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OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD watch

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    (Original post by tcameron)
    Do we need to know that NaBH4 is in aqueous ethanol?
    Erm, when doing reduction the solvent used is water. We can see this from the second stage of the reaction mechanism. i.e. H- ion attaches to C and breaks pi-bond in C=O which leaves you with an O- on the end of the molecule. The O- then attacks the H of an H2O molecule, forming the alcohol and OH-.
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    (Original post by Dannyboy2015)
    Erm, when doing reduction the solvent used is water. We can see this from the second stage of the reaction mechanism. i.e. H- ion attaches to C and breaks pi-bond in C=O which leaves you with an O- on the end of the molecule. The O- then attacks the H of an H2O molecule, forming the alcohol and OH-.
    Yeah that seems true but when I learnt this in class we learnt it was in ethanol solvent idk if that's involved in the reaction though just like the ethanol solvent isn't when with excess ammonia
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    Remember in making aliphatic amines:
    Halogenoalkane + NH3 (hot, in ethanol) --> Amine + HCl

    The amine FURTHER REACTS with another halogenoalkane to make the (chain)2NH if that makes sense. Hasn't come up in years
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    Don't be caught out by "reducing agent" when it's talking about making phenylamine from nitrobenzene. This is a reduction reaction and the reducing agent is Sn/HCl

    Nitrobenzene + 6[H] --> Phenylamine + 2H2O

    If there are 2 nitro groups, double the [H] and H2O etc
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    (Original post by itsConnor_)
    Don't be caught out by "reducing agent" when it's talking about making phenylamine from nitrobenzene. This is a reduction reaction and the reducing agent is Sn/HCl

    Nitrobenzene + 6[H] --> Phenylamine + 2H2O

    If there are 2 nitro groups, double the [H] and H2O etc
    Must say concentrated HCl and reflux
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    (Original post by itsConnor_)
    Don't be caught out by "reducing agent" when it's talking about making phenylamine from nitrobenzene. This is a reduction reaction and the reducing agent is Sn/HCl

    Nitrobenzene + 6[H] --> Phenylamine + 2H2O

    If there are 2 nitro groups, double the [H] and H2O etc
    A quick way to work out the nu of [H] and H2O if unsure is to look at how many O atoms has been lost from nitrobenzene, then you can say that many moles of H2O has formed. Then you add up all the H's from H2O and from the NH2 groups to work out the amount of [H] needed.
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    If we're asked to write an equation for the formation of a condensation polymer do we write 2n H2O or (2n-1)H2O? The textbook does 2n-1 but there was a question (I think it was legacy) where you had to write the equation for the formation of kevlar and it was just 2n...?
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    (Original post by Setarehp)
    How do you calculate the mr of compound G (q4 ii) JUNE 2013??
    Earlier in the question, you're given the skeletal formula for Compound G. You can then convert this into a molecular formula (C9H23O3).
    By substituting in the relative atomic masses, the Mr Value can be calculated as 179 gmol.
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    (Original post by tcameron)
    Yeah that seems true but when I learnt this in class we learnt it was in ethanol solvent idk if that's involved in the reaction though just like the ethanol solvent isn't when with excess ammonia
    It's NaBH4 dissolved in ether followed by the addition of water

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    For the crammers:

    https://goo.gl/nVvgw9
    • Welcome Squad
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    Welcome Squad
    Is anyone else just completely doubting everything they think they know/ have done over these past months?! 😩
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    Can someone explain a Pi electron please?
    I'm slowly beginning to doubt everything i know...
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    (Original post by rahim10)
    Can someone explain a Pi electron please?
    I'm slowly beginning to doubt everything i know...
    P orbitals overlap above and below plane of molecule to produce a region of electron density called a pi bond
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    (Original post by itsConnor_)
    Remember in making aliphatic amines:
    Halogenoalkane + NH3 (hot, in ethanol) --> Amine + HCl

    The amine FURTHER REACTS with another halogenoalkane to make the (chain)2NH if that makes sense. Hasn't come up in years
    U need excess nh3
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    Wish it was at 9 instead of 1
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    Thank you everyone for all the support and answers! Glad I get it now

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    (Original post by Jehaan)
    COOH is an acid which can behave like a normal acid with a carbonate ie Na2CO3 +
    HCl => NaCl + Co2 + H2O
    (Not balanced btw)
    Whereas phenol is a weak acid so it can't react if that makes sense
    Ah I see thank you!

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    (Original post by Rust Cohle)
    For the crammers:

    https://goo.gl/nVvgw9
    Thanks for that!😊
    Do you have anything similar for f325?
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    Last minute question!

    I was wondering if one could use pencil for drawing mechanisms? Where else one can use pencil for? (can it be used for tables,diagrams, graphs?
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    (Original post by KB_97)
    Wish it was at 9 instead of 1
    thought it starts at 2
 
 
 
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