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    please help!!!
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    Electrochemical cells:
    What exactly do we need to know about these ?
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    (Original post by Deyn_08)
    can ANYONE EXPLAIN BORN HABER CYCLES AND TITRATION STUFF

    BIG THANK YOU, IM HAVING A HEART ATTACK OVER THIS
    For Born harbour cycles I remember it as:
    1. Convert the reactants to gaseous atoms
    2. Then convert those to gaseous ions (You remove electrons from one atom and in the next stage you add these electrons to form the negative ion)
    3. Then combine them to form a solid ionic lattice.
    If you do a couple of past questions; it will seem easier!!
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    I'm really scared because it seems so small and i'm worried i'm not going to learn enough to get a B because they will ask something not in the book
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    Hey guys, what topics do people think will come up? I think electrochemical cells will, seeing as their appearance in january's paper was brief, and I'm thinking the autocatalysis of Mn2+ could sneak in - like the intermediate equations for how it acts as a catalyst.
    What do people think?!

    Also, what reactions/colours do we need to know for Al compounds? Thanks!
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    I really dont get how we (in reference to the spec) how you 'deduce the e.m.f of rechargeable and non rechargeable cells'????????????? :'(
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    hey people i dont get why al203 melting point decreases because its partially covalent, because doesnt this slight polarisation mean extra bonding so the bonding is stronger, thats what it says in my book, where the ionic model lattice gives an exothermic value yet experimental value shows its more exothermic which means stonger bonding beacuase of the polarisation????????
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    (Original post by ncollier4)
    I really dont get how we (in reference to the spec) how you 'deduce the e.m.f of rechargeable and non rechargeable cells'????????????? :'(
    They will give you the emf values for the cells, all you have to do is calculate the emf. You may be asked to write out full equations so try to remember the half cells for the ones stated. Anyway I remember it by, most positive half of the cell - least positive half of the cell. But this doesn't always work, so you need to keep in mind that always no matter what is emf = RHS - LHS if you know or are given the cell representation.
    Hope this helps
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    (Original post by Sheldon)
    hey guys just thought I would post a list of some TM reactions that I made
    If you find them useful I have other notes I made like that for periodicity and some other parts.
    Thats fantastic !

    Yeah what other notes have you got mate ? upload them please !!
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    does anyone have any born haber cycle practice questions by any chance? also anyone good at titration calculations and want to explain them to me?
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    (Original post by M.A.)
    yeah i know that, but I'm talking about the reverse. It is a question in my book
    Reduction with Zn/HCl (dilute) then add excess alkali eg. XS NaOH
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    Does anyone know where to get the answers for the Exam Style Questions for the Nelson Thorne book. I can only find the AS answers
    • Thread Starter
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    (Original post by soutioirsim)
    Does anyone know where to get the answers for the Exam Style Questions for the Nelson Thorne book. I can only find the AS answers
    chem_a2_ch12_nir_ans_launch.pdf

    chem_a2_ch13_nir_ans_launch.pdf

    chem_a2_ch14_nir_ans_launch.pdf

    chem_a2_ch15_nir_ans_launch.pdf

    chem_a2_ch16_nir_ans_launch.pdf

    Theres the chem5 answers... didn't bother with chem 4 as this exam isnt synoptic with it..
    Enjoy!
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    Do we need to know AS metal extraction?
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    (Original post by LimeTree.)
    chem_a2_ch12_nir_ans_launch.pdf

    chem_a2_ch13_nir_ans_launch.pdf

    chem_a2_ch14_nir_ans_launch.pdf

    chem_a2_ch15_nir_ans_launch.pdf

    chem_a2_ch16_nir_ans_launch.pdf

    Theres the chem5 answers... didn't bother with chem 4 as this exam isnt synoptic with it..
    Enjoy!
    Thanks!
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    hey does anyone know which shells are filled when ligands form dative covalent bonds with the transition metals, its obviously not the 3 shell, is it the 4 shell? and why do they always do this form metal aqueous ions?
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    (Original post by azaking)
    They will give you the emf values for the cells, all you have to do is calculate the emf. You may be asked to write out full equations so try to remember the half cells for the ones stated. Anyway I remember it by, most positive half of the cell - least positive half of the cell. But this doesn't always work, so you need to keep in mind that always no matter what is emf = RHS - LHS if you know or are given the cell representation.
    Hope this helps

    ohhhh so the emf of a rechargeable cell and a non rechargeable one is the exact same as working out normal electrochemical cells?!

    Pfft i was fair panicking over nuffinnnn! :O

    Thanks so so much you are a star
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    OH and also.....the reactions concerning the production of methanol with the C2O3 catalyst?! I cant find the information anywhere
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    Do you know what happens straight with the exam papers are they sealed up and sent directly to the moderator/ exam board or are they kept inside the school until a later date.
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    Not sure if this has been asked before but can't seem to find it! I am VERY stuck on the January 2010 paper. Question 8C. If anyone could help it would be very appreciated!!!!! I dont understand how we are meant to know all the equations? Do we just need to memorize them??
    I'll post the link if thats helpful

    Thanks in advance

    http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN10.PDF
 
 
 
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