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    (Original post by Noble.)
    Saying they were substitution reactions may be correct, but it's assuming the mechanism the catalyst plays. I think the main points of that question comparing the methods of making H2O2 were the following:

    - The substance used was a catalyst, as it was regenerated at the end.
    - The atom economy of the second method is 100%, compared to the 12.7% of the first method.
    - Less waste is produced (it's also toxic waste, as it stated on the previous question about the disposing of harmful barium compounds).
    - Perhaps something about the catalyst lowering activation energy.

    I'm not sure which other questions you're referring to.
    That's a very good answer, Noble. I think I read the equation wrong, and that was what threw me, and made me write the wrong answe.

    The question I'm referring about, is the question about how is Kerosene seperated from crude oil.

    And also, what did you arite about why is Ethene produced in such small amounts?
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    (Original post by Summerdays)
    That's a very good answer, Noble. I think I read the equation wrong, and that was what threw me, and made me write the wrong answe.

    The question I'm referring about, is the question about how is Kerosene seperated from crude oil.

    And also, what did you arite about why is Ethene produced in such small amounts?
    Kerosene is separated from crude oil by fractional distillation, which is the separation of compounds by their boiling point.

    Ethene is produced, in small amounts, due to two CH3 free radicals reacting at the termination stage.

    CH3 + CH3 --> C2H6
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    (Original post by Noble.)
    Kerosene is separated from crude oil by fractional distillation, which is the separation of compounds by their boiling point.

    Ethene is produced, in small amounts, due to two CH3 free radicals reacting at the termination stage.

    CH3 + CH3 --> C2H6
    Was that both in the same question?
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    (Original post by JustDan)
    Was that both in the same question?
    No, the one about kerosene was the very first question. The question referring to the formation of ethane was in the 6/7/8 mark question about radical substitution of alkanes.
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    (Original post by Noble.)
    Kerosene is separated from crude oil by fractional distillation, which is the separation of compounds by their boiling point.

    Ethene is produced, in small amounts, due to two CH3 free radicals reacting at the termination stage.

    CH3 + CH3 --> C2H6

    Yeah, I said that also for the free radical substitution. Also, for the first question, do you think it would be an acceptable answer for me to say "Kerosone is seperated from crude oil in a fractional column based on its hydrocarbon length"?
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    (Original post by Summerdays)
    Yeah, I said that also for the free radical substitution. Also, for the first question, do you think it would be an acceptable answer for me to say "Kerosone is seperated from crude oil in a fractional column based on its hydrocarbon length"?
    It's definitely correct, just not as direct as stating "fractional distillation, and boiling points". It's very dependant on how lenient they're going to be with the mark-scheme. I don't see why you shouldn't get that though.

    It's also going to depend on how they worded the question; if the question said "By which process..." they'll probably only accept 'fractional distillation'. If they've said "How is..." I don't see how they can reject 'fractional column' as an answer. Having said that, I have a feeling it did say "By which process...".
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    (Original post by Noble.)
    It's definitely correct, just not as direct as stating "fractional distillation, and boiling points". It's very dependant on how lenient they're going to be with the mark-scheme. I don't see why you shouldn't get that though.
    Yeah, that's the thing. My mind went blank and I couldn't think of a direct answer, like the one you had. It was out of 2 marks so I'm not sure If I will get two marks or not.

    If anyone has a copy of the paper, please scan it.

    What fo you guys think the grade boundaries will be?

    EDIT: I believe the question started with "How is..."
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    (Original post by Summerdays)
    Yeah, that's the thing. My mind went blank and I couldn't think of a direct answer, like the one you had. It was out of 2 marks so I'm not sure If I will get two marks or not.

    If anyone has a copy of the paper, please scan it.

    What fo you guys think the grade boundaries will be?
    It was similar to June's paper, but the questions were a bit more indirect, which'll probably result in the boundaries being lower. I can't see the paper having boundaries higher than June's paper.
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    (Original post by Noble.)
    It was similar to June's paper, but the questions were a bit more indirect, which'll probably result in the boundaries being lower. I can't see the paper having boundaries higher than June's paper.

    Was there a question about ozone depeltion by chlorine radicals bud?
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    June's paper was about 75%. This paper should be around the same, or slightly lower. You seemed to have done well. How did you find f321?
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    (Original post by JustDan)
    Was there a question about ozone depeltion by chlorine radicals bud?
    I don't recall there being one.

    There was a question asking how Ozone is maintained in the stratosphere.
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    (Original post by Noble.)
    I don't recall there being one.

    There was a question asking how Ozone is maintained in the stratosphere.
    There was definately something on the formation of ozone, and how the rate of depletion = the rate of production.

    I must have put something in there about it in there.
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    (Original post by JustDan)
    There was definitely something on the formation of ozone, and how the rate of depletion = the rate of production.
    I don't remember that :confused:
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    (Original post by Summerdays)
    I don't remember that :confused:
    Yer, o3 + uv radiation = o2 + o

    They then react together again to form o3
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    Oh yes, the question asked how ozone is maintained.
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    Yeah, it's the equilibrium reaction O2 + O <--> O3.

    Basically, one wavelength of ultraviolet radiation causes O3 to form O2 + O. Another wavelength of ultraviolet radiation, shorter wavelength, causes O2 + O to form O3.
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    anyone got the paper or unofficial mark scheme?
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    hello????????????
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    Ha...
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    (Original post by AdamF)
    Ha...
    Mr. funny man,...tell me a joke?
 
 
 
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