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

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Original post by Kaz_96
I got 195 for that part 3 LOL the bromine q entirely was v tricky


Not sure 195 was right. I got 69.


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Original post by Kwaks
What did you put for the rate equation? Also what did you put for effect on results if the volatile substances are lost. I put it makes the rate appear after than it actually is.....


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Rate equation I got first first and second order respectively, and the volatile one I said it wouldn't change the rate because the ratio of concentrations would still be the same, bullsh*tted basically because I had no clue
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Kwaks
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Original post by chloewilliamsss
Rate equation I got first first and second order respectively, and the volatile one I said it wouldn't change the rate because the ratio of concentrations would still be the same, bullsh*tted basically because I had no clue


I said it would appear faster than it actually is because there are less reactants and so they are used up quicker. 😭


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Original post by chloewilliamsss
What answers did you put for the 5 marker about the red brown precipitate and rusting?

Fe2+ is oxidised to Fe3+ by the airFe2+ => Fe3+ + e-This makes all the iron become Fe3+They all react with the -OH ion like so:Fe3+ + 3OH- => Fe(OH)3 (s)Iron(iii) hydroxide is a red brown precipitate.Something like that but with better English 😊
(edited 7 years ago)
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Bruhh
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Original post by shooting_stars
I got 195 for the 1st 2 marker of the bromine numbers questions


I got 390 for that,

Anyone else really dislike this paper? Where were the transition metals/complexes at?!
That whole paper was really tough. Needed 75 UMS to go into paper 2 on an A, probably got about 67 UMS :/
Original post by Invincibles
Not sure 195 was right. I got 69.


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pretty sure it was 195
Original post by jack.lp.thompson
Fe2+ is oxidised to Fe3+ by the airFe2+ => Fe3+ + e-This makes all the iron become Fe3+They all react with the -OH ion like so:Fe3+ + 3OH- => Fe(OH)3 (s)Iron(iii) hydroxide is a red brown precipitate.Something like that but with better English 😊


yeh I put that also
was a good paper but messed up the bromine question completely...
Original post by chloewilliamsss
Rate equation I got first first and second order respectively, and the volatile one I said it wouldn't change the rate because the ratio of concentrations would still be the same, bullsh*tted basically because I had no clue


I put first order for both. The rate never quadrupled so it cant be second order
Guesses of grade boundaries?? Was the hardest paper out of all the years by far!!
Original post by Tremerz
Guesses of grade boundaries?? Was the hardest paper out of all the years by far!!


65 for an A, tricky paper but roughly similar to june 2015 in terms of difficulty imo
Original post by Daniel9998
I put first order for both. The rate never quadrupled so it cant be second order


It never quadrupled because the two of them halved and the third doubled with the rate staying the same so it was second order
Hi, did anyone also get 7 for bromine number, worth 5 marks, in the f334 exam?
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


urgh that was only 1 mark right?
Original post by Daniel9998
65 for an A, tricky paper but roughly similar to june 2015 in terms of difficulty imo


You think? I found it much harder than last years one. The iodine question was tricky, and the wording of a few other questions could lower the grade boundary. Also the fact that it was mostly all new types of questions and none the same style as previous years.
Original post by Tremerz
You think? I found it much harder than last years one. The iodine question was tricky, and the wording of a few other questions could lower the grade boundary. Also the fact that it was mostly all new types of questions and none the same style as previous years.


Yeh could be lower, who knows tbh.
Original post by Daniel9998
Yeh could be lower, who knows tbh.


Messed up the iodine question... which made me rush the rest of the paper. Just hope they are low enough haha :smile:
Original post by ben_tyler28
Hi, did anyone also get 7 for bromine number, worth 5 marks, in the f334 exam?


Yes it was seven. 6.56 rounded up

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Is it just me that found this paper ridiculously hard? So frustrating. Anyone else not answer the calculation either?

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