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

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    I lost like 6 marks (that I know of) and they were all silly mistakes. I feel you
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    (Original post by GetOverHere)
    I did this too. I was thinking about not putting arene because I thought it'd be too vague, but then finally decided to commit.
    Also, you got 3 chiral carbons for the tripeptide right? 3rd C being on the R group
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    (Original post by 24u5owehjr34uoer)
    also was the octadeconoic acid Q 2 marks?

    if so, whats the marking criteria for that?

    Surely they award a mark for the correct interchangable C=C right?

    I was under so much pressure that i left the COOH group in the process of drawing that annoying isomer
    I think it'd be 1 for the COOH, and another for the correct double bond, then perhaps they'll limit you to one if you didn't draw it skeletally.
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    (Original post by MrOlaftheSnowman)
    Possibly. No-one can actually say because the mark scheme may said 'allow polypeptide.' But the correct answer is poly amide
    I don't think so because polypeptide is only for amino acids
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    (Original post by 24u5owehjr34uoer)
    Also, you got 3 chiral carbons for the tripeptide right? 3rd C being on the R group
    Yep, 2 come from the 2 central carbon atoms on the 2 amino acids that weren't glycine, and then the one that wasn't aspartic acid or glycine had one that was bonded to H, CH3, CH2CH3 and the rest of the tripeptide.
    • Welcome Squad
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    Welcome Squad
    I didn't like the lactic acid questions- especially the one about stitches!
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    For the first question it was the THIRD fatty acid. The question asked which is 'most LIKELY' to cause heart disease. The third fatty acid is most LIKELY to have at least one trans bond, and therefore most likely to be a trans fatty acid. It is TRANS FATTY ACIDS that act like SATURATED FATS. Key point to note here is there is a difference between TRANS FATS and TRANS FATTY ACIDS.
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    (Original post by GetOverHere)
    I think it'd be 1 for the COOH, and another for the correct double bond, then perhaps they'll limit you to one if you didn't draw it skeletally.
    Ah, I drew it skeletally ( interchangable too) but just forgot the COOH, everything was correct apart from the damn COOH lol
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    (Original post by Cal 1)
    For the first question it was the THIRD fatty acid. The question asked which is 'most LIKELY' to cause heart disease. The third fatty acid is most LIKELY to have at least one trans bond, and therefore most likely to be a trans fatty acid. It is TRANS FATTY ACIDS that act like SATURATED FATS. Key point to note here is there is a difference between TRANS FATS and TRANS FATTY ACIDS.

    Idk man... how many marks was it? 2 right?
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    (Original post by 24u5owehjr34uoer)
    Ah, I drew it skeletally ( interchangable too) but just forgot the COOH, everything was correct apart from the damn COOH lol
    I think you may not get the marks if I'm honest, because the name is dependent on where the double bond is situated, and because the counting starts from the COOH part, it's unclear which end is where your COOH would have been, if that makes sense? I may be wrong but that's what it seems like to me.
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    what would happen if you drew the correct compound in the wrong box
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    (Original post by 24u5owehjr34uoer)
    Idk man... how many marks was it? 2 right?
    1 /5char
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    (Original post by 24u5owehjr34uoer)
    Idk man... how many marks was it? 2 right?
    The stearic acid was a saturated fatty acid so it is more unhealthy.
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    For the Proton NMR question when you had to fill in the table what did everyone get?? I didnt really know how to do it and cant remember but i think my asnwers involved 3 3 and 2 for the three relative peak areas... is that even close to correct?
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    (Original post by GetOverHere)
    1 /5char
    1 /5char?
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    (Original post by Randall13)
    The stearic acid was a saturated fatty acid so it is more unhealthy.
    False. Saturated fats are bad. Not necessarily saturated fatty ACIDS. Trans fatty acids are bad. Doesn't mention about saturated fatty acids.
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    (Original post by Cal 1)
    For the first question it was the THIRD fatty acid. The question asked which is 'most LIKELY' to cause heart disease. The third fatty acid is most LIKELY to have at least one trans bond, and therefore most likely to be a trans fatty acid. It is TRANS FATTY ACIDS that act like SATURATED FATS. Key point to note here is there is a difference between TRANS FATS and TRANS FATTY ACIDS.
    but the first acid was saturated so surely that would be the most likely
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    What do people think 54/60 will get me? I'm thinking 85/90 UMS?
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    (Original post by hbk1)
    but the first acid was saturated so surely that would be the most likely
    Re-read what I wrote, but pay particular attention to the fact that saturated fats(which are bad) and saturated fatty acids are different.
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    (Original post by hbk1)
    but the first acid was saturated so surely that would be the most likely
    I remember in a past paper is asked why the Triglyceride was bad and the answer was "One of the fatty ACIDS are Trans." Hence, if we extrapolate that logic to this exam question, it is the Saturated Fatty Acid as that is the only fatty acid that can end up causing a saturated fat that definitely increases risk of CHR. The Unsaturated Fatty Acid will not necessarily form a TRANS Fat and hence the third fatty acid is wrong. The First Fatty acid is right.
 
 
 
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