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    Right i'm going getting an early nights sleep, I think i'm ready for this exam. Good luck to you all! REMEMBER TO READ THE QUESTION FULLY, they love trying to trick us
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    Special properties of water?
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    (Original post by Regina15)
    For example in Sodium Chlorate (V) the 5 refers to the oxidation number of chlorine but in say copper (II ) sulfate, the 2 refers to the oxidation number of copper. So the roman numeral generally refers to the element it is after.

    Hope this helps.
    (Original post by theCreator)
    I dont think roman numerals ever represent a negative oxidation number, but definitely not for this exam. Could you give me an example of a oxidation number question and I would explain it better that way thanks
    Thanks, appreciate the replies. I'll just assume that the oxidation number can't be negative, as I've never seen a case where it has been.
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    (Original post by Freddy-Francis)
    Special properties of water?
    Ice is less dense than water
    This is due to their being a hydrogen bond lattice which keeps the water molecules apart. However, when they break, the water molecules get closer together and it becomes more dense.
    Relatively high melting and boiling point
    This is due down to there being hydrogen bonds which need more energy to break then usual.
    High surface tension
    Yet again due to the hydrogen bonds
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    (Original post by Freddy-Francis)
    Special properties of water?
    High Viscosity and Surface Tension. HIgh boiling point.

    leave you to explain why :P
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    (Original post by theCreator)
    I managed to get a copy of the biology paper on tuesday, hopefully I'll get my hands on this chemistry paper tomorrow
    Omg same! I'll try too
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    Remember Avogadros Constant definition too guys?

    Number of atoms per mole of a carbon 12 isotope
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    Do we have to know the definition of what a prinicpal quantum number is? Its not in the spec but I'm worried it might come up
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    has everyone done all the papers?
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    Molar Mass : Mass per mole of a substance. Units is gmol^-1
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    (Original post by blackstarz)
    Can someone help me out? Towards the end of the january 2012 paper it asks for the bond angle and shape of a "H-N-H" molecule that came from hydrazine and im not sure why the bond angle is 107.5 degrees and pyramidal. Thanks.


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    Wouldn't you have two lone pairs and two bonded pairs with a bond angle of 104.5.
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    Why does sulfur only have 7 full orbitals? I thought it had 8
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    (Original post by blackstarz)
    Can someone help me out? Towards the end of the january 2012 paper it asks for the bond angle and shape of a "H-N-H" molecule that came from hydrazine and im not sure why the bond angle is 107.5 degrees and pyramidal. Thanks.
    (Original post by Dahir123)
    Wouldn't you have two lone pairs and two bonded pairs with a bond angle of 104.5.
    The nitrogen was bonded to another nitrogen atom (H2N-NH2), so there were three bonded pairs and one lone pair
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    (Original post by hassanakhtaruk)
    What are ALL the uses we need to know for example magnesium hydroxide for the stomach pains and indigestion
    Milk of magnesia specifically is for indigestion.



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    Well I'm out guys...BEST OF LUCK TO EVERYONE TOMORROW AND I SHALL SEE YOU ALL ON THE OTHERSIDE TOMORROW...DONT DO WHAT I DID BY MAKING SILLY MISTAKES AND RUSHING THE PAPER...READ EVERY SINGLE WORD TWICE AND GIVE YOURSELF A LIMIT TO FINISH THE PAPER LIKE 45 MINUTES SO IT LEAVES YOU TIME TO CHECK BACK

    Have fun! Haha :P
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    (Original post by Dahir123)
    Milk of magnesia specifically is for indigestion.



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    Thank you! best of luck tomorrow
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    I've had enough of practice papers, im going to bed :P

    Night guys, see you here after the exam!
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    (Original post by supernova99)
    If you give me an example of a question you don't understand i could help?
    Write the formula of aluminium nitrate (V)
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    Good luck to everyone, as people have mentioned. Read the question carefully and think about it before you answer - and DO NOT rush, thats my main weakness! Again I hope you all end up with A's
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    hey guys

    There's a question in jan 2011 exam paper where we need to give dipoles to N-Br bond where Br is +ve and N is -ve .. I don't understand why that is .. can anyone explain?

    Thankss
 
 
 
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