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OCR Salters Chemistry F335 12th June 2013 Exam revision thread Watch

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    How many marks was the polymerisation question
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    (Original post by Sujman)
    How many marks was the polymerisation question
    2; reaction type and reason for this.
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    Grade A has always been between 80-85, so I think this paper will be around 83-85. If OCR decide to do a crazy jump in grade boundaries like they did for F334 this January... Then God help us all!
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    (Original post by Pandora's Box)
    I think I did something like that. Cause originally the salt/acid ratio was 1/1 so if half the acid reacts and gets turned into salt, you get 1.5/0.5 which equals 3? So Ka = [H+] x 3? pH came out as 4.2 or something I think, can't remember..
    I can't remember the number, but that was my thought process too!
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    (Original post by Sujman)
    How many marks was that
    it was only one but i probably lost it now cause i think you have to write 100% atom economy.

    Do you know how many marks the mass spec questions were
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    Classifying reactions:

    First one was about isocyanate synthesis - "What type of reaction is step 2?" A single H was removed, as far as I could tell... I put elimination, no idea what the actual answer is

    Second one was about the polymers - addition, as no small molecule eliminated.



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    For the insecticide did anyone put about it going into drinking water and affecting humans


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    Guys what you put for the sea shells question?
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    (Original post by suncake)
    Classifying reactions:

    First one was about isocyanate synthesis - "What type of reaction is step 2?" A single H was removed, as far as I could tell... I put elimination, no idea what the actual answer is

    Second one was about the polymers - addition, as no small molecule eliminated.



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    It was a 2 marker I'm sure for the type of reaction in step 2, and the reactants were Br2 and NaOH... with HBr added... I put nucleophilic substitution, but that seems wrong now
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    (Original post by suncake)
    Classifying reactions:

    First one was about isocyanate synthesis - "What type of reaction is step 2?" A single H was removed, as far as I could tell... I put elimination, no idea what the actual answer is

    Second one was about the polymers - addition, as no small molecule eliminated.



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    same "addition, as no small molecule eliminated."

    yes I noticed a H atom was lost so I put dehydration but that's H20 so who knows...
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    (Original post by HTB)
    what did people put for the 'industrial use of hydrogen'? (i think that was the question!)
    Haber process
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    inhibitor question???
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    [QUOTE=Futuristicmedic;43116454]2 HCOOH + caco3 --> co2 + h2o + (Hcoo)2ca


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    damn i got this wrong, do you think i cn still pick up a mark for writing
    HCOOH + CacO3 ---> CO2 + CA(HCOO-)2 + OH
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    (Original post by suncake)
    Acid + salt = water, though!

    I put exactly the same curly arrows as you.

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    True, but wouldn't that be the same in a normal Ka equation since there is salt and acid but you don't assume it reacts? I don't really know :confused:

    I really wasn't sure though...maybe there will be two options! (Very wishful thinker)
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    what grade would you get if got ?

    105 -

    108 -

    110 -
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    (Original post by Futuristicmedic)
    Harber process


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    Yeah I put that too
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    (Original post by abzy1234)
    It was a 2 marker I'm sure for the type of reaction in step 2, and the reactants were Br2 and NaOH... with HBr added... I put nucleophilic substitution, but that seems wrong now
    the rectants where naoh
    the group went from NHBR to -N-BR so i put reduction just as a guess
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    Someone do an unofficial ms


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    (Original post by C.JTop)
    the rectants where naoh
    the group went from NHBR to -N-BR so i put reduction just as a guess
    I put reduction too


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    (Original post by C.JTop)
    (Original post by Futuristicmedic)
    2 HCOOH + caco3 --> co2 + h2o + (Hcoo)2ca


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    damn i got this wrong, do you think i cn still pick up a mark for writing
    HCOOH + CacO3 ---> CO2 + CA(HCOO-)2 + OH
    I'm a little confused. How do you know it's H2O and CO2 rather than H2CO3 or H+ and HCO3- :confused:

    Edit: Oh. Never mind. I'm being stupid.

    Also, do people think if matters if we put charges on (HCOO)2Ca? Like HCOO- Ca2+ -OOCH?
 
 
 
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