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    (Original post by mil88)
    was that f324 or f325?
    f324, haven't done 2015 f325 yet
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    Hoping to get the A* in Chemistry! A bit of a stretch really, considering Chemistry exams = the impossible...
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    Hey guys, how were your AS?

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    Anyone here actually understand acids, bases and Buffers?
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    (Original post by BrownGuyIrfan)
    Anyone here actually understand acids, bases and Buffers?
    I think once you understand constants from rates and equilibria then acids bases and water become easier to understand, I made a mind map where I showed all the relationships between the constants and this helped me with my calculations, I could attach a picture of it if you think it would help you?
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    (Original post by micaela_m)
    I think once you understand constants from rates and equilibria then acids bases and water become easier to understand, I made a mind map where I showed all the relationships between the constants and this helped me with my calculations, I could attach a picture of it if you think it would help you?
    I find the Buffer calculations really difficult, working out the pH of weak acids or whatever that stuff is really easy. To be honest i'm open to looking at anything really becuase i'm desperate so if it isn't too much trouble I'd love to see the mind map
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    (Original post by micaela_m)
    I think once you understand constants from rates and equilibria then acids bases and water become easier to understand, I made a mind map where I showed all the relationships between the constants and this helped me with my calculations, I could attach a picture of it if you think it would help you?
    That would be very helpful!! :P
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    (Original post by BrownGuyIrfan)
    I find the Buffer calculations really difficult, working out the pH of weak acids or whatever that stuff is really easy. To be honest i'm open to looking at anything really becuase i'm desperate so if it isn't too much trouble I'd love to see the mind map
    I have looked for mine and unfortunately I cannot find it anywhere (my school flooded so I may have lost it) but I will ask the others in my class if they have one because we all made them and post it if it is found. However I found some on the internet that were slightly helpful but not as clear as the one I originally had in mind- I'll keep looking for it anyhow.
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    (Original post by micaela_m)
    I have looked for mine and unfortunately I cannot find it anywhere (my school flooded so I may have lost it) but I will ask the others in my class if they have one because we all made them and post it if it is found. However I found some on the internet that were slightly helpful but not as clear as the one I originally had in mind- I'll keep looking for it anyhow.
    My friend in the class has her map. I'm attaching it, hope it helps!
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    Hi I'm doing ocr chem. Unfortunately, got a D last year. But I have high hopes this year, because I'm redoing f321 and f322 and f332( AS Coursework-which I already retook a month ago). So apparently my grade for AS might bump by two. For A2 I'm doing way better than AS last year. Kinda lost my hopes on Jan when i did the f324 2015 paper and the nmr spec was a large and complicated molecules. Advice for those that are still doing chem and weren't satisfied with their AS grade- seriously there was a girl at my school last year who moved from D to A by repeating all modules and putting lots of effort... So never give up all of ya!
    by the way last year's F325 had the highest grade boundary since jan 2010 f325 , this indicates that the F325 paper was better than the June 2015 F324(THE NIGHTMARE). Haven't done the F325 june 15 paper but I'm doing it after the holidays as a mock.
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  1. File Type: pdf Grade Boundaries - OCR Chemistry A A2.pdf (29.9 KB, 270 views)
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    (Original post by safhassan)
    Hi I'm doing ocr chem. Unfortunately, got a D last year. But I have high hopes this year, because I'm redoing f321 and f322 and f332( AS Coursework-which I already retook a month ago). So apparently my grade for AS might bump by two. For A2 I'm doing way better than AS last year. Kinda lost my hopes on Jan when i did the f324 2015 paper and the nmr spec was a large and complicated molecules. Advice for those that are still doing chem and weren't satisfied with their AS grade- seriously there was a girl at my school last year who moved from D to A by repeating all modules and putting lots of effort... So never give up all of ya!
    by the way last year's F325 had the highest grade boundary since jan 2010 f325 , this indicates that the F325 paper was better than the June 2015 F324(THE NIGHTMARE). Haven't done the F325 june 15 paper but I'm doing it after the holidays as a mock.
    I'm similar to you, I got a C at AS and I am resitting f322 and AS coursework. I need a B for my uni offer but they only allow me to resit modules of the AS rather than the full AS. I am doing a lot better at A2 than I did last year however the june 15 f324 paper really scared me, we did it as a mock and I got an E, this was really far off my target so I am slightly worried but I have put a lot more effort in since into past papers so hopefully it goes a lot better this summer!
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    (Original post by micaela_m)
    I'm similar to you, I got a C at AS and I am resitting f322 and AS coursework. I need a B for my uni offer but they only allow me to resit modules of the AS rather than the full AS. I am doing a lot better at A2 than I did last year however the june 15 f324 paper really scared me, we did it as a mock and I got an E, this was really far off my target so I am slightly worried but I have put a lot more effort in since into past papers so hopefully it goes a lot better this summer!
    Guys don't let the June 2015 paper scare you. Last year in my mock I did the June 2014 paper in December and got an E. In the actual exam (I did the June 2015 paper for my actual exam) I got an A... That just proves its possible.

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    (Original post by BrownGuyIrfan)
    Anyone here actually understand acids, bases and Buffers?
    Yes
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    I recommend the alevelchemistry website, has past papers on each topic on OCR, aiming to do all for each topic! Good practise!
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    Does anyone here have access to the 2015 chemistry papers, as I would like to do them for practice?
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    Hey.
    Is this thread for OCR A or B?
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    (Original post by SamuelN98)
    Hey.
    Is this thread for OCR A or B?
    OCR A
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    Can someone help with this question please:

    A 25.0 cm3 portion of a solution containing Fe2+ and Fe3+ ions was acidified and titrated against potassium permanganate (VII) solution. 15.0 cm3 of a 0.0200 mol dm-3 solution of potassium manganate (VII) were required. A second 25.0cm3 portion was reduced with zinc and titrated against the same manganate solution. This time 19.0cm3 of the oxidant was required.
    a) calculate the concentrations of Fe2+ and Fe3+ ions in the solution
    b) what percentage of the total iron content of the solution was Fe3+

    So far I've done:
    MnO4- + 8H+ + 5Fe2+ ---> Mn2+ + 4H2O + 5Fe3+
    mole of MnO4 = 3x10-4 mol and mole of Fe2+ = 1.5x10-3 mol (1:5 mole ratio)
    concentration of Fe2+ = 0.06 moldm-3

    I have no idea how to work out the concentration of Fe3+
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    Completely failing the practicals this year
    I got an A overall last year so only needed a B in my exams, but I'm currently on a D in my practicals and I honestly don't know what I'm doing wrong that I keep getting low marks
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    I've got f324 in the bag tbh, literally only have to do NMR, I'm focusing on that until I am confident, and only then will I start worrying about f325 . Though F325.. I really need to step my game up.
 
 
 
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