chemistry is excellent i bet ya wen i do the hsc my mark is gonna be so crap compared to ur mark

 

[t-i-m-m-y]

Originally posted by charmed_cuties
omg i am so intimidated by that mark!!! shit i'm no where near ur standard, i think i need to study harder. 94 for chemistry is excellent i bet ya wen i do the hsc my mark is gonna be so crap compared to ur mark

lol want tutoring? hehe

don't worry, and don't make comparisons i guess it kinda makes u feel stupid etc. just do ur best -good luck!

 

[charmed_cuties]

yeah i wish i had tutoring but hey lets jsut say i'm not that well off and yeah sorta outta cash for the week

 

[t-i-m-m-y]

Originally posted by charmed_cuties
yeah i wish i had tutoring but hey lets jsut say i'm not that well off and yeah sorta outta cash for the week

lol okies. i wasn't serious anyways

i didn't have tutoring for chem tho, as long as u study hard

read my "guide" in my sig; maybe peek at my notes i've put up

 

[mitochondria]

Originally posted by t-i-m-m-y
don't worry, and don't make comparisons i guess it kinda makes u feel stupid etc. just do ur best -good luck!

True true, why worry? just give it your best and you will be happy with what you get Besides, as long as you get in the course you want to do in uni (I assume that's what you want to do) then it won't matter how well you did in the HSC (I am not saying this because it got a crabbie chemistry mark which was VERY disappointing) lol.. i literally screwed up 'cause my HSC results turened out to be unexpected hahaa.. but anyways, back to the point, don't make comparisons! That's a big NO NO! You'll be depressed if you do that (maybe I'm taking cuties too seriously here? hehee.. but still) the best way to score a good mark in science subjests is to understand things

 

[mitochondria]

Originally posted by t-i-m-m-y
i didn't have tutoring for chem tho, as long as u study hard

*nod nod* tutoring is... useless I think, UNLESS your teacher is too imcompotent then you should consider to be tutored (or maybe you do insane maths.. a.k.a. 4U/ Extension 2 ---> 'cause you'll never get enough time to understand everything and go in the exam confidently [with the exception of super genius] *sigh* meee probably was too dumb to do it lol) don't need a tutor *nod nod*


btw timmy.. I'm soooo confused about my enrolment.. I've just recieved an e-mail for transferring my program from Advanced Science to combined Advanced Science and Arts.. but I have no idea whatsoever how to lost blah I don't know what I'm talking about.. the enrolment interface isn't that good i think

 

[hipsta_jess]

umm can sumone explain le chatelier's principle in simple terms??

if you shove something in or take something out or alter the conditions, the equilibrium is going to try and resist the change

 

[charmed_cuties]

umm thanx for the advice about achieving the best in a scienc3e subject! well i reckon tutor does do much each either i just need to study more i guess and ask for help wen i need it

 

[mitochondria]

yuuuuuuuup! just give us a yell when you need help and seriously.. doing good in the HSC just doesn't happen like "okay, I am going to beat the HSC." Also, the reason for saying understand is more important than remembering is because, when you understand things in a HSC science subject, you can derive ideas more complex ideas from simpler ideas and by doing that you make yourself more flexible and adaptable to different sort of questions. Also, a tip which I found helpful is: try connecting everything together. This will maintain a good integrity in your mind and notes and makes your thinking to become more tenacious. Also a good way to get good marks in the HSC (science subjects) because you are required to do so. Good luck!

 

[elizabethy]

i loved this Le Chatelier's principle....but now i don't remmeber it exactly!!

 

[mushroom_head]

doesn't equilibrium just shift to the side with the lower volume?

 

[t-i-m-m-y]

Originally posted by mushroom_head
doesn't equilibrium just shift to the side with the lower volume?

thats misleading. to answer ur question: no

mito- yep the enrolment is complicated; what subjects u doing