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OCR Chemistry A Exam Thread (Breadth - May 27 2016 and Depth - June 10 2016) Watch

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    (Original post by ineedA)
    Didn't realise the question said non linear , oops how many makrs was that
    4 marks in total. 1 for the angle and 3 for the explanation I'm guessing.
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    (Original post by TH3-FL45H)
    4 marks in total. 1 for the angle and 3 for the explanation I'm guessing.
    I put all electron pairs repel, lone pairs repel more, but I spoke about linear, 180 degrees , how many marks do you think I lost? 4 or 3
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    (Original post by ActuallyIDo)
    couldn't even spell Markovnikov and forgot to put H2O at the end of the oxidation question.....

    **** me too...
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    Unofficial mark scheme?
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    (Original post by ineedA)
    I put all electron pairs repel, lone pairs repel more, but I spoke about linear, 180 degrees , how many marks do you think I lost? 4 or 3
    2 or 3 I think
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    (Original post by 4nonymous)
    Unofficial mark scheme?
    http://www.thestudentroom.co.uk/show....php?t=4156327

    also https://twitter.com/chemistryalevel might put one up. He did for the breadth paper
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    Also spelt Markovnikov wrong ffs. I doubt I lost any marks though because I wrote what the rule is and why it works (tertiary carbocations being more stable etc)
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    I made the silly mistake of putting butanoic acid however I made my working out clear and i only failed at the mass spec and therefore I can imagine I lost 2 marks. If you guys showed your working properly and came to the wrong conclusion I wouldn't worry about it too much.

    Apart form that it was a nice paper.
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    On the last question i messed up the formula and got propanoic acid. However i stated that the m/z is 88 and stated that there is an o-h bond and c = o bond. I stated that its a carboxyllic and and what the peaks 73 and 43 on the mass spec referred to. How many marks do you reckon ill get? Im thinking 2 max and possibly 0
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    (Original post by Ajan123)
    What points did you write for the bond angle question and the explanation: I was suprised that it was 4 marks. This is what i wrote:
    1) 104.5
    2) Electron pairs repel as far as possible.
    3) Lone pairs repel more than bonded pairs decreasing bond angle by 2.5 per lone pair?
    I would say thats 3/4, as it was 4 marks i think you might have had to state that there were 2 lone pairs and 2 bonded pairs as oxygen has 6 outer electrons so has 4 left after bonding so 2 lone pairs.
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    Rgding the last question:

    There is no such thing as 2-methylpropanoic acid. The compound is methylpropanoic acid.
    If the stem is 'prop', any alkyl groups must be attached to the second carbon atom- otherwise the stem changes to 'but'.
    The '2' is therefore redundant.

    (Not sure if marks will be docked for this.)
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    Since both papers were decent, my prediction for grade boundaries:

    A - 112
    B - 98
    C - 84
    D - 70
    E - 56
    U - 0-55
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    (Original post by alphadelta)
    Rgding the last question:

    There is no such thing as 2-methylpropanoic acid. The compound is methylpropanoic acid.
    If the stem is 'prop', any alkyl groups must be attached to the second carbon atom- otherwise the stem changes to 'but'.
    The '2' is therefore redundant.

    (Not sure if marks will be docked for this.)
    It doesnt matter they mean the same thing
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    (Original post by TH3-FL45H)
    also https://twitter.com/chemistryalevel might put one up. He did for the breadth paper
    He has been told by OCR to stop posting his answers to the 2016 papers.
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    Isn't that a bit high considering no UMS?
    (Original post by oni176)
    Since both papers were decent, my prediction for grade boundaries:

    A - 112
    B - 98
    C - 84
    D - 70
    E - 56
    U - 0-55
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    (Original post by asinghj)
    From what I can remember:
    electronic configuration of magnesium 1s2 2s2 2p6 3s2
    Metal Calcium
    What happens to volume of H2 when a metal from further down is used? Lower volume as less number of moles of metal
    P4 and Cl2? P4 has more electrons so stronger London forces and stuff
    Mg and Si? Mg is metallic and Si was covalent
    Pressure? 4.something *10^6 Pa
    First 6 marker? The electrophilic substitution and the tertiary carbonation is more stable so that product is made more
    Percentage yield? 65.4 (or 64.5) %
    Second 6 marker? It had to be 2-methylpropanoic acid. The peak at 43 wouldn't work if it was butanoic acid.


    Overall an easy paper..


    Just a quick question. If I crossed out my answer from answer space and wrote the answer in additional space would that be marked the same?
    Because I redrew the enthalpy profile diagram on the back
    The peak did work for butanoic acid actually. Just gunna assume I got it wrong anyway

    Posted from TSR Mobile
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    (Original post by Alishajani10)
    Isn't that a bit high considering no UMS?
    I am not sure whether UMS will be provided, but everyone is saying how easy both papers were. So I think they will keep the boundaries as same as 80% for an A, 70% for a B etc.
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    for the pv=nrt question, how did you calculate n?
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    (Original post by oni176)
    I am not sure whether UMS will be provided, but everyone is saying how easy both papers were. So I think they will keep the boundaries as same as 80% for an A, 70% for a B etc.
    I think I got exactly 112. Was thinking it'd be around 106 for an A - it's a new spec, all the content assessed in both papers too
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    (Original post by jhoelvvq)
    for the pv=nrt question, how did you calculate n?
    Mass given in question/molar mass of the compound
 
 
 
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