8CH02 Paper 2 EDEXCEL CHEMISTRY Friday 10th June 2016

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    (Original post by seal_333)
    What was the 6 marker on? Did you have to draw any mechanisms and what were they? Many thanks to anyone who helps
    6 marker: Write how you would measure the rate of Hydrolysis for 2-chlorobutane, 2-bromobutane and 2-iodobutane and state the result of the experiment (something like that)

    We had to draw in arrows into a mechanism with water and there were 1 or 2 choice questions on mechanisms


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    (Original post by Florent venhari)
    6 marker: Write how you would measure the rate of Hydrolysis for 2-chlorobutane, 2-bromobutane and 2-iodobutane and state the result of the experiment (something like that)

    We had to draw in arrows into a mechanism with water and there were 1 or 2 choice questions on mechanisms


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    Oh that's interesting, that exact experiment was on one of the specimen papers, right?!
    Thank you so much, very helpful
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    What did people put for how to prepare the acid?? i completely guessed?
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    (Original post by maddie001)
    What did people put for how to prepare the acid?? i completely guessed?
    I wrote:
    Dissolve about 1 g of the acid in 100cm3 of distilled water. This should be done in a conical flask and one should stir the liquid until the solid has dissolved. Then one should transfer this solution to a 250cm3 volumetric flask using a burette (I meant to say pipette but it's not a big problem). Then one should make the solution up to the mark up to 250cm3 using deionised water I kinda made it up along the way too


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    My answers for the questions I can remember:

    Percentage Yield was 39.1%
    n was 2.25 so 2 to the nearest whole number.
    It was a Z isomer.
    The correct alcohol was 3-methylbutan-1-ol

    For the halogenoalkanes question, the usual heat with ethanol, allow to cool, add sliver nitrate, time how long it takes a precipitate to form. That's your first 3 marks. Then say the order (fastest to slowest) will be iodo, bromo, chloro as C-X bond gets longer/shorter so the bond strength is weaker/stronger.

    For the preparing acid question, I thought 4 marks means I have to add some detail. So I said weigh your mass of acid, add to 100cm^3 of water and dissolve it, then fill up to the 250cm^3 mark, shaking it as you go.

    Thought it was harder than Paper 1. Most of my lost marks will be on the annoying questions like 'how would n be affected' or 'suggest changes to the apparatus'. I would guess I got between 60 and 70.
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    Also, Florent venhari and clairebear101 and zak_121 I did the enthalpy diagrams like a combustion cycle- because you are marking the thing at the bottom.
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    (Original post by richpanda)
    Also, Florent venhari and clairebear101 and zak_121 I did the enthalpy diagrams like a combustion cycle- because you are marking the thing at the bottom.
    I put it as a formation cycle. The others did it as a combustion. I think it should be like a combustion cycle


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    (Original post by Florent venhari)
    I put it as a formation cycle. The others did it as a combustion. I think it should be like a combustion cycle


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    its defo a cycle of hydration, i did a question exactly like it in class before the exam. Both reactions formed the same hydrated product
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    The one regret I have about that exam.....is forgetting to write invert the volumetric flask to ensure a uniform concentration. I had prepared that point for such a question, but forgot in the exam. Still, that's 3/4.
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    (Original post by Florent venhari)
    I wrote:
    Dissolve about 1 g of the acid in 100cm3 of distilled water. This should be done in a conical flask and one should stir the liquid until the solid has dissolved. Then one should transfer this solution to a 250cm3 volumetric flask using a burette (I meant to say pipette but it's not a big problem). Then one should make the solution up to the mark up to 250cm3 using deionised water I kinda made it up along the way too


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    Don;y worry u dont need either! in class we used a funnel to transfer to the conical flask and thats what i put I didnt mention the stirring rod tho as ran out of time but i think i may have wrote enough if there is more than 4 marking points allowed
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    Yea I'd bet the marks would be as following

    first for saying weigh out and add (1g) to distilled water (in beaker)
    second for saying stir (with rod)
    third take 250 cm^3 and transfer solution and rinsings from (stirring thing and beaker)
    fourth make up to the mark and invert
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    have any of you guy got your papers?
 
 
 
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