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

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    Hard A= 72
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    Easy A= 79
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    Very Easy A=82
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    (Original post by lllllllllll)
    you'll be really really really lucky if they allow HFCs since the specification says:

    (g) outline the role of green chemistry in
    minimising damage to the environment by
    promoting biodegradable alternatives to
    CFCs, such as hydrocarbons and HCFCs;
    CO2 as a blowing agent for expanded
    polymers (see also 2.4.2).
    Omg, so HCFCs is the correct answer?? I put that then crossed it out :|
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    (Original post by Gotzz)
    Omg, so HCFCs is the correct answer?? I put that then crossed it out :|
    On a functional level, HFCs and HCFCs are near-identical, except HFCs do not dissociate at any point to form potentially harmful radicals. HFCs will very likely be fine. Think about it like this, CFCs are used for their unreactivity so removing chlorine ought to reduce reactivity and risk of damaging the ozone (due to high C-F bond enthalpy). See attached if you are still unconvinced : http://www.sartep.com/chem/chartsand...bondenergy.cfm .
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    (Original post by fluker6696)
    On a functional level, HFCs and HCFCs are near-identical, except HFCs do not dissociate at any point to form potentially harmful radicals. HFCs will very likely be fine. Think about it like this, CFCs are used for their unreactivity so removing chlorine ought to reduce reactivity and risk of damaging the ozone (due to high C-F bond enthalpy). See attached if you are still unconvinced : http://www.sartep.com/chem/chartsand...bondenergy.cfm .
    Sorry, I meant I crossed it out and put something completely different, not changed it to HFCs. I thought HCFCs weren't biodegradable which is why I changed my answer.
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    There was a question in the AS unit 2 exam, June 4th and it was 'name a biodegradable alternative to CFC's.' would HFC's be an okay answer? thanks
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    (Original post by LaurenceM)
    There was a question in the AS unit 2 exam, June 4th and it was 'name a biodegradable alternative to CFC's.' would HFC's be an okay answer? thanks
    see above post
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    (Original post by Gotzz)
    Omg, so HCFCs is the correct answer?? I put that then crossed it out :|
    Same!


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    (Original post by scienceboy16)
    Same!


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    I wrote HCFs and then it sounded wrong, didn't know whether to put instead HFC So last min of the paper I settles for HCFC

    Thank goodness!!



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    There was also a question involving colours, something to do with bromine and a double bond. Was the correct answer orange to colourless?


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    (Original post by LaurenceM)
    There was also a question involving colours, something to do with bromine and a double bond. Was the correct answer orange to colourless?


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    Yep, it was

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    (Original post by 344302)
    I wrote HCFs and then it sounded wrong, didn't know whether to put instead HFC So last min of the paper I settles for HCFC

    Thank goodness!!



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    Like an idiot i wrote biodegradable polymers


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    Ahh, damn it! Just realised I forgot to put the plus on the molecular and fragment ions


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    (Original post by scienceboy16)
    Like an idiot i wrote biodegradable polymers


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    OMG same!
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    (Original post by LaurenceM)
    Ahh, damn it! Just realised I forgot to put the plus on the molecular and fragment ions


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    How did U guys workout the fragment ions:fuhrer:

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    (Original post by Freddy-Francis)
    How did U guys workout the fragment ions:fuhrer:

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    From what I can remember it either mentioned sulfur or had peaks around 32 which meant it was sulfur. Then divided each peak by 32 and it gave the amount of sulfur atoms in it
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    (Original post by BeyondCure)
    From what I can remember it either mentioned sulfur or had peaks around 32 which meant it was sulfur. Then divided each peak by 32 and it gave the amount of sulfur atoms in it
    Yeah, it mentioned that it was sulfur.
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    (Original post by BeyondCure)
    From what I can remember it either mentioned sulfur or had peaks around 32 which meant it was sulfur. Then divided each peak by 32 and it gave the amount of sulfur atoms in it
    Damn it. I lost 3 marks

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    It had an ion peak of 256 i think and it said it was sulphur. It then asked what the formula mass of the sample was, so 258/32.1 = around 8, meaning it would have been S8. Next question said something on lines of "state the molecular ion responsible for the peak at 128 m/z" which 128 / 32.1 = 4. So molecular ion is S4+
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    (Original post by SuperCat007)
    What do you mean by structural formula? My understanding of that is that it is the same as the displayed formula which does show double bonds, as does the skeletal formula. How did you draw the structure without showing the double bonds? Unless you mean the molecular formula which was C4H8O (I think... Can't remember), in which case the question said suggest the structure. If you have only quoted the molecular formula then you won't get the marks for suggesting a structure as the molecular formula doesn't show possible structures for the molecule.
    So I put this: CH3CH2CH2COH for the aldehyde. I know it doesn't directly highlight the C=O double bond but is it a structural formula.
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    (Original post by germankid101)
    So I put this: CH3CH2CH2COH for the aldehyde. I know it doesn't directly highlight the C=O double bond but is it a structural formula.
    The shows butanol. The aldehyde would be CH3CH2CH2CHO I think
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    (Original post by dawg)
    The shows butanol. The aldehyde would be CH3CH2CH2CHO I think
    Yupp, aldehydes always have a "CHO" ending
 
 
 
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