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    (Original post by In One Ear)
    Can either of you remember the question for the number of litres of petrol one? My bro sat the exam today and wasn't sure about his method so I want to go through it with him but he can't remember the exact statements...
    It was something like the EU wants to reduce CO2 emissions by 2020 by 5.4 X 10^5 g(not sure on the exact figure). They gave the equation for complete combustion of octane, and said that how many liters of petrol less would a car have to burn in 2020 (then told us that a litre=700g).


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    Does anyone have any ideas of grade boundaries? Stressed as I found the exam ok but so many people are saying it was amazing and now I'm concerned about grade boundaries. I need an A and I know I've definitely lost around four marks but it could be more than that as I make silly little mistakes and it's likely I've lost some along the way :/
    Hope you guys all found it ok though!!


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    (Original post by GetOverHere)
    It was something like the EU wants to reduce CO2 emissions by 2020 by 5.4 X 10^5 g(not sure on the exact figure). They gave the equation for complete combustion of octane, and said that how many liters of petrol less would a car have to burn in 2020 (then told us that a litre=700g).


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    it was 5.6x10^5 not 5.4


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    (Original post by nadrxj)
    Anyone else get something like 14g for the percentage yield question?
    Yeah I got that like 14.08g
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    (Original post by NervousBoy)
    Yeah I got that like 14.08g
    Got 14.05, did you round on your workings at all?


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    (Original post by drandy76)
    Got 14.05, did you round on your workings at all?


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    i got 14.05 as well but i put my final answer as 14, did it ask for specific d.p?
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    what did everyone get for the question where you had to work out the number of monomers in the polymer? was it 50000/70 or 50000/71?
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    (Original post by AJtheconfusedcat)
    what did everyone get for the question where you had to work out the number of monomers in the polymer? was it 50000/70 or 50000/71?
    I got 50000/70 which came to like 715 or something, but I'm guessing you get ECF marks if your monomer was different
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    (Original post by nadrxj)
    I got 50000/70 which came to like 715 or something, but I'm guessing you get ECF marks if your monomer was different
    i did 50000/70 as well but it was 714? and i left it with some decimals, did it have to be a whole number?
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    Anyone else scared about the crazy high grade boundaries?

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    (Original post by GetOverHere)
    It was something like the EU wants to reduce CO2 emissions by 2020 by 5.4 X 10^5 g(not sure on the exact figure). They gave the equation for complete combustion of octane, and said that how many liters of petrol less would a car have to burn in 2020 (then told us that a litre=700g).


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    Thanks! I agree with the others then, assuming that figure is right, should be 249 litres of petrol required.
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    I don't think it went that well, it was ok but not amazing like most people found it! What grade do you guys think 60marks will be roughly?


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    (Original post by AJtheconfusedcat)
    i did 50000/70 as well but it was 714? and i left it with some decimals, did it have to be a whole number?
    I rounded my answer up to 715 because of the wording of the question, I guess if you left it unrounded that would also work but if you rounded it down then they wouldn't be able to make at least 50,000 they would end up making less. I'm probably wrong though.
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    Think I dropped a few marks in some calculations but generally happy with how it went!!!

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    (Original post by AJtheconfusedcat)
    i did 50000/70 as well but it was 714? and i left it with some decimals, did it have to be a whole number?
    I got 714 but left it as that

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    (Original post by UnknownAnon)
    Anyone else scared about the crazy high grade boundaries?

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    Yes! Hahah

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    (Original post by NervousBoy)
    This is what I remember from my calculations.

    Magnesium Mass : 0.38 g or something along that

    CO +1602
    Volume: 259.09 Litres
    Enthalphy of Nonane: -230 something
    Enthalphy of Reaction using Temp change: -34.7 or similar
    Repeat Units: 50000/70

    Let me know what you guys got
    Wasnt it 50,000/68 because it was an Mr of 70 for the hydrocarbon but only 68 for the monomers?
    Ignore me, i ****ed that bit up. I forgot that only the dounle bond breaks the hydrogens stay put. My bad.
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    (Original post by NervousBoy)
    This is what I remember from my calculations.

    Magnesium Mass : 0.38 g or something along that

    CO +1602
    Volume: 259.09 Litres
    Enthalphy of Nonane: -230 something
    Enthalphy of Reaction using Temp change: -34.7 or similar
    Repeat Units: 50000/70

    Let me know what you guys got
    yeah that's all correct i got that too
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    (Original post by Hunnybeebee)
    I got 714 but left it as that

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    i think you have to leave it as 715 despite that 50000/70 =714.285 because 714 monomers will not make Mr=50000 they will only make polymers with Mr=49980 but I think they will still allow 714 : )
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    (Original post by jirapat121)
    i think you have to leave it as 715 despite that 50000/70 =714.285 because 714 monomers will not make Mr=50000 they will only make polymers with Mr=49980 but I think they will still allow 714 : )
    I calculated it and looked at the decimal place so rounded down. Hopefully the twitter account will upload the paper tonight may be!

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