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

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    (Original post by ashly.alava)
    ln16.9
    but why though the question said
    lnA = 16.9

    Thinking about it,
    ln k = ln A – Ea/RT
    Ea= lnA-lnK/RT
    =16.9 - lnk /(8.31x298) where k is the rate constant which you found before.
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    (Original post by ashly.alava)
    LiALH4 if correct also you could add Pt/Ni catalyst that was probably the condition ?
    I thought the question was asking what the 2 intermediates were and then you write the conditions to get those intermediates and not the final product...
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    what did u speak about in separating the R and S isomer using C13 NMR
    was difficult
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    (Original post by Miss.Modesty)
    I thought the question was asking what the 2 intermediates were and then you write the conditions to get those intermediates and not the final product...
    Question was asking for 2 intermediates and the reagents and conditions for the 3 stages
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    (Original post by tangled23)
    did you get n ethylpropanamide for the name
    yeah
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    (Original post by ashly.alava)
    LiALH4 if correct also you could add Pt/Ni catalyst that was probably the condition ?
    ahh i ran out of time so i just put catalyst and the equation do you think its possible to get a mark for just saying LiAlH4
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    (Original post by GangRelated)
    but why though the question said
    lnA = 16.9

    Thinking about it,
    ln k = ln A – Ea/RT
    Ea= lnA-lnK/RT
    =16.9 - lnk /(8.31x298) where k is the rate constant which you found before.
    oml maybe you are right tbh I do not remember but I though the question said A=16.9 but maybe it said lnA **** it was so hot I couldn't even think
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    (Original post by Emz99)
    I got Ea as 15 something as well on the specimen paper i got it wrong because i put it all in the calc at once and for some reason log laws I think it didnt work out. When i did ln k and ln a seperately and then substituted I got it right. I did the same in the exam and got 15 something im pretty I am right on this. Also fam for the mg all you had to do was pv =nrt work out moles times by mr x10? not sure about that one.
    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
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    (Original post by tangled23)
    did you get n ethylpropanamide for the name
    N-ethylPropanamide is the correct IUPAC term.
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    (Original post by redwolf6504)
    i got 1100mg ....... yh ill just leave
    I got about 50000 mg I don't understand how we were supposed to do it without a temperature
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    (Original post by GangRelated)
    N-ethylPropanamide is the correct IUPAC term.
    Loool the hyphen ain't that deep fam
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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
    no offence but do you always type like that...
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    Cant remember which way round R and S were but i put something along the lines of one only had one peak in the range 20-50ppm for carbons adjacent to c=o as only ch2 was attached in when the carbonyls were both in the middle then for the other there'd be 2 peaks for C=O as there was a methyl group and ch2 attached to each carbonyl.
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    (Original post by Jessie1999)
    Yeah I got 870mg as well.
    Same ☺️😅


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    (Original post by student1099)
    no offence but do you always type like that...
    Because I'm not a Cambridge student
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    (Original post by GangRelated)
    N-ethylPropanamide is the correct IUPAC term.
    agreed
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    (Original post by poppyb787)
    I got about 50000 mg I don't understand how we were supposed to do it without a temperature
    the temp was given 25C and you had to convert into kelvin
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    (Original post by redwolf6504)
    the temp was given 25C and you had to convert into kelvin
    hahahahahahahahaha i stared at this for ages and was trying to do all sorts of weird things and i've screwed it because I can't read the questions that is excellent
    thanks haha
    i swear it just said 'burnt in air and then cooled to same temperature' or something like that
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    (Original post by poppyb787)
    hahahahahahahahaha i stared at this for ages and was trying to do all sorts of weird things and i've screwed it because I can't read the questions that is excellent
    thanks haha
    i swear it just said 'burnt in air and then cooled to same temperature' or something like that
    nah it defo said 25C
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    Right now im just like

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