Could anyone help a GCSE Chemistry Student?

[Guest GCSE dude]

Hi, I'm a GCSE student about to sit my GCSE exams, but there's one thing really thats really bugging me about chemistry. Equilibriums. I don't understand the whole concept of it and the way you can change things to affect the point of equilibrium. My Chemistry Teacher says the Haber Process will definitely come up in the exam, and you need to understand equilibriums to understand the Haber Process. Could anyone please explain equilibriums to me without using advanced Scientific jargon? I'd be really grateful if you could.

[Dak]

pk. heres one which is based on peoples desire to not be too cramped.

 

immajine two rooms which are next to each other, and there are a few doors leading from one to another.

 

all these doors start off locked and closed, and the room on the left starts off jam packed full of people, whereas the room on the right is empty.

 

now, the doors are unlocked and opened.

 

the two rooms will now not be in equilibrium. this is due to the fact that the people in the left room are squished up and desire more personal space, and so there is a reason for them to travel to the room on the right.

 

now imajine it a few minuites later: some people have gone into the spaciouse room on the right, but there are still more people in the room on the left. the people in the room on the right are happy (cos theyve got lots of elbo room) but the people in the room on the left are not happy (cos theyre still a bit cramped). the two rooms are still not in equilibrium. this is due to the fact that there is still a tendancy for people to go from the left room to the right room, whereas nobody in the room on the right wants to go to the left.

 

now immajine the room in another few minutes time. the room on the right now has almost as many people as the room on the left. so now, the people in the room on the right are beginning to get cramped. now, there are people in the left room who are cramped and so will go to the right room to see if its more spatiouse, and also people in the right room who are cramped and so will go to the left room to see if its more spatiouse. the two rooms are still not in equilibrium. basically, as there are still more people in the room on the left (ie, the room on the left is more crowded), there will be more people travelling from the left room to the right room than there are people travelling from the right room to the left room. because the amount of people travelling in one direction does not balance out the amount travelling in the other, the room in still in a state of disequilibria (ie not having attained equilibrium).

 

youll notice that all the while that these two rooms have been out of equilibrium, we have observed a change in the proportion of people in each room -- ie, a couple of minutes after observing the room in disequilibrium, it has changed.

 

a few minutes later, enough people have travelled from the room on the left into the room on the right that there are as many people in the room on the right as there are on the left. some people are still too cramped, but because there are as many people on either side, there will be as many people going from the left room to the right in search of space as there will be people going from right to left. now the room is in equilibrium, as the number of people going left-->right balances the amount of people going right-->left. so, when we look at the room a few minutes later...

 

there are still as many people in the left hand room as there are in the right hand room. a few of the people will have swapped places, but the overall number of people in each room is the same. this is called a dynamic equilibrium because although there are people travelling from room to room (dynamic) the amount of people in either room stays the same (equilibrium).

 

which isnt to say that the amount of people need to be the same in each room to reach equilibrium: its the cessation of overall change which makes the system equilibriated. so, for example, if you immajine cranking up the heat in the left room uncomfortably high, then many people would go to the room on the right to escape it. this would cause the room on the right to become more crowded, and so the more people joined the room on the right, the less space people would have and the more people would decide that it was too crowded and would go check out the room on the right.

 

eventually, after much faffing about, you would reach a point where either:

 

the amount of people going to check out the less-crowded hot room was the same as the amount of people going to check out the cooler but less spaciouse room, so there would be no overall change in the number of people in either room (although there would be more people in the cooler room) -- this would be another dynamic equilibrium

 

OR

 

all the people who could tolerate the heat were in the hot room, everyone who really couldnt tolerate the heat was in the cold room, and everyone who wasnt fond of the heat but could tolerate it had descided on wether they prefered the hot room or the crowded room and gone to the room of their preference (obviousely, they may change their mind: someone who was in the cool room might have gone to the hot room after the cool room became too crowded as more people joined, but over time less people will change rooms and so the level of crowding will remain constant, and so no-one have reason to change there mind anymore).

 

so, noone is changeing rooms and so (obviously) the number in each room will remain the same. this is called a, umm, undynamic equilibrium (possibly)

 

hope that helps.

[Mendelejev]

Woow, great explanation !!! Very nice ! I'll try to remember it for later, when I've became chemistry prof

[Guest GCSE dude]

I *kind of* get it, but its still confusing, can anyone explain it differently?

[Ophiolite]

I was going to use a variant of Dak's explanation using a pub on the Thames, but it might not help much more. Then I thought I'd try explaining it using the Haber process. That was when I realised I'd forgotten what that was a couple of decades ago. In trying to refresh my memory I ran across this link that may be useful. About half way down the page it discusses the importance of equilibrium.

http://www.chemguide.co.uk/physical/equilibria/haber.html

If that doesn't work try some of the other results on googling ["haber process" "dynamic equilibrium"].

Good luck with the exam, though I don't think you'll need it: if equilibrium is your one concern, you've got it beat.

 

Edit: From the same site a good general description:

http://www.chemguide.co.uk/physical/equilibria/introduction.html

[5614]

See if this site:

http://www.bbc.co.uk/schools/gcsebitesize/chemistry/chemicalreactions/3reversiblereactionsrev1.shtml'>http://www.bbc.co.uk/schools/gcsebitesize/chemistry/chemicalreactions/3reversiblereactionsrev1.shtml

Which is specifically designed for GCSE students studying any subjects helps.

 

Go here:

http://www.bbc.co.uk/schools/gcsebitesize/

For info on any GCSE subject.