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OCR Chemistry B (Salters) F334/F335 Exam Thread 2016 (14th/22nd June)

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Original post by lucyyyyy0
Wouldn't the transition metal ion be surrounded by Aqua Ligands forming a complex ion which then undergoes ligand substitution to form the precipitate?


no because it talked about if it was exposed to air
Anyone wanna get an unofficial mark scheme going if they're confident enough with their answers? I would, but I didn't get much correct i think loool.
Original post by Daniel9998
did everyone else draw 4 different molecules for the E/Z isomers?
I did!
Original post by Daniel9998
did everyone else draw 4 different molecules for the E/Z isomers?


I thought it was 3,

EZ
EE
ZZ

The ZE was just the EZ flipped

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Reply 244
Do you guys think the grade boundaries will be about the same as last year?
Original post by Zuzuvela
Grade boundaries should be around 56 for an A. That's not unreasonable considering the paper Look at how many of the questions had not come up before in any way shape or form. First time I've seen cold drawing, First time I've seen 10marks worth of maths in one question (bromine number). First time recrystallisation has ever been 3 marks. First time heterogeneous catalysis has been asked. First time that we have been asked to show something is in excess.First time that I've seen a 5 mark question on rusting iron and been given 3 lines to put it on. It's an absolute disgrace of a paper and some action will have to be taken if the grade boundaries do not reflect it's difficulty. OCR if you are reading this then its not to say go and make F335 easy to make up for your questions. Make it like you do every year, so that those who work hard get what they deserve.

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Cannot rep this post enough!!
Reply 246
Original post by Daniel9998
did everyone else draw 4 different molecules for the E/Z isomers?


i did :smile:
Original post by Zuzuvela
I thought it was 3,

EZ
EE
ZZ

The ZE was just the EZ flipped

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It probably won't make a difference if youve drawn three or four as two were the same molecules so will probably be 'ignore'
Original post by Tremerz
Messed up the iodine question... which made me rush the rest of the paper. Just hope they are low enough haha :smile:


What was the iodine question??
Original post by Ligand
I drew 3 isomers because the isomer with one E and one Z double bond could just be reflected to get the isomers which has the E and Z's the other way round. Did anyone else put three because one of them could just be reflected in a mirror to get the other one?


Yes mate, I'm guessing the 4th mark was labeling them. It really should have been 5 marks for recognising that because that can take a minute of your time

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Original post by Zuzuvela
I thought it was 3,

EZ
EE
ZZ

The ZE was just the EZ flipped

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oh ffs, losing too many marks now
Original post by Motin
Do you guys think the grade boundaries will be about the same as last year?


lower than last year
Original post by Amyfrancis97
It probably won't make a difference if youve drawn three or four as two were the same molecules so will probably be 'ignore'


I really hope so
Original post by IBerrr
I got 10g as my final answer btw


Yeah I've seen everyone else got 7 too. How did you do it?
Original post by lucyyyyy0
Wouldn't the transition metal ion be surrounded by Aqua Ligands forming a complex ion which then undergoes ligand substitution to form the precipitate?
As the spec only says you need to know about [Fe(H20)6]2+ and [Fe(H20)6]3+ for iron complexes, I doubt it! But who knows!! 😄
Reply 255
Original post by Aspire7736
It never quadrupled because the two of them halved and the third doubled with the rate staying the same so it was second order


If the third one doubled and the rate stayed the same, isn't it 0 order????


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Reply 256
Original post by Daniel9998
I put zinc

Acts as a salt bridge


Damn I put acts as salt bridge but then crossed it out and said allows current to flow, did this because the only ions mentioned in the entire question were those in the half-cell and those aren't supposed to mix. I'm pretty sure ur right though
Original post by James476
What was the iodine question??


There was no iodine question it was bromine numbers it got everyone confused. I've heard of iodine number before but not bromine. And correct me if I'm wrong but iodine numbers aren't F334 anyway. Either f331 or F335

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Original post by Zuzuvela
Grade boundaries should be around 56 for an A. That's not unreasonable considering the paper Look at how many of the questions had not come up before in any way shape or form. First time I've seen cold drawing, First time I've seen 10marks worth of maths in one question (bromine number). First time recrystallisation has ever been 3 marks. First time heterogeneous catalysis has been asked. First time that we have been asked to show something is in excess.First time that I've seen a 5 mark question on rusting iron and been given 3 lines to put it on. It's an absolute disgrace of a paper and some action will have to be taken if the grade boundaries do not reflect it's difficulty. OCR if you are reading this then its not to say go and make F335 easy to make up for your questions. Make it like you do every year, so that those who work hard get what they deserve.

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yeh should be but I doubt it will be. Id be surprised if its anything less than 63
Original post by Daniel9998
no because it talked about if it was exposed to air


Yes, but it said it was in solution 😊

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