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OCR Chemistry A Exam Thread (Breadth - May 27 2016 and Depth - June 10 2016) Watch

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    (Original post by JamieHarris1998)
    Thank You so Much !
    No problem! And good luck for tomorrow
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    (Original post by 11...)
    good luck everyone
    Thanks , you too.
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    (Original post by Bahcaci)
    Good luck to everyone, just don't panic, and you will be fine!

    I'm guessing everyone will be on here after the exam anyway 😉
    Haha, yeah, and 10 minutes after that, the unofficial mark scheme will be available. (Seriously, how do they make it that fast?)
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    are you allowed to write in bullet points for the 6 marker ?
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    (Original post by money-for-all)
    are you allowed to write in bullet points for the 6 marker ?
    Pretty sure it's no. I believe they're being pretty strict on the QWC in this new spec.
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    (Original post by Bahcaci)
    Chances are you will be asked to write the mechanism (free radical) of ozone depletion & also the name of the steps. And here it is:

    Initiation:
    Cl2 --> 2Cl•

    Propagation:
    Cl• + O3 --> ClO• + O2
    ClO• + O --> Cl• + O2
    (*Small note, notice the Cl• is reformed, so this reaction can go on for a long time, even after we stop use of CFCs)

    Termination:
    Cl• + Cl• --> Cl2 (main one!)
    Cl• + ClO• --> Cl2O
    ClO• + ClO• --> Cl2O2
    Do you mind explaining where the O in propagation 2 comes from?
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    (Original post by asinghj)
    Do you mind explaining where the O in propagation 2 comes from?
    He did it wrong. It should be:
    ClO• + O3 --> Cl• + 2O2
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    PLEASE HELP ME WITH THIS

    "1.40 g of calcium oxide was reacted with 50.0 cm3 of HCl in a polystyrene cup to produce a temperature rise of 10.0 degrees"

    Why is the total mass in q = mc (delta)t actually 51.4g not 50g [if density = 1.00 cm3]
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    (Original post by 11...)
    using the cgp revision guide would be really useful at this point to refresh yourself with all the content cos doing past papers can get a little boring after a while and of course they do not have questions on everything. something that was never asked before may turn up tomorrow who knows, so cgp guides are best for last minute prep
    LOL I made the mistake of using only a CGP guide for paper 1. I know, V stupid.
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    (Original post by nwmyname)
    PLEASE HELP ME WITH THIS

    "1.40 g of calcium oxide was reacted with 50.0 cm3 of HCl in a polystyrene cup to produce a temperature rise of 10.0 degrees"

    Why is the total mass in q = mc (delta)t actually 51.4g not 50g [if density = 1.00 cm3]
    for mass , you use the contents of everything you are heating,
    so you put 1.4g of CaO in a cup and then add 50cm3 (50cm3 = 50g)
    hence total mass of what you are heating = 50 + 1.4 = 51.4 grams

    let me know if that was a good enough explaintion^^
    if not, ill try to explain it better
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    (Original post by money-for-all)
    for mass , you use the contents of everything you are heating,
    so you put 1.4g of CaO in a cup and then add 50cm3 (50cm3 = 50g)
    hence total mass of what you are heating = 50 + 1.4 = 51.4 grams

    let me know if that was a good enough explaintion^^
    if not, ill try to explain it better
    OH ok.
    So you are looking at the enthalpy change of the ENTIRE mass of the solution including the CaO?

    I would be grateful if you explained it better.
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    (Original post by nwmyname)
    OH ok.
    So you are looking at the enthalpy change of the ENTIRE mass of the solution including the CaO?

    I would be grateful if you explained it better.
    b**ch dont diss my answer, i will get me mandem on ya

    cos' you were rude to me , now imma gonna go full ape on you bruv!!!

    .you dumb head, how can you not know what the anwer is

    Spoiler:
    Show
    lol, im only joking, sure i can explain it better,
    okay so, yes, you are correct.
    always measure the entire mass of solution.
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    (Original post by money-for-all)
    b**ch dont diss my answer, i will get me mandem on ya

    cos' you were rude to me , now imma gonna go full ape on you bruv!!!

    .you dumb head, how can you not know what the anwer is
    Spoiler:
    Show
    lol, im only joking, sure i can explain it better,
    okay so, yes, you are correct.
    always measure the entire mass of solution.
    haha that made me laugh!
    Thanks very much!
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    (Original post by money-for-all)
    b**ch dont diss my answer, i will get me mandem on ya

    cos' you were rude to me , now imma gonna go full ape on you bruv!!!

    .you dumb head, how can you not know what the anwer is
    Spoiler:
    Show
    lol, im only joking, sure i can explain it better,
    okay so, yes, you are correct.
    always measure the entire mass of solution.
    I thought m was the mass of surrounding and not the whole thing
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    (Original post by 4nonymous)
    He did it wrong. It should be:
    ClO• + O3 --> Cl• + 2O2
    Ok thx that explains it
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    (Original post by asinghj)
    I thought m was the mass of surrounding and not the whole thing
    oh my dayzzz fam,
    are you dizzy fam?

    you clown, i just said it is mass of what is being heated and then sidemen like you gotta go and confuse the whole mandem

    Spoiler:
    Show
    i'm pretty sure you have to measure the mass of what is being heated ? not the surrounding.
    cheers.
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    (Original post by money-for-all)
    oh my dayzzz fam,
    are you dizzy fam?

    you clown, i just said it is mass of what is being heated and then sidemen like you gotta go and confuse the whole mandem
    Spoiler:
    Show
    i'm pretty sure you have to measure the mass of what is being heated ? not the surrounding.
    cheers.
    Ok, I am ill the day before exam so won't even bother
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    (Original post by money-for-all)
    oh my dayzzz fam,
    are you dizzy fam?

    you clown, i just said it is mass of what is being heated and then sidemen like you gotta go and confuse the whole mandem
    Spoiler:
    Show
    i'm pretty sure you have to measure the mass of what is being heated ? not the surrounding.
    cheers.
    My friend, you might want to look at this question.

    http://alevelchem.com/aqa_a_level_ch....5/s351/03.htm

    I think in most circumstances, you measure the mass of the solution.
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    Which reaction mechanism is most likely to come up?
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    Does anyone have the mark scheme for the second set of the depth paper? H032/02
 
 
 
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