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    (Original post by conzag123)
    I wasnt sure about this question at all and left it until the very end to think over it..... I was tempted to write down what you wrote as I too have seen this in a past paper. however, as it was to do with fermentation (i hope that's what the question was referring to now i think of it), i said the atom economy will always be the same as co2 will always be produced as the reaction is very specific to the zymase enzyme found in yeast so percentage yield is more important so you can make more ethanol, considering co2 is always going to be produced.

    it was one of those "i dont really know what im writing" type of answers but i thought it made sense when i read what i'd written :confused:

    anyone want to comfort me and tell me if this will get any marks??? didnt it say what do you think is most important, so you could put eiter as long as it was justified???? (not sure tbh)
    I put exactly what you put, and it made sense to me. I wrote something like with fermentation, you will always get CO2 produced, therefore the atom economy will never be 100%. Also, in the production of ethanol it is more important to have a good percentage yield (ie: high efficiency of converting reactants into products) because this will enable a high yield of ethanol, which is wanted in industrial production.
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    (Original post by bagelbe)
    nooooooooo I think I got the other two right though? But the empirical formula didn't agree with the m/z value so I just worked it out from the m/z value because I go into a bit of a panic :L
    I thought i did it wrong at that stage, but u had to times the empirical formula by 2 to get the molecular formula
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    (Original post by Ttawwab)
    Yeah, I put Methyl Propanoate instead, because I was stupid and got the correct formula for Ethanol, then for some reason thought it was methanol. Hopefully we'll still get the marks.
    yeah i really hope we do.
    i think i've lost so many marks on not being so specific
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    (Original post by SmithytheDrummer)
    Just out of interest, what did you put for the international cooperation one, and the one about dynamic equilibrium in a car?
    I put insufficient heat to reach dynamic equilibrium
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    (Original post by Joseppea)
    I realise that now! :ashamed:
    If it makes you feel any better, I numbered my carbons wrongly because I was rushing and put trigonal planar! :hugs:.
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    I wasn't sure for why a dynamic equilibrium can't occur in a car to put there's no closed system or macroscopic properties (such as temperature) don't remain constant. I wasn't sure whether a car exhaust was a closed system or not, so in the end I went for the macroscopic properties. It was basically asking the conditions for a dynamic equilibrium.
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    What a ridiculous paper for a chemistry exam.
    Why bother revising half the theoretical (interesting) stuff when they're going to throw a bunch of essay style questions about sustainability and the environment, which was a tiny part of the syllabus.
    I really need an A in this paper, and don't know if I got it because I know i messed up the radical question (didn't know NO2 was a radical) and missed a 1 or 2 marks on the last question (had a silly moment and did the empirical formula for X wrong - still got it right overall though)
    It now just depends on if they deem my paragraphs on sustainability and "international co-operation" correct (hardly shows skill at chemistry).
    [/rant]

    I'm pretty annoyed at OCR, first the wrong question in the D1 exam yesterday, now a really pathetic chemistry paper. I guess I'll feel better about it soon.
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    Was the last question ethyl propanate? and what was the nitrogen monoxide catalyst reaction?
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    i put percentage yield becuase it means that more reactents are converted into products ?
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    What was the shape for the second carbon? and shapes on unit 2?! I did not revise that...
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    (Original post by racheatworld)
    I put exactly what you put, and it made sense to me. I wrote something like with fermentation, you will always get CO2 produced, therefore the atom economy will never be 100%. Also, in the production of ethanol it is more important to have a good percentage yield (ie: high efficiency of converting reactants into products) because this will enable a high yield of ethanol, which is wanted in industrial production.
    thank you now reading it it does make sense to me and i hope we will get the marks as i feel we should (not trying to sound cocky though...) - i mean what's there really to fault with this answer???

    i just felt a bit insecure about it as all of my friends said atom economy!

    overall i thought it was neither a difficult nor an easy paper but i was pushed for time hopefully i will have got an A
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    Why do people expect someone to have the paper not even two hours after it has finished? haha. Especially a student, like the majority of people on here...
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    (Original post by conzag123)
    I wasnt sure about this question at all and left it until the very end to think over it..... I was tempted to write down what you wrote as I too have seen this in a past paper. however, as it was to do with fermentation (i hope that's what the question was referring to now i think of it), i said the atom economy will always be the same as co2 will always be produced as the reaction is very specific to the zymase enzyme found in yeast so percentage yield is more important so you can make more ethanol, considering co2 is always going to be produced.

    it was one of those "i dont really know what im writing" type of answers but i thought it made sense when i read what i'd written :confused:

    anyone want to comfort me and tell me if this will get any marks??? didnt it say what do you think is most important, so you could put eiter as long as it was justified???? (not sure tbh)
    I put down "because the enzyme zymase/yeast stop working after a alcohol concentration of 14% focusing on atom economy would be more practical or something like that." >>>this isn't even logical. :rolleyes:
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    (Original post by bagelbe)
    nooooooooo I think I got the other two right though? But the empirical formula didn't agree with the m/z value so I just worked it out from the m/z value because I go into a bit of a panic :L
    If you got the other 2 right you won't have lost many marks. I wouldn't worry, you can afford to lose quite a few marks and still get an A. At first, my m/z didn't add up but then I realised I hadn't put 2 oxygens in the empirical formula to make it C3H6O2, and then realised it fit.
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    (Original post by DeanFoley)
    If it makes you feel any better, I numbered my carbons wrongly because I was rushing and put trigonal planar! :hugs:.
    :eek: Just made me remember my answers to that question

    For the first one I put E/Z isomerism, crossed it out, put Pyramidal.... CROSSED THAT OUT and put tetrahedral. (I think I was right in the end?)

    For the second bit I put trigonal planar.... then crossed it out and put pyramidal!

    Chemistry is definitely the exam with the most silly mistakes this year for me! Though I still have physics to mess up on :cool:
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    (Original post by bagelbe)
    nooooooooo I think I got the other two right though? But the empirical formula didn't agree with the m/z value so I just worked it out from the m/z value because I go into a bit of a panic :L
    Yeah there was a teeny tiny peak at like 47 or something but it didn't work so I used the big one at 46 to get CH3CH2OH
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    (Original post by Cookies and Cream)
    What was the shape for the second carbon? and shapes on unit 2?! I did not revise that...
    Shape of the second carbon was trigonal planar, because there were three bonded regions, the first was tetrahedral because there were four carbons.
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    I worked out and wrote the formula of propanoic acid right but i wrote it was ethanoic acid by mistake because in was rushing. How many marks would I lose?
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    (Original post by lolo-x)
    The other use of methanol methylated spirits?

    Yes, thats what I wrote. but methylated spirits are solvents, which was mentioned in the question? I think.. Feel freee to correct me. In fact, PLEASE correct me :P
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    (Original post by conzag123)
    thank you now reading it it does make sense to me and i hope we will get the marks as i feel we should (not trying to sound cocky though...) - i mean what's there really to fault with this answer???

    i just felt a bit insecure about it as all of my friends said atom economy!

    overall i thought it was neither a difficult nor an easy paper but i was pushed for time hopefully i will have got an A
    I don't think it will matter whether you choose percentage yield or atom economy, as long as you can justify it. And we seemed to have justified it well, so we should get the marks! (If there's not some dodgy part of the question we seemed to have mis-read, which I don't think there was )
 
 
 
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