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Edexcel - Chemistry Unit 2 - 4 June 2013 Watch

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    (Original post by charlieejobson)
    have we covered free radical elimination? or is it just substitution?
    We do have free radical Substitution (CH3, Cl and U.V)

    free radical elimination is not in syllabus (i believe )
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    butan-1-ol dissolves in the HCl because it does h bonding. it says it protonates the butan-1-ol, but i'm not sure what that means?
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    (Original post by HarryMWilliams)
    Make sure you understand what you've written there, the first "part", where you add the NaOH (in water) to the haloalkane is just converting it to an alcohol. As a consequence you are also liberating the halide ion which you can then test with the aqueous silver nitrate solution.
    Water acts as a nucleophile anyway? Hence it will react to remove the halide anyway if you just add AgNO3 aq so adding NaOH speeds it up but isn't necessary to test what type of halide is present
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    (Original post by charlieejobson)
    butan-1-ol dissolves in the HCl because it does h bonding. it says it protonates the butan-1-ol, but i'm not sure what that means?
    Protonating is when H+ is given...

    ... and do we actually need to know this ? haven't seen this one at all... Isn't it usually halogenoalkane -----> alcohol with acid, H+ catalyst & not the other way around. Or is it reversible ?
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    not sure u read it properly, but well u do distillation u get two layer one aqous and organic

    we remove aqueous (seperating funnel can be used) and the organic layer will have 1bromoButene , Bromine and unreacted Butan-1-ol,
    to purify it just redistillate to a sharp boiling point which matches with data source of boiling point of 1bromoButene.

    hope u get the purifying part.
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    Guys, for reactivity rates when it comes to Halogenoalkanes, I know that there are two factors which have a say, the Halogen involved and the structure (primary, secondary or tertiary). But what about if these two factors are BOTH involved. For example, would a secondary iodoalkane react faster than a Tertiary Bromoalkane? Mind boggles haha
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    (Original post by geor)
    Exactly!
    Cheers. You seem to know your stuff, could you also please look at another question I posted? Thanks
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    What book are u'll referring to ?
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    (Original post by GCSE-help)
    Guys, for reactivity rates when it comes to Halogenoalkanes, I know that there are two factors which have a say, the Halogen involved and the structure (primary, secondary or tertiary). But what about if these two factors are BOTH involved. For example, would a secondary iodoalkane react faster than a Tertiary Bromoalkane? Mind boggles haha
    I don't think they would confuse candidates like that, because there is no hard and fast rule for determining which of those two compounds would react faster.
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    (Original post by GCSE-help)
    Guys, for reactivity rates when it comes to Halogenoalkanes, I know that there are two factors which have a say, the Halogen involved and the structure (primary, secondary or tertiary). But what about if these two factors are BOTH involved. For example, would a secondary iodoalkane react faster than a Tertiary Bromoalkane? Mind boggles haha
    Ha ha hope they don't give such questions,:lolwut:

    it's simple out of sylabuss i guess :nutcase:
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    (Original post by geor)
    It protonates the alcohol making it ionic and therefore more soluble in water (so it will be drained off with the aqueous layer in the separating funnel)
    CH3CH2CH2CH2OH + H+ → CH3CH2CH2CH2OH2+
    Im pretty sure butan-1-ol is soluble enough in water, so would it really need to be protonated?

    Could the HCl be added to neutralise any base, present?

    As far as I'm aware, the solubility of aliphatic alcohols decrease with an increase in chain length.
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    (Original post by geor)
    Haha thanks. I think a secondary iodoalkane and a tertiary bromoalkane would probably take very similar times to react. I'm not sure on the true answer though, however.
    There also unlikely to ask about secondary haloalkanes because they react via both SN1 and SN2 mechanisms
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    (Original post by geor)
    Well I guess the protonated alcohol would be a lot more soluble due to having a positive charge rather than a delta+. Although I do see what you mean, to be honest I haven't really seen the HCl step very often - only in a couple of textbooks. I don't think it's a necessary step.
    If the question had not mentioned the use of a base, I would be inclined to talk about the HCl protonating the alcohol, hence ionic interactions take place between the water and the alcohol. It all depends on the stem of the question.
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    I wonder what to study for section c, is there any trends for the ques that might come out in section c, I know it's all about green chemistry but there nothing much in textbook

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    Hey does anyone have the jan 13 paper and mark scheme? I'd much appreciate it
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    (Original post by posthumus)
    An understanding of different reagents such as... free radicals, nucleophiles, electrophiles??? (if it hasn't been mentioned already)

    EDIT: Oh wait I think Harry has the better answer Each functional group gives the compound unique properties. It could also be talking about primary, secondary & tertiary.... like primary undergoes sn2, while tertiary sn1
    Hi, Can you please tell me what sn1, sn2 means. Thank you,
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    (Original post by Goods)
    Questions are different to their numbers... I use my phone so it's hard unless there's an actual question. I would draw this Attachment 221925.


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    Sorry, thank you very much as I looked through every page in the text book and couldn't find a diagram involving ceramic wool
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    (Original post by xstarsx67)
    Hey does anyone have the jan 13 paper and mark scheme? I'd much appreciate it
    6CH02_01_que_20130116.pdf6CH02_01_rms_20130307.pdf
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    (Original post by xstarsx67)
    Hey does anyone have the jan 13 paper and mark scheme? I'd much appreciate it
    I don't know if the files attached successfully (I'm new to this HaHa)
    Attached Images
  1. File Type: pdf 6CH02 Jan 2013.pdf (453.6 KB, 60 views)
  2. File Type: pdf 6CH02 ms Jan 2013.pdf (226.4 KB, 56 views)
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    Does anyone have any practice papers or questions? I've done all the past papers!
 
 
 
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