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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
    42
    15.22%
    It was okay A= 76
    99
    35.87%
    Easy A= 79
    75
    27.17%
    Very Easy A=82
    60
    21.74%

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    Off to school !!!
    Good luck every1

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    (Original post by GeneralOJB)
    YOU'RE ALL GOING TO FAIL

    :bhangra::bhangra::bhangra::bhangra::bhangra::bhangra::bhangra::bhangra:
    youre going to hell
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    First of all you no it is an ester that is formed because you are adding and alchohol to an carboxylic acid so its esterification. In an ester a C has a double bond to an oxygen and a single bond to another oxygen so if you look at the moleculer formula try drawing it out i cnt draw it on here hope this helps.
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    (Original post by SheriB)
    Okay litterally panicking now..CAN ANYBODY CONFIRM THIS FOR ME. WHEN TOLD TO WORK OUT STANDARD ENTHALPY CHANGE OF COMBUSTION AND WE ARE GIVING THE CHANGE OF FORMATION. DO WE NEED TO SWITCH SIGNS AT THE END??
    Just look whats in the table! If it says the DeltaHF in the table then you need to work out formation = Products - Reactants.

    If it says DeltaHC then you need to do Reactants - Products
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    Is ethane-1-2-diol primary secondary or tertiary ?
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    Quick tip for anyone still revising.
    Memorise the mechanisms on pg176-177 in the book.
    (Radical substitution, electrophilic addition, and nucleophilic substitution)
    These will definitely come up, and carry a decent amount of marks.
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    How do you work out standard enthalpy change of reaction??????
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    Good luck to you all !!!!!!!!!!!!!!
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    (Original post by ApplePearOrange5297)
    How do you work out standard enthalpy change of reaction??????
    deltaH products - deltaH reactants
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    When we increase pressure why does it say particles instead of molecules
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    For the oxidation of alcohols if the mark scheme shows it as say c2h5oh would you still get the marks for writing it as ch3ch2oh even if its not in the allow section


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    why is ozone molecule like water?
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    (Original post by Farringtonn)
    For the oxidation of alcohols if the mark scheme shows it as say c2h5oh would you still get the marks for writing it as ch3ch2oh even if its not in the allow section


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    You've given the structural formula, if it says allow structural formula then you'll be fine
    If however it specifies that it wants the molecular formula make sure you only use that!
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    (Original post by theworld)
    please. please. please. what do u mean reverse the signs? For all the numbers? or just for the answer ? or ?

    For the numbers

    e.g. is enthalpy of combustion so co2 is -45,
    when calculating formation reverse sign so that is +45
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    (Original post by Ché.)
    I was absolutely livid when went through all that effort!
    LOL.
    LIVVVVVVID!



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    haha sorry, now you're ahead for unit 4
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    Does anyone have a list of uses of organic compounds and effects of greenhouse gases that wee need to know?
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    AHHHHHHHHHH good luck!!!


    xx
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    Gooooooooooooooooooooooooooooood luck peeps
    see you on the other side
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    (Original post by JimmyA*)
    deltaH products - deltaH reactants
    Isn't that for formation?
    I thought for reaction is the other way round, reactants - products?
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    Quick question! does anyone know how to do 3 d) on the may 2012 paper?
    Attached Images
  1. File Type: pdf june 2012.pdf (200.5 KB, 54 views)
 
 
 
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