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OCR B F335 - Chemistry by Design - 13th June 2012

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Original post by Bi0logical
If you have the OCR Salters revision guide, there's a page with a list of synoptic stuff u need to know.
It's mainly the basics; electron config, different types of bonding, shapes, affects of catalyst/rate, etc etc


A2 revise revision guide?...and what page mate
Original post by master_blaster66
A2 revise revision guide?...and what page mate


page 82 :biggrin:
Anyone got easy way to remember the buffer calcs and rearranging?
Buffers in action;
Carbon Dioxide is dissolved in oceans and limestone rocks (mainly calcium carbonate) act together as a buffering system. The "carbonic acid" produced acts as a weak acid and the limestone acts as an anion (CO32-) sink.
This means that as atmospheric CO2 increases and dissolves to form carbonic acid, the pH can be maintained.
for the last question on the jan 2012 F335 paper does anyone know how to get the pH.
Reply 265
Original post by minip12qss
for the last question on the jan 2012 F335 paper does anyone know how to get the pH.


can you post a link to the paper and mark scheme so i can help? :smile:
Can someone ask me random questions please
F335 Jan 12 MS.pdfF335 Jan 12.pdf
I think its attached btw its the last question
Original post by minip12qss
F335 Jan 12 MS.pdfF335 Jan 12.pdf
I think its attached btw its the last question


i remember this was a tough question, i was doing this pastpaper a few days ago
Original post by master_blaster66
i remember this was a tough question, i was doing this pastpaper a few days ago


did you work out how to do it
46g of Methanoid acid vapor are found to occupy 16dm3 at 120degrees and room pressure.
Suggest an explanaition for these data. Include full structural formula in your answer.
One mole of gas molecules of a gas at 120degrees and room pressure occupies 32dm3
Reply 271
Original post by Bi0logical
46g of Methanoid acid vapor are found to occupy 16dm3 at 120degrees and room pressure.
Suggest an explanaition for these data. Include full structural formula in your answer.
One mole of gas molecules of a gas at 120degrees and room pressure occupies 32dm3


This one got me. It's double what you expect from a methanoic acid molecule, so there has to be two, joined by hydrogen bonds... and you have to know that you should draw a diagram of two molecules hydrogen bonded.
Charge on the hydrogen in; 2B(OH)3 ??
Original post by master_blaster66
...


I did the paper you told me to do, I got 94, I made loads of silly mistakes though... It was a fairly tough paper, but nothing spectacularly hard.
Original post by navarre
This one got me. It's double what you expect from a methanoic acid molecule, so there has to be two, joined by hydrogen bonds... and you have to know that you should draw a diagram of two molecules hydrogen bonded.

ooo I was very close, I wrote something about only 1 mole of methanoic acid occupying 16dm3, because rfm 46/46 = 1.
that is one of the most difficult question I came across, it's not actually hard, you just dont know what its asking you and they dont make it clear :angry:
Original post by Ilyas
I did the paper you told me to do, I got 94, I made loads of silly mistakes though... It was a fairly tough paper, but nothing spectacularly hard.


Nothings hard for you bro :wink:
does anybody want to revise over MSN?
Reply 277
Original post by Bi0logical
ooo I was very close, I wrote something about only 1 mole of methanoic acid occupying 16dm3, because rfm 46/46 = 1.
that is one of the most difficult question I came across, it's not actually hard, you just dont know what its asking you and they dont make it clear :angry:


Exactly. You just have to guess that they want you to show two hydrogen bonded methanoic acid molecules. I'd never seen a question like that before, but tbh, at least we've seen it now, so if in the exam they ask a similar one, we'll have some clue.
Reply 278
Original post by Bi0logical
If you have the OCR Salters revision guide, there's a page with a list of synoptic stuff u need to know.
It's mainly the basics; electron config, different types of bonding, shapes, affects of catalyst/rate, etc etc


So it's basically all of AS knowledge except some specific detail relating to certain topics (Developing fuels etc). :biggrin:
Reply 279
Original post by Iepnauy
So it's basically all of AS knowledge except some specific detail relating to certain topics (Developing fuels etc). :biggrin:


exactly that :tongue:

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