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AQA CHEM4 - 13th June 2012

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    (Original post by Bright.Inspiration.)
    Oh my word...
    I don't think the exam ever has organic synthesis questions with as many steps as that, and as thegodofgod pointed out, there is a much easier way to do that one.

    I think it helps to remember common patterns, such as nucleophilic addition/substitution with C\equivN- if carbon chain increases by 1 etc.
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    (Original post by Glacier)
    I don't think the exam ever has organic synthesis questions with as many steps as that, and as thegodofgod pointed out, there is a much easier way to do that one.

    I think it helps to remember common patterns, such as nucleophilic addition/substitution with C\equivN- if carbon chain increases by 1 etc.
    Think i would be so screwed if that came up lol.

    Really dont like it, doesn't help that no textbook has any questions on it either...
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    (Original post by Doctor.)
    Think i would be so screwed if that came up lol.

    Really dont like it, doesn't help that no textbook has any questions on it either...
    Does your school have a subscription to Kerboodle online resources by Nelson Thornes? They have quite a few practice questions on synthetic routes.
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    (Original post by Glacier)
    Does your school have a subscription to Kerboodle online resources by Nelson Thornes? They have quite a few practice questions on synthetic routes.
    I don't go to a school. so no access to that
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    (Original post by Doctor.)
    I don't go to a school. so no access to that
    Oh, are you on a gap year then? I'll post the questions here if you want to have a go:
    • propan-1-ol \rightarrow 2-bromopropane
    • benzene \rightarrow phenylamine
    • ethane \rightarrow ethylamine
    • phenylmethanol \rightarrow methylbenzoate
    • bromomethane \rightarrow ethylamine
    • phenylamine \rightarrow N-(4-nitrophenyl)ethanamide
    • propene \rightarrow propanone
    • ethanol \rightarrow ethane-1,2-diol
    Let me know if you want to check any of the answers.
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    (Original post by Glacier)
    Oh, are you on a gap year then? I'll post the questions here if you want to have a go:
    • propan-1-ol \rightarrow 2-bromopropane
    • benzene \rightarrow phenylamine
    • ethane \rightarrow ethylamine
    • phenylmethanol \rightarrow methylbenzoate
    • bromomethane \rightarrow ethylamine
    • phenylamine \rightarrow N-(4-nitrophenyl)ethanamide
    • propene \rightarrow propanone
    • ethanol \rightarrow ethane-1,2-diol
    Let me know if you want to check any of the answers.
    Quick question, do you have to heat/reflux a secondary alcohol if you want to oxidise it to a ketone, or do you just have to heat it?
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    (Original post by thegodofgod)
    Quick question, do you have to heat/reflux a secondary alcohol if you want to oxidise it to a ketone, or do you just have to heat it?
    Kerboodle says that it should be refluxed, but I'm not sure if it's necessary since there's only 1 possible product. I'll have a look at some past papers later to see if there are any questions about this.
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    (Original post by Glacier)
    Oh, are you on a gap year then? I'll post the questions here if you want to have a go:
    • propan-1-ol \rightarrow 2-bromopropane
    • benzene \rightarrow phenylamine
    • ethane \rightarrow ethylamine
    • phenylmethanol \rightarrow methylbenzoate
    • bromomethane \rightarrow ethylamine
    • phenylamine \rightarrow N-(4-nitrophenyl)ethanamide
    • propene \rightarrow propanone
    • ethanol \rightarrow ethane-1,2-diol
    Let me know if you want to check any of the answers.
    Aw that's awesome, I am going to start doing chem today so thanks so much!!!
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    Just did the January 2012 exam as a mock, didn't do the best or anything :/. Missed some easy marks
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    (Original post by Glacier)
    Oh, are you on a gap year then? I'll post the questions here if you want to have a go:
    • propan-1-ol \rightarrow 2-bromopropane
    • benzene \rightarrow phenylamine
    • ethane \rightarrow ethylamine
    • phenylmethanol \rightarrow methylbenzoate
    • bromomethane \rightarrow ethylamine
    • phenylamine \rightarrow N-(4-nitrophenyl)ethanamide
    • propene \rightarrow propanone
    • ethanol \rightarrow ethane-1,2-diol
    Let me know if you want to check any of the answers.
    Would really appreciate the answers to the ones in bold please

    Think I am doing better on CHEM4 in general now, BUT I made a mess of tge Ph calculations in the mock paper I did
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    (Original post by Doctor.)
    Would really appreciate the answers to the ones in bold please

    Think I am doing better on CHEM4 in general now, BUT I made a mess of tge Ph calculations in the mock paper I did
    • phenylmethanol \rightarrow methylbenzoate
    • oxidation to benzoic acid (benzenecarboxylic acid) with K2Cr2O7/H+ and reflux, then esterification using CH3OH with conc. H2SO4 and reflux
    • phenylamine \rightarrow N-(4-nitrophenyl)ethanamide
    • acylation (nucleophilic addition-elimination) with CH3COCl to make N-phenylamide (remember that acylation with amines makes N-substituted amides), then nitration (electrophilic substitution) with conc. H2SO4 and conc. HNO3
    • ethanol \rightarrow ethane-1,2-diol
    • dehydration to ethene with conc. H2SO4 and reflux, then electrophilic addition with Br2 to make 1,2-dibromoethane, then reflux with NaOH (nucleophilic substition) to substitute both bromine atoms for OH groups
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    (Original post by Doctor.)
    Just did the January 2012 exam as a mock, didn't do the best or anything :/. Missed some easy marks
    That exam was a bitch of a paper :mad:

    So unlike all of the previous Unit 4 papers.
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    (Original post by thegodofgod)
    That exam was a bitch of a paper :mad:

    So unlike all of the previous Unit 4 papers.
    I'll be doing that paper tomorrow. Do you know where to get the examiner's report for it?

    (Original post by thegodofgod)
    Quick question, do you have to heat/reflux a secondary alcohol if you want to oxidise it to a ketone, or do you just have to heat it?
    I had a look through some more past paper questions today and still haven't found anything about conditions for oxidising secondary alcohols.
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    (Original post by thegodofgod)
    That exam was a bitch of a paper :mad:

    So unlike all of the previous Unit 4 papers.
    So true, overall it wasn't a MEGA HARD paper but just really different from normal. What got me was these little random 1/2 markers that were based off CHEM1 and 2.

    Then I made some retarded mistakes on calculations .

    Grade boundaries were unreasonably high tbh. Maybe a few marks lower to get an A*/cap
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    (Original post by Glacier)
    • phenylmethanol \rightarrow methylbenzoate
    • oxidation to benzoic acid (benzenecarboxylic acid) with K2Cr2O7/H+ and reflux, then esterification using CH3OH with conc. H2SO4 and reflux
    • phenylamine \rightarrow N-(4-nitrophenyl)ethanamide
    • acylation (nucleophilic addition-elimination) with CH3COCl to make N-phenylamide (remember that acylation with amines makes N-substituted amides), then nitration (electrophilic substitution) with conc. H2SO4 and conc. HNO3
    • ethanol \rightarrow ethane-1,2-diol
    • dehydration to ethene with conc. H2SO4 and reflux, then electrophilic addition with Br2 to make 1,2-dibromoethane, then reflux with NaOH (nucleophilic substition) to substitute both bromine atoms for OH groups
    Thanks so much, feel silly I wasn't able to work It out now lol. The others were not too bad

    (Original post by Glacier)
    I'll be doing that paper tomorrow. Do you know where to get the examiner's report for it?



    I had a look through some more past paper questions today and still haven't found anything about conditions for oxidising secondary alcohols.
    Oxidising? Just under reflux and K2Cr2O7

    From what I have seen, the organic synthesis isn't too bad in actual recent exam papers! Conditions are pretty relaxed/they really want to know reagents!
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    (Original post by Doctor.)
    Thanks so much, feel silly I wasn't able to work It out now lol. The others were not too bad


    Oxidising? Just under reflux and K2Cr2O7

    From what I have seen, the organic synthesis isn't too bad in actual recent exam papers! Conditions are pretty relaxed/they really want to know reagents!
    Glacier and I aren't sure whether or not to reflux, as reflux is normally used when there are 2 possible products, e.g. oxidising 1o alcohols.

    Oxidising 2o alcohols only produces ketones, so we're unsure whether refluxing is needed
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    (Original post by thegodofgod)
    Glacier and I aren't sure whether or not to reflux, as reflux is normally used when there are 2 possible products, e.g. oxidising 1o alcohols.

    Oxidising 2o alcohols only produces ketones, so we're unsure whether refluxing is needed
    oh I see! Well practically it doesn't matter If you do it to a ketone as there is no further oxidation possible.

    So tbh, I would leave it out. It's not in either of the AQA endorsed textbooks from what I remember! Can't see it being on the MS either since its not really needed. They'll probably just use the list principal and mark It wrong if the marker is stupid .
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    (Original post by Doctor.)
    oh I see! Well practically it doesn't matter If you do it to a ketone as there is no further oxidation possible.

    So tbh, I would leave it out. It's not in either of the AQA endorsed textbooks from what I remember! Can't see it being on the MS either since its not really needed. They'll probably just use the list principal and mark It wrong if the marker is stupid .
    Stupid examiners. :rolleyes:

    Like examiners would ever be stupid.

    Spoiler:
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    That was sarcasm, if you didn't recognise it
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    Just did the January 2012 paper and made so many mistakes :mad:

    Spoiler in case some people haven't done it yet and want to do it as a mock:

    Spoiler:
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    • Forgot to use V in the Kc calculation and just used the moles
    • Forgot about how to make alkaline buffers
    • Got most of the nmr questions wrong
    • Wrote 2-aminobutan-1,4-dioic acid instead of 2-aminobutane-1,4-dioic acid (I have no idea how this works )
    • Got the uses of organic compounds and examples of polymers wrong
    • Didn't realise that "reduction" and "dehydration" aren't mechanisms
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    (Original post by Glacier)
    Just did the January 2012 paper and made so many mistakes :mad:

    Spoiler in case some people haven't done it yet and want to do it as a mock:

    Spoiler:
    Show

    • Forgot to use V in the Kc calculation and just used the moles
    • Forgot about how to make alkaline buffers
    • Got most of the nmr questions wrong
    • Wrote 2-aminobutan-1,4-dioic acid instead of 2-aminobutane-1,4-dioic acid (I have no idea how this works )
    • Got the uses of organic compounds and examples of polymers wrong
    • Didn't realise that "reduction" and "dehydration" aren't mechanisms
    OMG firstly that's not bad.

    Spoiler:
    Show
    Secondly, same here The bits in bold we are the same haha. I ended up guessing a little on the buffers bit, got a few marks for it but need to go over it I guess. NMR...Messed up on the last 2 bits of it . Naming is just a bit of practice I guess, was only one mark anyway . Grrr the V in Kc annoyed me greatly . PS the naming one...it's so random but to be fair I have seen it in previous exam papers an they have emphasis that you write it correctly :/...it's not like you were miles off the correct answer either


    Tbh when you actually think about it...you've not done too bad, a few mistakes which with a little more revision and you'll be on top!

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