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Edexcel A2 Chemistry Exams -6CH04 (14th June) and 6CH05 (22nd June) Discussion Thread Watch

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    (Original post by luisgr8)
    What was the last MC question?
    hexane high conc of I2 upper layer
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    If the average boundary for an A is around 69, what will it likely be this time? Lower or higher?
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    (Original post by ilovecake123)
    we were meant to apply what we know to this situation plus they gave more than enough information- it would be a completely different scenario if they told us nothing- then they would do something about it?
    Yeah, I agree. It was a tough question, but when you have people who have done all the past papers you have to put in something that's not been done before.

    (Original post by luisgr8)
    What was the last MC question?
    Hexane, water and iodine density question. (hexane + high iodine conc at top, water at the bottom).
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    (Original post by scrlk)
    Yeah, I agree. It was a tough question, but when you have people who have done all the past papers you have to put in something that's not been done before.



    Hexane, water and iodine density question. (hexane + high iodine conc at top, water at the bottom).
    Was that one option A?
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    Can someone just post the full mark scheme please
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    (Original post by luisgr8)
    That was option A right?
    Yeah.
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    Mark scheme guys, full mark scheme
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    (Original post by Ladman57)
    differences between D and the acid???
    I said there would be misty white fumes of HCl with D but not with the acid. How many marks was it ?😩😩


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    (Original post by C0balt)
    As long as you quoted values and binds you're okay I think
    And I used the C-Cl and O-h but realised now that it was phenol so I lost a mark


    I can't remember but it was quite small like +47 or something
    I said no new precipitate would form on addition of excess acid
    I said eq'm form for acid, carboxylic acid forms for acid but carboxylate for alkaline, alkaline higher yield and acid is slower

    I didn't realise there was phenol so I lost a mark there

    If you add a lot of phenol time taken would be too long and so during that time the conc of reactants would've changed significantly therefore the rate at the time of colour change would be significantly different from initial rate
    I don't think you loose a mark, because O-H IR absorption a for carboxylic acid and phenol are different
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    (Original post by sayshay)
    I said there would be misty white fumes of HCl with D but not with the acid. How many marks was it ?😩😩


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    One would be reversible and would require a catalyst. Whereas the other doesn't need a catalyst and is non reversible. It was 2 marks I think
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    The hazardous substance was Ba(OH)2 because it is a caustic Base
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    Past and average gb
    Name:  Screen Shot 2016-06-14 at 18.02.59.png
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    Not too pretty but there we go
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    (Original post by kosmoooskosmooos)
    I don't think you loose a mark, because O-H IR absorption a for carboxylic acid and phenol are different
    Do they not overlap though

    (Original post by Ssttll)
    The hazardous substance was Ba(OH)2 because it is a caustic Base
    It was either Ba(OH)2 being toxic or ammonia being toxic at high conc i think
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    (Original post by C0balt)
    Do they not overlap though



    It was either Ba(OH)2 being toxic or ammonia being toxic at high conc i think
    I put the same, I think as long as you put O-H in carboxylic acids and gave a value you should be alright? They don't full overlap, phenol is 3750-3200, carboxylic acid is 3300-2500
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    (Original post by Whizbox)
    I put the same, I think as long as you put O-H in carboxylic acids and gave a value you should be alright? They don't full overlap, phenol is 3750-3200, carboxylic acid is 3300-2500
    fingers crossed
    i didn't say it was O-H of carboxylic though and totally forgot it was a phenol
    I just said o-H absorption at 3300-2500 is absent in D and present in the acid
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    (Original post by C0balt)
    Do they not overlap though



    It was either Ba(OH)2 being toxic or ammonia being toxic at high conc i think

    Awww damn. I had written toxic then changed it to corrosive right at the end lol.
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    (Original post by C0balt)
    Do they not overlap though



    It was either Ba(OH)2 being toxic or ammonia being toxic at high conc i think
    I remember that O-H in IR do overlap. On chem guide, for lactic acid (hydroxyl + OH from carboxylic acid) results in a very broad peak
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    I think I got the titration curve question right. What if the mark scheme for this paper says DO NOT MARK for that question because people are calling in saying it was against the spec? I may have lost 6 marks because people are protesting about a question they couldn't do, but edexcel gave you enough information to do it??? What do you think they'll do?
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    (Original post by MacroniCheese)
    Awww damn. I had written toxic then changed it to corrosive right at the end lol.
    Barium hydroxide is corrosive.
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    (Original post by corpeal)
    I remember that O-H in IR do overlap. On chem guide, for lactic acid (hydroxyl + OH from carboxylic acid) results in a very broad peak
    Yes they'll produce a broad peak, but the carboxylic acid will have the peak over the values for carboxylic acid whereas the acyl chloride won't have such a broad peak
 
 
 
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