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    I think ppl need to say it in the news about how unfair
    the exam was!!!! Too much reading and too much random questions!!!
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    does anyone actually know weather the answer to the last question was 66.6/7/8 or 33.? %?!
    Seems like there is an evenish spilt between the two answers..?
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    does anyone have any clues about the coursework ums? and what kind of raw mark (out of 40) would be an a?!
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    (Original post by HEC14)
    does anyone actually know weather the answer to the last question was 66.6/7/8 or 33.? %?!
    Seems like there is an evenish spilt between the two answers..?
    2.8g of brass, all the stuff before step 4 was irrelevant tbh.
    the equation for copper and KI is
    2Cu2+ 4I- -> 2CuI + I2

    then that was titrated against sodium thiosulphate with the eqation
    2S2O32- + I2 -> S4O62- + 2I-

    so 2 moles of thiosulphate = 2 moles of copper
    0.0298x0.1= moles of thiosulphate = moles of Cu2+
    =0.0029x10 = moles in the 250cm3, x 63.5 = 1.8923g/2.8x100 = 67.58...%
    answer asked for one decimal place so its 67.6%
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    (Original post by blush.ox)
    Lol i was basically just asking what 55 raw marks would equal in terms of UMS and you've answered my Q soo thankyou . Well good bye A in chemisty, it was never going to happen anyway :getmecoat:.



    Yes i know what you mean. I just wanted to know where i would stand with UMS based on if i got like 55 marks on this paper, which i've just looked through. That would help me see how many i would need in the F324 paper :/ to get an A, but it seems impossible, i might not even make the B :/.
    I think you usually multiply it by like 1.6-1.8 to get to UMS..
    Going by Jan's grade boundaries 65x 1.85 =120 UMS (ish)
    so 55x 1.85= 102UMS

    Although it's not quite like that..... this is just a (very) rough estimation!
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    (Original post by susan23)
    calculate your whole A level UMS marks...not indivitual grades in each module...because even if you get A grades in all your modules and practicals you STILL DONT GET AN A overall in A level....

    so add up your...

    unit 1
    unit 2
    practical AS
    unit 4
    unit 5 (assume)
    practical A2

    add them in terms of UMS!

    and if its 480 or above...it would be an A ...
    Well i've misplaced my marks for those units. Is there any way of getting hold of them. Do OCR send them out if requested and is there a fee?
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    (Original post by Rickesh)
    I didnt get that, nor did a few people I asked, they said its not a first order, as it didnt have a constant half life. when i worked it out i didnt get a constant half life?
    yeah i got second order
    but i messed the rest of the question up
    oh well a couple marks for stating the half life and saying it was second order hopefully
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    (Original post by wilsea05)
    2.8g of brass, all the stuff before step 4 was irrelevant tbh.
    the equation for copper and KI is
    2Cu2+ 4I- -> 2CuI + I2

    then that was titrated against sodium thiosulphate with the eqation
    2S2O32- + I2 -> S4O62- + 2I-

    so 2 moles of thiosulphate = 2 moles of copper
    0.0298x0.1= moles of thiosulphate = moles of Cu2+
    =0.0029x10 = moles in the 250cm3, x 63.5 = 1.8923g/2.8x100 = 67.58...%
    answer asked for one decimal place so its 67.6%
    Thankyou!
    This is exactly what i did
    However, all the very clever people at my school seem to have got half of my answer :/
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    (Original post by wilsea05)
    2.8g of brass, all the stuff before step 4 was irrelevant tbh.
    the equation for copper and KI is
    2Cu2+ 4I- -> 2CuI + I2

    then that was titrated against sodium thiosulphate with the eqation
    2S2O32- + I2 -> S4O62- + 2I-

    so 2 moles of thiosulphate = 2 moles of copper
    0.0298x0.1= moles of thiosulphate = moles of Cu2+
    =0.0029x10 = moles in the 250cm3, x 63.5 = 1.8923g/2.8x100 = 67.58...%
    answer asked for one decimal place so its 67.6%
    thats 9 marks gone... lol , do you remember what all the ionic equations where for 1 and 2?
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    (Original post by wilsea05)
    2.8g of brass, all the stuff before step 4 was irrelevant tbh.
    the equation for copper and KI is
    2Cu2+ 4I- -> 2CuI + I2

    then that was titrated against sodium thiosulphate with the eqation
    2S2O32- + I2 -> S4O62- + 2I-

    so 2 moles of thiosulphate = 2 moles of copper
    0.0298x0.1= moles of thiosulphate = moles of Cu2+
    =0.0029x10 = moles in the 250cm3, x 63.5 = 1.8923g/2.8x100 = 67.58...%
    answer asked for one decimal place so its 67.6%
    I got roughly 67.6% too. As soon as my calculator display showed this figure, I knew it was correct. The past paper questions seem to indicate this percentage anyway with brass questions.

    Do you remember what you put for the 3 ionic equations? and also how many marks were they worth?
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    (Original post by Killmepls)
    thats 9 marks gone... lol , do you remember what all the ionic equations where for 1 and 2?
    yeah you had to know that Cu2+ goes to Cu1+ otherwise you would've got the mole ratios wrong.

    urmmmmm

    step 4 was 2Cu2+ +4I- ->2CuI + I2
    cant remember the other 2 and cbaaa to figure them out haha
    can you remember how many marks the question was in total?
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    (Original post by Andygunner93)
    I got 33.8% as well
    same
    most ppl got 60 odd percent though, but if we do get it wrong hopefully we get ECF
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    (Original post by susan23)
    calculate your whole A level UMS marks...not indivitual grades in each module...because even if you get A grades in all your modules and practicals you STILL DONT GET AN A overall in A level....

    so add up your...

    unit 1
    unit 2
    practical AS
    unit 4
    unit 5 (assume)
    practical A2

    add them in terms of UMS!

    and if its 480 or above...it would be an A ...


    What would be a B?
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    (Original post by percy93)
    What would be a B?
    420 in the overall A level.
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    anyone know how many marks the Kc question was worth?
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    and also how many marks was it to work out the rate constant?
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    (Original post by pan_93)
    anyone know how many marks the Kc question was worth?
    6y?
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    can someone who remebers or has the paper put down all the marks required for each question?? thanks
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    (Original post by Flint_09)
    6y?
    6 marks?

    im just trying to add up my total....

    you know how many marks for working out the rate constant using the graph?
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    (Original post by pan_93)
    6 marks?

    im just trying to add up my total....

    you know how many marks for working out the rate constant using the graph?
    either 5 or 6 and for rate constant...7 or 9 marks.
 
 
 
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