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OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD watch

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    (Original post by 24u5owehjr34uoer)
    nah, i analysed the jan 2013 paper, 90% identical to our 2016 paper.


    It will realistically be:

    59; MAX
    55; A*
    51; A
    47: B
    43; C

    PS; this is jan 2013's boundaries :P

    If i was a betting man, A will no doubt be 50+/60
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    anyone have an unofficial mark scheme?
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    (Original post by jadder1224)
    guys, I put 2-hydroxycarboxylic acid for the systematic name will i lose a mark?
    It was 2-hydroxypropanoic acid, so yeah, lost that one I'm afraid
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    Any decent unofficial mark scheme?
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    Name:  IMG_3327.jpg
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    Points (5) and (7) : does this mean you could actually have chosen any of the fatty acids, as long as you justified it correctly?
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    (Original post by RBoss)
    If you quoted the exact range possible, you'd get the marks I'd say
    I did that and also stated the type of environment ie R-CH, HC-N and HC-O next to my range.
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    (Original post by huwgerard1)
    For the question about synthetic vs fermentation, do i have to state that synthetic produces TWO optical isomers?
    I just said that synthetic produces a mix of isomers where as the fermentation only produces one.
    Also, with the lactic acid dissolving, i only mentioned the OH from COOH Forming H bonds! I completely lost sight of the other OH group. Is this a mark lost?
    I felt so confident... coming on here wasnt a good idea!
    I said it "is a mix of two optical isomers" just because on the 2015 paper it said you had to specifically say 4 optical isomers. Then again that may heve been because it stated in the question 25% chance.
    And I'm sure for putting -OH you'll get at least one or two marks, one for a functional group and one for hydrogen bonding?
    Don't worry about it, people on the student room get it wrong too you know, last year I convinced myself I'd lost 20 marks on the second biology paper because of this site but I hadn't…
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    Did it matter in which order the peptides were bonded?
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    If I made the mistake of placing the ketone on the wrong carbon but carried on my error throughout the rest of the question how many marks out of 7 would I get...
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    (Original post by KATIE6464646464)
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    Points (5) and (7) : does this mean you could actually have chosen any of the fatty acids, as long as you justified it correctly?
    It said more likely so I assume it's the saturated one, because the other two may have had cis configuration?


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    (Original post by jamesgates1)
    Did it matter in which order the peptides were bonded?
    naa it shouldn't matter
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    Mark scheme: https://goo.gl/gEi388
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    (Original post by k.russell)
    For the chromatography question, is the answer not;
    Similar compounds will appear in the same spot on the chromatography plate
    This is because they have similar physical properties e.g. volatility, adsorption to stationery phase, solubility in mobile phase
    The similar physical properties are caused by similar molecular structures and similar functional groups in the molecular structure
    You forgot the first part to the question which asked "explain how an amino acid can be identified from TLC"
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    (Original post by 24u5owehjr34uoer)
    nah, i analysed the jan 2013 paper, 90% identical to our 2016 paper.


    It will realistically be:

    59; MAX
    55; A*
    51; A
    47: B
    43; C

    PS; this is jan 2013's boundaries :P
    you do notice there are only 4 questions in jan 2013, and 6 for this years. and the hard questions all only appear in this paper.
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    I drew the secondary alcohol like this is it right? Name:  image.jpg
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    (Original post by CalistaJupiter)
    I said it "is a mix of two optical isomers" just because on the 2015 paper it said you had to specifically say 4 optical isomers. Then again that may heve been because it stated in the question 25% chance.
    And I'm sure for putting -OH you'll get at least one or two marks, one for a functional group and one for hydrogen bonding?
    Don't worry about it, people on the student room get it wrong too you know, last year I convinced myself I'd lost 20 marks on the second biology paper because of this site but I hadn't…
    Thank you so much for your reply i remeber that 2015 question - gutted i forgot to put two fingers crossed for us both!!
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    (Original post by drandy76)
    It said more likely so I assume it's the saturated one, because the other two may have had cis configuration?


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    Yeah maybe .. but if i said that because of the C=C that is could be a trans fat, therefore it could increase bad cholesterol etc. etc. surely it's correct as well?

    Probably should have just said the first one to be safe!
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    (Original post by lai812matthew)
    you do notice there are only 4 questions in jan 2013, and 6 for this years. and the hard questions all only appear in this paper.
    I'd also like to point out that although the questions were straight forward, there was a lot of never-before-sone stuff.. Like who expected that last question instead of the usual NMR? And the stuff about stitches, and more wordy questions… I think he grade boundaries may be like 53 for A* and 49 for A
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    (Original post by drandy76)
    It said more likely so I assume it's the saturated one, because the other two may have had cis configuration?


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    yes i think is the first one, cause naturally occurring fats are mostly cis, so the first one have the greatest chance to produce trans fats as it have the most C-C bond out of all three. gutted that I got wrong because of not thinking at all.
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    Also I got propanoic acid for compound H, but I didn't show much working out? Will I still get the marks
 
 
 
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