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Edexcel - Chemistry Unit 2 - 4 June 2013 Watch

  • View Poll Results: Which topic(s) are you finding most difficult?
    Shapes of molecules and ions
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    Intermediate bonding and bond polarity
    15.95%
    Intermolecular forces
    9.82%
    Redox
    17.79%
    Group 2 & 7
    40.49%
    Kinetics & Equilibria
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    39.26%
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    Green Chemistry
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    (Original post by posthumus)
    It converts emissions into something else (usually into something less harmful).

    For example, in jet engines a catalytic converter may contain carbon monoxide, CO to react with NO (since these reduce ozone):

    2NO + 2CO ----> H2 + 2CO2
    Thank you
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    (Original post by sylly)
    Ok thanks, so it's unlikely for the paper to ask about condensation reactions?
    It may do, but they are easy to identify, is a molecule of water or some other substance lost during the reaction? If so, it's likely to be a condensation reaction.
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    It's officially over between me and George !

    I found my Edexcel endorsed AS text book (pretty damn ancient) - has way less information for unit 2 & 7. George is just stressing me out too much.... must get onto past papers quick !
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    the startch starts off as a yellow colour then turns blue-black for a short while and the end point is colourless (the iodine has been liberated)....... i think
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    (Original post by posthumus)
    It converts emissions into something else (usually into something less harmful).

    For example, in jet engines a catalytic converter may contain carbon monoxide, CO to react with NO (since these reduce ozone):

    2NO + 2CO ----> H2 + 2CO2
    You mean nitrogen instead of hydrogen for the reaction?
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    The June 2010 paper is soo much easier than the 2011 paper and the 2012 paper was easier than 2011 also. I hope that this isn't a new trend, easy->hard->easy, if so then this year it will be hard D:
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    Hopefully Section C will be on CFCs'/HCFCs' on Tuesday as it has been a while since it was a main topic
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    (Original post by James A)
    You mean nitrogen instead of hydrogen for the reaction?
    Woop My bad, thanks for pointing it out Hopefully Jay here spotted that mistake

    (Original post by Jayqwe)
    Thank you
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    I prefer it on a equillibrium reaction the questions are a lot more standard

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    how many marks do you usually have to get for full ums?
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    It really depends on what the grade boundries are! The lower the boundry for an A the lower the raw mark needed to get full ums

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    (Original post by Camellama)
    how many marks do you usually have to get for full ums?
    You should be aiming to get at least 65/80 in my opinion, if you are going for an A

    EDIT: misread your question Like goods states, at least 75/80

    (Original post by Sciencefella)
    I prefer it on a equillibrium reaction the questions are a lot more standard

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    I really doubt it, but if the whole of section C is on equilibria - I will be one happy dude. Even if it's Kinetic + Equilibria... I would love that ! But I believe there's always a bit of green chemistry in section C ¬_¬
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    (Original post by Sciencefella)
    the startch starts off as a yellow colour then turns blue-black for a short while and the end point is colourless (the iodine has been liberated)....... i think
    You add the starch when the solution is pale-yellow/straw-yellow, after adding it will form a blue-black solution and at the end point the solution should go colourless. All right.
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    (Original post by Camellama)
    how many marks do you usually have to get for full ums?
    75+ will give full or near full ums post years


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    (Original post by HarryMWilliams)
    You add the starch when the solution is pale-yellow/straw-yellow, after adding it will form a blue-black solution and at the end point the solution should go colourless. All right.
    Am I right that the reason you don't add it too early is that it allows a complex to form that is insoluble and so if added to early the colour change doesn't occur at the true end point and you overshoot?


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    (Original post by Camellama)
    how many marks do you usually have to get for full ums?
    Well unfortunately they have been rising quite substantially, for example the Jan 2013 paper=77/80, may 2012=75/80,may 2011=70/80,may 2010=72/80

    so I reckon for Tuesday it will be 79/80 for full ums lool
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    Do u need to be able to draw shapes of molecules by showing which parts stick out the page and which parts go into the page


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    (Original post by Goods)
    x
    Yeah, if you add the starch to early it forms an insoluble iodine-starch complex which you dont want.

    (Original post by Sciencefella)
    x
    No, thats talking about the different planes, it's not necessary at AS I believe.
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    (Original post by Sciencefella)
    Do u need to be able to draw shapes of molecules by showing which parts stick out the page and which parts go into the page


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    Yep, you need to be able to draw the 3D shapes.

    e.g. Ammonia
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    Do you need to know the specifics of the uses of halogenoalkanes? i.e. do you need to know the actual names like PTFE, polychloroethane, HCFC's etc?
 
 
 
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