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OCR Chemistry F322~ 4th June 2013~ AS Chemistry Watch

  • View Poll Results: How did you find the exam
    Hard A= 72
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    It was okay A= 76
    99
    35.87%
    Easy A= 79
    75
    27.17%
    Very Easy A=82
    60
    21.74%

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    ugh this exam is terrible , it like throws half the things you learn from the books out the window by asking so many questions in unfamiliar circumstances.
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    Do we need to know a mechanism for the hydration of an alkene?


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    (Original post by ImAz)
    Do we need to know a mechanism for the hydration of an alkene?


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    Not the actual mechanism, but need to know for example a molecule formed if hydrogen is added


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    (Original post by Jimmy20002012)
    Not the actual mechanism, but need to know for example a molecule formed if hydrogen is added


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    isnt hydration when steams added to make an alcohol
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    (Original post by needtosucceed=))
    isnt hydration when steams added to make an alcohol
    Yes, the other person described hydrogenation.
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    (Original post by Jimmy20002012)
    Not the actual mechanism, but need to know for example a molecule formed if hydrogen is added


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    I meant the reaction with steam in the presence of H3PO4 catalyst, 300•C and 60 ATM


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    (Original post by ImAz)
    I meant the reaction with steam in the presence of H3PO4 catalyst, 300•C and 60 ATM


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    yea you dont need to know the mechanism, just how to write an equation representing it
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    (Original post by ImAz)
    Do we need to know a mechanism for the hydration of an alkene?


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    Hydration using:
    steam
    Phosphoric acid
    300c
    60 atm
    Producing only ethanol

    C2h4 +h2o(g) ------> c2h5oh
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    (Original post by Gotzz)
    Yes, the other person described hydrogenation.
    Ohh did I explain hydrogenation?


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    (Original post by Jimmy20002012)
    Ohh did I explain hydrogenation?


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    Yup, you said adding hydrogen.
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    Thanks guys!

    Another question, how would you all go about discussing the processing of waste polymers? Eg separating, recycling, combusting and cracking? I'm struggling to summarise it


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    If anyone wants some help with chemistry I would recommend my youtube channel that does OCR bio and chem vids people seem to like them and I want to help. I have upload 4 more videos today

    http://www.youtube.com/user/MrBioTom1
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    Can someone please explain fragmentation and mass spectrometry...it confuses me so much!!!
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    (Original post by RachHill)
    Can someone please explain fragmentation and mass spectrometry...it confuses me so much!!!
    in a mass spectrum the peak furthest to the right is called the molecular ion peak, its m/z is equal to the molecular mass of the compound. all the other peaks may correspond to the possible fragments a molecule can split up into.
    so for example if you had ch3ch2ch2oh...the possible fragment ions could be ch3+, ch3ch2+ (or c2h5+) ch2oh+, basically u just split the molecule up whereever possible. these fragment ions would appear on a mass spectrum by their molecular masses. so for example on a mass spectrum there could be a peak at m/z=15, showing a ch3+ ion present (12+3=15), or if there was a ch2oh in a compound, the spectrum would show a peak at m/z=31.
    the main thing to remember is when given a long 10 marker on identifying compounds, use the molecular ion peak on the spectrum so you know the molecular mass of the compound. then if you know the empirical formula, which you've most likely worked out in the question already, you can work out the molecular formula hence helping to determine the structure of the compound.
    one thing to note is, although i said the peak furthest to the right is the molecular mass, if theres a tinyyy little peak next to it on the right then ignore it, its the taller peak thats the molecular ion peak.
    the other thing is uses of mass spec, which include mars space probes, breathalysers and pollution.
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    (Original post by needtosucceed=))
    in a mass spectrum the peak furthest to the right is called the molecular ion peak, its m/z is equal to the molecular mass of the compound. all the other peaks may correspond to the possible fragments a molecule can split up into.
    so for example if you had ch3ch2ch2oh...the possible fragment ions could be ch3+, ch3ch2+ (or c2h5+) ch2oh+, basically u just split the molecule up whereever possible. these fragment ions would appear on a mass spectrum by their molecular masses. so for example on a mass spectrum there could be a peak at m/z=15, showing a ch3+ ion present (12+3=15), or if there was a ch2oh in a compound, the spectrum would show a peak at m/z=31.
    the main thing to remember is when given a long 10 marker on identifying compounds, use the molecular ion peak on the spectrum so you know the molecular mass of the compound. then if you know the empirical formula, which you've most likely worked out in the question already, you can work out the molecular formula hence helping to determine the structure of the compound.
    one thing to note is, although i said the peak furthest to the right is the molecular mass, if theres a tinyyy little peak next to it on the right then ignore it, its the taller peak thats the molecular ion peak.
    the other thing is uses of mass spec, which include mars space probes, breathalysers and pollution.
    That was beautiful.
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    (Original post by ImAz)
    Thanks guys!

    Another question, how would you all go about discussing the processing of waste polymers? Eg separating, recycling, combusting and cracking? I'm struggling to summarise it


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    what you've written is pretty much the answer. most questions just ask you to state/describe how to dispose of them and advantages and disadvantages to them. so..
    - sorting AND recycling. you have to say both these words. helps conserve supplies of crude oil which is a finite resource.
    - incineration. benefits are that it reduces the need for landfill space which is in short supply, the process releases energy which can be used to heat the rest of the factory/for electricity/sold to the national grid. however they release toxic fumes eg. HCl(g), which can be reacted with bases or alkalis to neutralise them
    - crack them, then use the products to make plastics
    - use an chemical feedstock (i think?)
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    (Original post by yodawg321)
    That was beautiful.
    haha thanks!
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    Can someone upload the flash cards document which is in the Exam Cafe CD that comes with the ocr book please. Or send me a link to one that has been uploaded, because ive been looking on the net for ages and have had no luck finding it.
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    (Original post by Raju)
    Can someone upload the flash cards document which is in the Exam Cafe CD that comes with the ocr book please. Or send me a link to one that has been uploaded, because ive been looking on the net for ages and have had no luck finding it.
    there you go. i've put some of the other files too
    Attached Images
  1. File Type: pdf RES12_chembookanswers (1).pdf (243.8 KB, 59 views)
  2. Attached Files
  3. File Type: doc RES7_chemglossary (1).doc (322.0 KB, 63 views)
  4. File Type: doc RES8_chemcontentchecklist (2).doc (439.0 KB, 61 views)
  5. File Type: doc RES9_chemflashcards (1).doc (144.5 KB, 69 views)
  6. File Type: doc RES17_chemexaminerstips (1).doc (261.5 KB, 65 views)
  7. File Type: doc RES18_chemrypstretch.doc (191.5 KB, 53 views)
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    (Original post by needtosucceed=))
    in a mass spectrum the peak furthest to the right is called the molecular ion peak, its m/z is equal to the molecular mass of the compound. all the other peaks may correspond to the possible fragments a molecule can split up into.
    so for example if you had ch3ch2ch2oh...the possible fragment ions could be ch3+, ch3ch2+ (or c2h5+) ch2oh+, basically u just split the molecule up whereever possible. these fragment ions would appear on a mass spectrum by their molecular masses. so for example on a mass spectrum there could be a peak at m/z=15, showing a ch3+ ion present (12+3=15), or if there was a ch2oh in a compound, the spectrum would show a peak at m/z=31.
    the main thing to remember is when given a long 10 marker on identifying compounds, use the molecular ion peak on the spectrum so you know the molecular mass of the compound. then if you know the empirical formula, which you've most likely worked out in the question already, you can work out the molecular formula hence helping to determine the structure of the compound.
    one thing to note is, although i said the peak furthest to the right is the molecular mass, if theres a tinyyy little peak next to it on the right then ignore it, its the taller peak thats the molecular ion peak.
    the other thing is uses of mass spec, which include mars space probes, breathalysers and pollution.
    thank you this makes so much sense
 
 
 
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