AS Level Chemistry (Edexcel) Unit 1 and 2 (May 23rd and 27th 2011)

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giraffegiraffe
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People can share notes/advice here :-)


Does anyone have any notes on polarity or intermolecular forces? thanks!
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Miller693
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I would recommend docbrown or chemguide (just google them) for easy to understand notes and stuff. Not looking forward to this exam, it's probably my worst one!!
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LuckyDuck
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Doing both these exams.What are the topics you guys find most difficult?
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LuckyDuck
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(Original post by giraffegiraffe)
me too! thanks, chemguide especially was quite good . i have been relying on cgp so far which seems quite good for understanding concepts but i keep getting mixed up. what other exams do you have? there is just so much that there doesnt seem to be enough time to it all properly!?



remembering the alchohols/halogens/halogenoalkane/group 1 & 2 reactions i find the hardest! drawing mechanisms etc? also find it hard to remember all the specific words. what about you?
The organics section is ok. It's more about understanding it than memorising. I'm expecting there to be quite a bit of organics as the Jan paper was based heavily on Inorganics, which I hated.
What other exams are you taking?
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giraffegiraffe
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I have got statistics on friday, biology next week also as well as these 2 chemistry ones, i will be glad when they are done! i have maths and french papers too but they are (thankfully) a while away. What about you?

I haven't got the jan 11 paper, I'll have a look for it. I've hardly done any chemistry papers so far which I need to. what sort of topics do you think will come up based on that one?

a quick question ..... what is the difference between polarising ions in unit 1 (which makes an ionic bond have covalent character) and electronegativeity in unit 2 (atoms like fluorine can pull the bonding electrons in a covalent bond towards itself) ?? Do polarising ions also pull electrons towards itself?
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seanmahoward
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(Original post by giraffegiraffe)
I have got statistics on friday, biology next week also as well as these 2 chemistry ones, i will be glad when they are done! i have maths and french papers too but they are (thankfully) a while away. What about you?

I haven't got the jan 11 paper, I'll have a look for it. I've hardly done any chemistry papers so far which I need to. what sort of topics do you think will come up based on that one?

a quick question ..... what is the difference between polarising ions in unit 1 (which makes an ionic bond have covalent character) and electronegativeity in unit 2 (atoms like fluorine can pull the bonding electrons in a covalent bond towards itself) ?? Do polarising ions also pull electrons towards itself?
Well they are similar, its all down to Charge/mass ratio (charge density) it also follows through to the stability of groupe one and two nitrates and carbonates, The higher an atoms charge density, the more polarising it is, thierfore pulling the electron cloud and distorting it, due to flourines charge density it forms hydrogen bonds in HF whereas the rest of the halogens only form dipole - dipole interactions and van der waals. So yes the more "polarising" an ion the greater the charge density and the greater the distortion of the ionic compound, Hope that Helped, Oh and electronegativity is dependant on charge density, higher the charge density higher the electronegativity (higher tendancy to pull electrons towards it)
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giraffegiraffe
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(Original post by seanmahoward)
Well they are similar, its all down to Charge/mass ratio (charge density) it also follows through to the stability of groupe one and two nitrates and carbonates, The higher an atoms charge density, the more polarising it is, thierfore pulling the electron cloud and distorting it, due to flourines charge density it forms hydrogen bonds in HF whereas the rest of the halogens only form dipole - dipole interactions and van der waals. So yes the more "polarising" an ion the greater the charge density and the greater the distortion of the ionic compound, Hope that Helped, Oh and electronegativity is dependant on charge density, higher the charge density higher the electronegativity (higher tendancy to pull electrons towards it)
THANKYOU! so an atom which has high electronegativity has a high polarising ability?
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seanmahoward
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(Original post by giraffegiraffe)
THANKYOU! so an atom which has high electronegativity has a high polarising ability?
yep , if you are trying to find out how polarising a groupe of ions are, take a look at thier ionic radius, and thier charge. so as you go down groupe 1 the radius increases but the charge stays the same, so the further you go down groupe one the lesser the charge density hence lesser electronegativity
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giraffegiraffe
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(Original post by seanmahoward)
yep , if you are trying to find out how polarising a groupe of ions are, take a look at thier ionic radius, and thier charge. so as you go down groupe 1 the radius increases but the charge stays the same, so the further you go down groupe one the lesser the charge density hence lesser electronegativity
THANKYOU :-D this cleared up a lot
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seanmahoward
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(Original post by giraffegiraffe)
THANKYOU :-D this cleared up a lot
No problem
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Robert McGeachan
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Yeah Im sitting Unit two working my arse off for it by far the hardest A-level I have taken what have people got on assessed practicals im on 39/40 unit one i got like 92ums but made stupid mistakes hoping to get a hundred ums on this for the amount of work I have done for it slightly rejected other subjects haha....Yeah im completely agree on getting confused between grp 1&2 and the organic halogenalkane and alcohol reactions really difficult to get my head round.
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seanmahoward
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(Original post by Robert McGeachan)
Yeah Im sitting Unit two working my arse off for it by far the hardest A-level I have taken what have people got on assessed practicals im on 39/40 unit one i got like 92ums but made stupid mistakes hoping to get a hundred ums on this for the amount of work I have done for it slightly rejected other subjects haha....Yeah im completely agree on getting confused between grp 1&2 and the organic halogenalkane and alcohol reactions really difficult to get my head round.
What do you mean confused between groupe 1 and 2?
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Robert McGeachan
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Just the Reactions of oxides and with water then solubility of sulphates and hydroxides and like decomp of nitrates carbonates e.t.c but i think i get them now just meant at first I found it different to differentiate between all of them
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Dima.K
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Im doing both next week too

Ive made some chem unit 2 two notes, theyre on the getrevising website:

http://getrevising.co.uk/resources/a...y_unit_2_notes

Hope you find them useful.
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seanmahoward
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http://www.knockhardy.org.uk/ppoints.htm
Under organic chemistry groupe II look at that powerpoint amazing powerpoints on this website if u havent seen it yet
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Robert McGeachan
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No i havent cheers mate
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LiberiFatali
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Don't forget to get in a decent amount of past paper practice before Monday guys. If I did more papers first time around I wouldn't be needing to sit these papers again :-(
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Robert McGeachan
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(Original post by LiberiFatali)
Don't forget to get in a decent amount of past paper practice before Monday guys. If I did more papers first time around I wouldn't be needing to sit these papers again :-(
Yeah definitley, do you do the old syllabus nuffield papers of just the new ones because there arent that many and i dont know if the old ones are any good?
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giraffegiraffe
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(Original post by Robert McGeachan)
Yeah definitley, do you do the old syllabus nuffield papers of just the new ones because there arent that many and i dont know if the old ones are any good?
i am planning on sticking to the new ones (to look at mark schemes etc and the specific words they use i think it may be better? but even if you are looking through old papers etc i guess it is all good practice.

how is everyones revision going?
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giraffegiraffe
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(Original post by seanmahoward)
http://www.knockhardy.org.uk/ppoints.htm
Under organic chemistry groupe II look at that powerpoint amazing powerpoints on this website if u havent seen it yet

this seems really useful cheers! (and much better than staring at a page of a book trying to learn them)
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