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A2 OCR Chemistry B F334 - June 2015

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Original post by MathsAddict
Thats what i am doing tbh the big book has too much stuff, i just do a couple past papers and revise what i get wrong. The revise book is excellent the amount of answer they literally copied out of it is amazing.


okay cool ill just do the same. im really scared as im only touching everything now :frown:
Original post by nats927
okay cool ill just do the same. im really scared as im only touching everything now :frown:


Dont be i neglected f334 till today :frown:. i have crap load of other exams to do as well. So i just revise from revise book and do papers and then memorise my notes and revise book.
Been sitting on my laptop since 12 pm going sleep at 12am lool XD. Also never be scared in an exam always approach with logical approach cause u will have learned this stuff before
(edited 8 years ago)
Original post by Welbeck
MISTAKE ON JUNE 2013 F334 MARK SCHEME

Markscheme for Question 1Cii says C=O peak at 1720-1740. But it actually should be C=O peak at 1700-1725. This is because 1720-1740 represents an aldehyde, but it actually should be for a carboxylic acid/carboxylate ion which is at 1700-1725

Feel free to correct my if I am wrong, but I discussed this with 2 chemistry teachers and they both agree


it is between 1720-1740 because earlier in the question is said it was reacted with sodium hydroxide so the carboxlic acid formed will loose its hydrogen atom and there for the C=O will be for an aldheyde
Original post by MathsAddict
Thanks a lot XD even if they do a bad one tbh there has to be someway to do it its just not as a direct answer as usual.

I am adding thread of life notes on to yours after i finish these last two papers.


Exactly! -& that's good!:biggrin: -Omg just had to check if this exam was am or pm! -Pm it turns out, if anyone else is as dopey as me!
Original post by Anonymous696061
Exactly! -& that's good!:biggrin: -Omg just had to check if this exam was am or pm! -Pm it turns out, if anyone else is as dopey as me!


Love PM exams my brains absorbs so much info in the morning so i can look through experiments again.
Original post by MathsAddict
Dont be i neglected f334 till today :frown:. i have crap load of other exams to do as well. So i just revise from revise book and do papers and then memorise my notes and revise book.
Been sitting on my laptop since 12 pm going sleep at 12am lool XD. Also never be scared in an exam always approach with logical approach cause u will have learned this stuff before


is it bad that i havent done any papers yet?
and ill tryy not tooo
For hydrolysis of amides and esters is it dilute HCL or moderately concentrated? 😃
Do you think they could ask us a 6 marker on sodium thiosulfate titrations? (Like they do with the potassium manganate ones)?
Possible points I have area
- used to work out concentration of oxidising agent
-reacted with iodide ions
- iodide oxidised to iodine and oxidising agent is reduced
- iodine produced is titrated with sodium thiosulfate
- sodium thiosulfate is oxidised and iodine is reduced
- add starch to see end point
- titration gives volume of unreacted iodine

Is this everything? I really hope this type of titration doesn't come up I hate it :frown:
Original post by Turtlefushsia
For hydrolysis of amides and esters is it dilute HCL or moderately concentrated? 😃


Moderately, e.g. 4 moldm-3
Original post by nats927
is it bad that i havent done any papers yet?
and ill tryy not tooo


At all like all year? You should have done it at least once and if you're aiming high at least twice each one.
Original post by radhikagulati
Do you think they could ask us a 6 marker on sodium thiosulfate titrations? (Like they do with the potassium manganate ones)?
Possible points I have area
- used to work out concentration of oxidising agent
-reacted with iodide ions
- iodide oxidised to iodine and oxidising agent is reduced
- iodine produced is titrated with sodium thiosulfate
- sodium thiosulfate is oxidised and iodine is reduced
- add starch to see end point
- titration gives volume of unreacted iodine

Is this everything? I really hope this type of titration doesn't come up I hate it :frown:


Is this from a mark scheme? I hate titrations tbh
Original post by Anonymous696061
Exactly! -& that's good!:biggrin: -Omg just had to check if this exam was am or pm! -Pm it turns out, if anyone else is as dopey as me!


Do you have bullet points for the process of doing a titration, its the practical technique i'm least familiar with and I don't think its in the notes you made? The notes are great btw so thanks! :smile:
To break ester bonds it moderately concentrated s2o4 right? and for amide its conc?

like on the M/S sometimes its moderately and it says not to accept concentrated and sometimes concentrated .
Original post by MathsAddict
At all like all year? You should have done it at least once and if you're aiming high at least twice each one.


i mean recently.. ahh im stressing ill probably have no sleep tonight
Original post by MathsAddict
Is this from a mark scheme? I hate titrations tbh


No a 6 marker on this type of titration (its always been the potassium manganate ones) hasn't come up yet so I'm just brainstorming possible marking points just in case OCR decide to be really nasty (which they are -__-)

Is there anything else that can be added to what Ive said?
Original post by suyoof123
To break ester bonds it moderately concentrated s2o4 right? and for amide its conc?

like on the M/S sometimes its moderately and it says not to accept concentrated and sometimes concentrated .


To make an ester you use concentrated but to break it in acid hydrolysis, you use moderately concentrated
Original post by radhikagulati
To make an ester you use concentrated but to break it in acid hydrolysis, you use moderately concentrated


Thanks, what about amide breakage under acid conditions, its concentrated right?
How do you answer questions like these ? How do you know how large Kc needs to be in order for it to be on a certain position ?
ImageUploadedByStudent Room1433879965.711653.jpg


Posted from TSR Mobile
Original post by suyoof123
Thanks, what about amide breakage under acid conditions, its concentrated right?


Moderately concentrated again for amides
Original post by suyoof123
Thanks, what about amide breakage under acid conditions, its concentrated right?


I thought is was moderately conc?

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