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OCR Chemistry F322~ 4th June 2013~ AS Chemistry Watch

  • View Poll Results: How did you find the exam
    Hard A= 72
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    It was okay A= 76
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    Easy A= 79
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    Very Easy A=82
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    what is the best way to revise this close to the exam?
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    (Original post by needtosucceed=))
    LOL probably..I like to help
    Oh no no I was sayin...that this thread is much longer than other biology exam threads.

    It's great though that we are ALL helping each other ~ TEAM WORK!

    Hope we can smash the exam!
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    (Original post by Jimmy20002012)
    Is that like primary halogenalkanes hydrolyse faster than secondary and terisary?


    Posted from TSR Mobile
    The exact opposite,tertiary halogen alkanes hydrolyse first
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    (Original post by MsAqa12345)
    Hey can anyone please help me? Im stuck on the may 23rd 2012 paper, question 2d? I don't understand how they draw that, I get the first bit of the ester, but where does the extra CH2 come from? If anyone could answer? Would appreciate it thanks
    This is what comes up in the mark scheme http://www.ocr.org.uk/Images/135164-...urces-june.pdf
    Sorry its a bit messy!
    I can redo it if you need me to

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    I will get full marks. :cool:
    eventhough I don't know my stuff at the moment
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    Regarding hydrolysis I read something about length of c-cl being shorter and C-I so rate of hydrolysis increase down group

    Please correct
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    (Original post by Jimmy20002012)
    Is that like primary halogenalkanes hydrolyse faster than secondary and terisary?


    Posted from TSR Mobile
    Yh I just did that paper now and those things we didn't have to learn but like HSW and similiar to Alcohols.. and that tertiary gives the fastest reaction... and things like that..

    Personally, I think learn from ur mistakes from past papers... so that u can apply to the exam tomorrow when similiar things happen..

    I hav learnt so many things in terms of what they want in mark schems..

    GOOD LUCK
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    (Original post by niceguy95)
    Regarding hydrolysis I read something about length of c-cl being shorter and C-I so rate of hydrolysis increase down group

    Please correct
    Yes thats correct
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    (Original post by niceguy95)
    Regarding hydrolysis I read something about length of c-cl being shorter and C-I so rate of hydrolysis increase down group

    Please correct
    I think the length is the same.. but the bond enthalpy for the C-I is weaker hence breaks fastest giving rise to fast rate of hydrolysis than C-cl bond...
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    (Original post by niceguy95)
    Regarding hydrolysis I read something about length of c-cl being shorter and C-I so rate of hydrolysis increase down group

    Please correct
    I don't know about that buy you get full marks for saying

    Iodine hydrolises faster because the carbon-halogen bond is weaker with iodine that chlorine therefore less energy require to break it.
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    (Original post by Alotties)
    Sorry its a bit messy!
    I can redo it if you need me to

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    OMG I was just stuck on that question.. before u posted this

    FAB!!
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    (Original post by Jacksgap)
    I think the length is the same.. but the bond enthalpy for the C-I is weaker hence breaks fastest giving rise to fast rate of hydrolysis than C-cl bond...
    You are right with the "but the bond enthalpy for the C-I is weaker hence breaks fastest giving rise to fast rate of hydrolysis than C-cl bond..." but you are incorrect saying the bond length is the same, bond length increases as you go down the group.
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    (Original post by katelovesyou)
    I think just about everything will come up as useral oh dear, but Global warming in particular hasn't come up in a while
    what do you mean by global warming- the causes or...?
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    WHy do the not allow molecular formula? they always take marks off for it. i need to remember to use structural
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    (Original post by Jacksgap)
    OMG I was just stuck on that question.. before u posted this

    FAB!!
    Haha, glad to help! I hope it wasn't too messy for you to understand!
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    (Original post by Namod)
    You are right with the "but the bond enthalpy for the C-I is weaker hence breaks fastest giving rise to fast rate of hydrolysis than C-cl bond..." but you are incorrect saying the bond length is the same, bond length decreases as you go down the group.
    Oh okay thanks for correcting me!!

    Is it due to electronegativity or something please explain..

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    The exam needs to be now, i'm pooing it. I need to revise my other subjects but I just keep on panicking over this and re-revising it.
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    sorry to be asking so many questions, but for Q (2b vi) http://www.ocr.org.uk/Images/131287-...-resources.pdf
    how are we meant to know the structure which is formed? Do we have to make assumptions on how the reaction will take place using the mechanism which they give to us? Thanks...
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    (Original post by Alotties)
    Haha, glad to help! I hope it wasn't too messy for you to understand!

    Heyy do u know ethanoic acid how do u know if it's in excess.. it's not mentioned in the question.. 6 (e) Jan 2010
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    (Original post by JimmyA*)
    The exam needs to be now, i'm pooing it. I need to revise my other subjects but I just keep on panicking over this and re-revising it.
    Don't worry... good luck

    My exam tomorrow is the last one.. I am AS student.
 
 
 
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