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AQA A-level Chemistry paper 2 7405/2 Unofficial Markscheme Watch

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    (Original post by Khanman123)
    Jeeez, I messed up that last question man. 145mg for that other one. I got 15.8 or suttin like that for Ea.

    Same man i got 15.9
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    lol i got everything wrong so y'all have done better than some ppl :P
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    (Original post by Lolexamswhat)
    Same! But I think it's bc they gave us lnA and not A or something
    It's shouldn't be tooo many marks


    No they didnt they gave us what A is equal to not ln a
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    (Original post by emilyvrl)
    Step 1 :
    H2SO4 + HNO3 --> H2NO3 + HSO4

    Step 2 :
    Methylbenzene + HNO3 --> methylnitrobenzene + H2O ( conc H2SO4 catalyst )

    Step 3 :
    MethylNitrobenzene + 6[H] --> methylphenylamime + 2H2O ( Sn/HCl catalysts , room température )

    Okay so that's all I did for the very last question . It makes sense to me but I have no clue if it's right . Any opinions ?
    i dont think so as it wanted phenylethane amine so i used free radical substitution of chlorine then added a nitrile group then H2
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    (Original post by brumtown0121)
    Yo listen g, the trick was they told u lnA was 16.3 or suttin, so u didn't have to do that, u prolly did ln16.3, which caused u to get ur answer of 15, minor u won't lose many marks as you'd get error carried forward marks
    fam you is smart. What unis did you apply too?
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    (Original post by brumtown0121)
    Was I the only one who talked about distinguishing K L M N separately???? I gave each letter its own test, cos I swear question said they were in separate test tubes and to my knowledge it wasn't a mixture, it was just separate solutions of each letter, one of u clever clogs lemme know what's up
    Nah I did that
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    (Original post by brumtown0121)
    Was I the only one who talked about distinguishing K L M N separately???? I gave each letter its own test, cos I swear question said they were in separate test tubes and to my knowledge it wasn't a mixture, it was just separate solutions of each letter, one of u clever clogs lemme know what's up
    I did that too. I said K was an optical isomer as it has a chiral carbon, would I still get the mark?
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    https://www.thestudentroom.co.uk/sho....php?t=4791640

    What did you all think of the first 2 exams? Answer the poll and see how others did to.
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    (Original post by Sapereaude45)
    Most of my classmates,me included, got around 130mg give or take depending on rounding.
    Here was my method:
    Work out volume of gas lost as CO2 by subtracting intial volume from final volume

    Use ideal gas equation to determine moles of CO2 present in gas.

    Use the fact that the combustion took place in a 6:1 ratio(Can't remember exactly)

    Multiple by Mr of the orginal compound.I also carried all sig figs unitl the end
    Also would I be marked down for naming it as N-ethylpropanamide as opposed to ethylpropanamide?I know it is techically the exact same thing but as we know AQA pedantry knows no bounds.
    Any help peeps?
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    (Original post by Khanman123)
    I got EGF for the benzene ring bit
    Me too
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    They removed coursewrok so doubt it'd be 80% for A*, more like 75%
    (Original post by Khanman123)
    Grade boundaries?? I think they'll be similar to the old spec, 75% for an A 80% for A*
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    (Original post by p____)
    I put LiAlH4 on the last question is that right or was it meant to be HCl?
    LiAlH4 is right for reduction of the nitrile compound
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    Did anyone else notice mistakes in the paper?
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    equilibrium question what did everyone get
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    A last year for AS was 60%. Paper 1 was pretty difficult too, although paper 2 was decent. I think considering this and the fact that we're doing a new specification, A will be around the 65-70% for paper 1 and around 70-75% for paper 2. I'd expect A* to be about 10% above this.
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    (Original post by RinneTensigan)
    No they didnt they gave us what A is equal to not ln a
    It was lnA as I remember.I re-read this part multiple times as I was lose marks to those silly mistakes...Hoping I didn't make too many on this paper-need an A/A*.
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    i believe this was the question for the mg of p.
    C6H10O2 +15/2O2 -> 6CO2 +5H2O
    N=PV/RT
    P=105000 pa
    V= 335 x10^-6 m^3 (total volume of gas products)
    = 155 x10^-6 m^3 (total volume after CO2 was reacted off)
    R =8.31
    T= 25+273 =298k
    How much C6H10O2 in mg was used?
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    What did everyone get for that cyclic compund question using the data sheet?
    One of my friends and I both got something like a cyclic ester-I can't remember exactly.
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    Did anyone notice the mistakes in the paper?
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    (Original post by Balthznar)
    i believe this was the question for the mg of p.
    C6H10O2 +17/2O2 -> 6CO2 +5H2O
    N=PV/RT
    P=105000 pa
    V= 335 x10^-6 m^3 (total volume of gas products)
    = 155 x10^-6 m^3 (total volume after CO2 was reacted off)
    R =8.31
    T= 25+273 =298k
    How much C6H10O2 in mg was used?
    Yeah, looks good to me.I still don't understand how people got 145mg.I think they may have forgot to subtract the two volumes of gas to find CO2, unless it was a silly error on my part!
 
 
 
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