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    Are the reaction conditions for diazotisation < 5°C, NaNO2, HCl and phenylamine?

    Then this can couple with phenylamine or phenol which is electrophillic substitution?
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    (Original post by JackWoot)
    Are the reaction conditions for diazotisation &lt; 5°C, NaNO2, HCl and phenylamine?

    Then this can couple with phenylamine or phenol which is electrophillic substitution?
    Diazotisation is with dilute HCl.

    Do you know the conditions for the coupling reraction?
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    (Original post by I'mBadAtMaths)
    Diazotisation is with dilute HCl.

    Do you know the conditions for the coupling reraction?
    Kept below 10C to prevent a phenol forming. Also, the reagents have to be created in situ as they are very volatile and would otherwise bugger off and now work.

    Also, when you couple the diazonium salt with the phenol, has to be done over iceee.
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    (Original post by ABCDemily)
    Kept below 10C to prevent a phenol forming. Also, the reagents have to be created in situ as they are very volatile and would otherwise bugger off and now work.

    Also, when you couple the diazonium salt with the phenol, has to be done over iceee.
    Is it not also < 5C? I remember that being in a mark scheme. Also it said alkaline conditions. However I can't find that in the revision book.
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    (Original post by pav)
    won't a good colourfast dye be the one that forms covalent bonds? ( since that is the strongest bond )
    yep they're fibre reactive dyes which are the most permanent type of dye as they form strong covalent bonds.. the one i said before also has a strong colourfast bt yea the covalent bond one will be stronger so an even better colourfast than that
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    when arenes undergo electrophilic substitution for example the nitronium ions, the process in the cgp book is explained in three simple steps:
    -nitronium ion attacks benzene
    -an unstable intermediate is formed
    -H+ ion is lost

    how can I elaborate on that to get a better answer that if needed to can get me more marks? cz thats abit too simple to write the exam right?
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    (Original post by pearlover)
    when arenes undergo electrophilic substitution for example the nitronium ions, the process in the cgp book is explained in three simple steps:
    -nitronium ion attacks benzene
    -an unstable intermediate is formed
    -H+ ion is lost

    how can I elaborate on that to get a better answer that if needed to can get me more marks? cz thats abit too simple to write the exam right?
    nitronium ion attacks electron rich benzene, and the H+ ion is lost in order to regain the delocalised system and restore it's original stability.
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    can anyone exaplian why CH2(COOH)-C(OH)(COOH)-CH2(COOH) has proton environments in the ration 1:4:3. is there a symmetry here?

    Also, if the question says that 15g of ethanol produced 10.6 of pure ethanal. what is the percentage yield of ethanal? why is the answer 73.9%??
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    (Original post by pav)
    can anyone exaplian why CH2(COOH)-C(OH)(COOH)-CH2(COOH) has proton environments in the ration 1:4:3. is there a symmetry here?

    Also, if the question says that 15g of ethanol produced 10.6g of pure ethanal. what is the percentage yield of ethanal? why is the answer 73.9%??
    Well I can answer the second Q, CH3CH2OH ----> CH3CHO + H2

    So 1 mole of ethanol makes 1 mole of ethanal because of the stoichiometry.

    moles of ethanol = 15/46 = 0.326

    0.326 * 44 (Mr of ethanal) = 14.344g

    10.6/14.344 * 100 = 73.9%

    Hope that makes sense
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    (Original post by pav)
    can anyone exaplian why CH2(COOH)-C(OH)(COOH)-CH2(COOH) has proton environments in the ration 1:4:3. is there a symmetry here?

    Also, if the question says that 15g of ethanol produced 10.6 of pure ethanal. what is the percentage yield of ethanal? why is the answer 73.9%??
    For the percentage yield question the mr of ehanol is 46 and the mr of ethanal is 44. The question says that 15g of ETHANOL produced 10.6g of ETHANAL. so you divide the mr of ethanal by that of ethanol and times by 15. So:

    44/46*15=14.34782609g this is the maximum amount of ethanal that can be produced from 15g of ethanol. So you then do 10.6/14.34782609*100=73.9% to 1dp.
    Hope it helps.
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    (Original post by pav)
    can anyone exaplian why CH2(COOH)-C(OH)(COOH)-CH2(COOH) has proton environments in the ration 1:4:3. is there a symmetry here?

    Also, if the question says that 15g of ethanol produced 10.6 of pure ethanal. what is the percentage yield of ethanal? why is the answer 73.9%??
    For the nmr one, I would have thought there are 4 different proton environments in the ratio 1:4:2:1
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    Do we need to know about calculating solubilities, I know Kow isn't in the specification, are the solubility questions related to that so they are also no longer included?
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    (Original post by MyJunkIsYou)
    Do we need to know about calculating solubilities, I know Kow isn't in the specification, are the solubility questions related to that so they are also no longer included?
    No we dont need to know about calculating solubilities. Its not in the spec anymore.
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    Right at the beginning of AI in the revision book (the salters one not the cgp one) it says
    'you need to be aware of risks/benefits of a given chemical process in terms of hazards associated with raw materials, reactants, prodcuts and by-products, explosions, acidic gases, flammable gases and toxic emissions (where appropriate).'
    I don't think this has come up much before has it? I've done most of the past papers now and still dont really know what this is referring to in the exam :/
    however i just got a motivation email from my teacher which made me smile simply said:
    Becky
    Keep up the good work
    Alister
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    (Original post by beckyxo)
    Right at the beginning of AI in the revision book (the salters one not the cgp one) it says
    'you need to be aware of risks/benefits of a given chemical process in terms of hazards associated with raw materials, reactants, prodcuts and by-products, explosions, acidic gases, flammable gases and toxic emissions (where appropriate).'
    I don't think this has come up much before has it? I've done most of the past papers now and still dont really know what this is referring to in the exam :/
    however i just got a motivation email from my teacher which made me smile simply said:
    Becky
    Keep up the good work
    Alister
    Well I remember one question being "What is a safety hazard about this reaction". It produced nitric acid but you had to say it was 'corrosive/toxic' to get a mark.
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    (Original post by JackWoot)
    Well I remember one question being "What is a safety hazard about this reaction". It produced nitric acid but you had to say it was 'corrosive/toxic' to get a mark.
    oh, well thats easier than I thought haha
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    (Original post by JackWoot)
    Well I can answer the second Q, CH3CH2OH ----> CH3CHO + H2

    So 1 mole of ethanol makes 1 mole of ethanal because of the stoichiometry.

    moles of ethanol = 15/46 = 0.326

    0.326 * 44 (Mr of ethanal) = 14.344g

    10.6/14.344 * 100 = 73.9%

    Hope that makes sense

    your brilliant!..Thanks a lot
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    (Original post by zahre)
    For the nmr one, I would have thought there are 4 different proton environments in the ratio 1:4:2:1

    that's what i thought too but apprently it's not. this question is from chemical ideas so im hoping it's a lot harder then what we would get in the exam, but there is no guarantee
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    ...who else is dreading this exam?
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    (Original post by Boo!xx)
    ...who else is dreading this exam?
    me!
 
 
 
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