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    (Original post by C0balt)
    Attachment 405207
    Ignore the top it was for someone else


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    You are AWESOME!
    Thankyou!
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    (Original post by alevels2k15)
    You are AWESOME!
    Thankyou!
    No problem


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    Does anyone have any predictions as to what might come up?
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    (Original post by Lilieeeeeee)
    Does anyone have any predictions as to what might come up?
    its going to be harder thats all I know
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    what do we need to learn and memorize for edexcel
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    (Original post by Signorina)
    How do you find out the relative abundance? Anyone? I kind of understand how to for percentage abundance, but not when it's not percentage!!

    The question is m/z 113 and m/z 115. the relative atomic mass is 114.5. whats the relative abundance!!!!!!
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    Yes thank you i think i get it now
    (Original post by C0balt)
    Write out the spdf notation for aluminium
    1s2 2s2 2p6 2s2 2p1
    Electron is removed from outside to inside, so third, fourth, 10th 11th and 12th and 13th are removal from s orbital

    Al2+(g)->Al3+(g)+e-


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    I've just done the edexcel January 2012 paper and i'm confused about a couple of questions in the multiple choice, would anyone be able to help me out? (it's question 13)
    The ionic radii in nm of some ions are given below
    Li+ 0.074
    Ca 2+ 0.100
    F- 0.133
    Cl- 0.180
    O2-0.140
    S2- 0.185

    Which of the following has the most exothermic lattice energy? They all have the same crystal structure
    A - LiF
    B - LiCl
    C - CaO
    D - CaS

    The answer is C but I don't understand why, is anyone able to explain?
    With the second question i'm in the same situation (its part b of this question)

    Which of the following compounds will show the greatest difference between the experimental lattice energy and that calculated from a purely ionic model?
    A -LiF
    B - Li2O
    C - CaO
    D - CaS

    The answer is D
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    (Original post by itsConnor_)
    For the second part, as the hydrazine acts as a base, this means it is a proton acceptor (definition), so the N2H4 accepts a H+ ion to form N2H5+.

    Not sure how to explain the first part, but the other ion in water is OH-, so I suppose that is what is left when the N2H4 accepts the H+? (sorry for terrible explanation)

    Ah okay thank you!! haha no worries, that makes sense!
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    Saw this on the spec about concentration: http://gyazo.com/501fcf1dd4462f3278dcc8bfdcc630b0
    What exactly do I need to know about concentrated vs. dilute?
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    does anyone know how to answer this question the relative atomic mass of boron is 10.8, in the sample boron exists as two isotopes 10B and 11B. calculate the percentage abundance of 10B in this sample of boron.....PLEASE HELP!!
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    (Original post by chantellerose)
    I've just done the edexcel January 2012 paper and i'm confused about a couple of questions in the multiple choice, would anyone be able to help me out? (it's question 13)
    The ionic radii in nm of some ions are given below
    Li+ 0.074
    Ca 2+ 0.100
    F- 0.133
    Cl- 0.180
    O2-0.140
    S2- 0.185

    Which of the following has the most exothermic lattice energy? They all have the same crystal structure
    A - LiF
    B - LiCl
    C - CaO
    D - CaS

    The answer is C but I don't understand why, is anyone able to explain?
    With the second question i'm in the same situation (its part b of this question)

    Which of the following compounds will show the greatest difference between the experimental lattice energy and that calculated from a purely ionic model?
    A -LiF
    B - Li2O
    C - CaO
    D - CaS

    The answer is D
    Lattice energy is more exoteric the more charged and smaller the ions are Ca2+ is doubly charged than Li+ and O2- is smaller than S2-

    The difference in experimental and theoretical arise from degree if covalency. The bigger the anion the more prone it is to polarisation. S2- has the biggest ionic radius




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    (Original post by C0balt)
    Lattice energy is more exoteric the more charged and smaller the ions are Ca2+ is doubly charged than Li+ and O2- is smaller than S2-

    The difference in experimental and theoretical arise from degree if covalency. The bigger the anion the more prone it is to polarisation. S2- has the biggest ionic radius




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    And ca2+ is smaller

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    (Original post by C0balt)
    Lattice energy is more exoteric the more charged and smaller the ions are Ca2+ is doubly charged than Li+ and O2- is smaller than S2-

    The difference in experimental and theoretical arise from degree if covalency. The bigger the anion the more prone it is to polarisation. S2- has the biggest ionic radius




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    Thank you for your help!
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    (Original post by HToo)
    does anyone know how to answer this question the relative atomic mass of boron is 10.8, in the sample boron exists as two isotopes 10B and 11B. calculate the percentage abundance of 10B in this sample of boron.....PLEASE HELP!!
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    (Original post by samb1234)
    And ca2+ is smaller

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    Yeah kinda got lazy lmao


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    (Original post by C0balt)
    Hahaha thank you

    You're welcome.

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    I'm confused, so the paper got leaked and now we have a harder one???
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    For the fellow edexcel chemistry troopers, what do we think is coming up to torture us with ? I'm absolutely petrified of the exam, considering I have been constantly failing this year -do we keep our heads high and hope the paper is doable? or shall I cry now and not in the exam (as I already did that in maths). The multiple choice is devils spawn and don't get me started on Hess's law, as that is clear nonsense in my brain that cannot fathom the arrows and products at all.

    Oh well.

    Good luck nonetheless !
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    (Original post by Lilieeeeeee)
    I'm confused, so the paper got leaked and now we have a harder one???
    This is the first I've heard of it..I really doubt it bc those rumours were spread for the C2 paper also.

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