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Edexcel - Chemistry Unit 2 - 4 June 2013 Watch

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    (Original post by GCSE-help)
    Thanks
    Hydrolysis of secondary halogenoalkane follow both SN1 and SN2 mechanisms. Both will be accepted as long you have showed it correct.

    I got Unit 4 on 12th of June. For some reason, I'm finding it easier than Unit 2. :confused:
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    (Original post by Polish master)
    For all this Sn1 ans Sn2 business surely the answer for suggest a mechanism was neucleophilic substitution and you wouldn't have to specify Sn1 or Sn2. I make this assumption because we have to bare in mind that this was a paper aimed at year 12's and the Sn1 and Sn2 is a year 13 thing. Which leads me to believe that a fair few of you are in my position which is people who are resitting and are in year 13, hence you mentioning Sn1 and Sn2 which may have been over complicating the question. Also us year 13's dont even know how to decide weather a secondary will undergo Sn1 or Sn2 so I doubt they would expect a year 12 to know. I'm not saying I'm right but that's just my thought on the matter.
    Year 12's are expected to know the Sn1 and Sn2 mechanisms, and be able to draw them fully. And the Facer book does tell you which undergo which, and which prefer which. There is a graph with different speeds etc in the book.
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    (Original post by beaver_tron)
    Year 12's are expected to know the Sn1 and Sn2 mechanisms, and be able to draw them fully. And the Facer book does tell you which undergo which, and which prefer which. There is a graph with different speeds etc in the book.
    I have read the spec and I cant see it that for unit 2 that they are expected to know the Sn1 and Sn2, also the facer book goes into way too much unnecessary detail.
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    (Original post by Polish master)
    I have read the spec and I cant see it that for unit 2 that they are expected to know the Sn1 and Sn2, also the facer book goes into way too much unnecessary detail.
    If you find the spec online, page 43, 2.11 section f, "describe the mechanisms of the substitution reactions of halogenoalkanes and those in.."

    I interpret that as being, be able to both draw, and write what happens. Also, based on past papers, the question is nothing new, and has been asked in previous papers.

    You say it goes into unnecessary detail, but, clearly not, as a question came up that could've been answered if you had looked in the George Facer book.
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    guys you know for the multi choice with ethanol and silver nitrate - was the answer redox or nucleophilic substition?
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    (Original post by beaver_tron)
    If you find the spec online, page 43, 2.11 section f, "describe the mechanisms of the substitution reactions of halogenoalkanes and those in.."

    I interpret that as being, be able to both draw, and write what happens. Also, based on past papers, the question is nothing new, and has been asked in previous papers.

    You say it goes into unnecessary detail, but, clearly not, as a question came up that could've been answered if you had looked in the George Facer book.
    You MAY be right on your stance about the Sn1/2 buissness, but you are most definitely wrong about George Facer text book. It certainly DOES go into way too much unnecessary detail, but it's still a brilliant book to have
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    (Original post by GCSE-help)
    You MAY be right on your stance about the Sn1/2 buissness, but you are most definitely wrong about George Facer text book. It certainly DOES go into way too much unnecessary detail, but it's still a brilliant book to have
    I'm sure the facer book is good however I believe that it is filled with certain information that is way to advance and somewhat unnecessary information for that specific unit.
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    (Original post by Polish master)
    I'm sure the facer book is good however I believe that it is filled with certain information that is way to advance and somewhat unnecessary information for that specific unit.
    the answer was to use sn1 for the mechanism
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    (Original post by beaver_tron)
    If you find the spec online, page 43, 2.11 section f, "describe the mechanisms of the substitution reactions of halogenoalkanes and those in.."

    I interpret that as being, be able to both draw, and write what happens. Also, based on past papers, the question is nothing new, and has been asked in previous papers.

    You say it goes into unnecessary detail, but, clearly not, as a question came up that could've been answered if you had looked in the George Facer book.
    Well I interpret that as the Nucleophillic substitutions with halogenoalkanes and their mechanisms with other Nucleophiles such as water, Ammonia which are all in the spec along with a hydroxide. And it has only appeared once in regards to drawing the transition states as far as I can remember
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    (Original post by Meehar17)
    the answer was to use sn1 for the mechanism
    What about SN2
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    (Original post by Linked)
    guys you know for the multi choice with ethanol and silver nitrate - was the answer redox or nucleophilic substition?
    Hi I put redox but I was unsure between nucleophilic sub and redox
    What did u put?


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    (Original post by Polish master)
    Well I interpret that as the Nucleophillic substitutions with halogenoalkanes and their mechanisms with other Nucleophiles such as water, Ammonia which are all in the spec along with a hydroxide. And it has only appeared once in regards to drawing the transition states as far as I can remember
    Yes, so like I said, this is in the spec. And in past papers.
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    (Original post by GCSE-help)
    You MAY be right on your stance about the Sn1/2 buissness, but you are most definitely wrong about George Facer text book. It certainly DOES go into way too much unnecessary detail, but it's still a brilliant book to have
    I didn't say it was all needed, I myself skip certain bits, but, this bit is obviously needed, as a question came up on it.

    (I stack all my books on my desk and work through each section from each book, that way you learn what is on the spec / is really important, as it appears in all the books)
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    (Original post by beaver_tron)
    I didn't say it was all needed, I myself skip certain bits, but, this bit is obviously needed, as a question came up on it.

    (I stack all my books on my desk and work through each section from each book, that way you learn what is on the spec / is really important, as it appears in all the books)
    Well the Sn stands for Nuecleophilic substitution so we are both right haha and as it is a secondary it can under go 1 or 2
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    (Original post by Polish master)
    Well the Sn stands for Nuecleophilic substitution so we are both right haha and as it is a secondary it can under go 1 or 2
    Truth, and they can all undergo each one just at different speeds.
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    (Original post by James A)
    Same! I did this too!
    Me too. :cool:
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    (Original post by Polish master)
    Well the Sn stands for Nuecleophilic substitution so we are both right haha and as it is a secondary it can under go 1 or 2
    1/2 is the overall order of the rate equation. SN1 is unimolecular and SN2 is bimolecular. For 2ndary halogenoalkane, both will be accepted.

    Just drop this topic, guys. You are fine using either one of these mechanisms. :cool:
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    In the titration question do u have to times the percentage uncertainty by 2
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    (Original post by geor)
    Hey guys, do you think they will accept brown to colourless for the titration colour change question or not?
    Why is it colourless?

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    (Original post by geor)
    I think it's nucleophilic substitution


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    Oh damn


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