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    AQA YOU BEAUTIES!!!

    I forgive you for CHEM4!! That was such a nice paper. The only bit I didn't get was the 3 marks for the chromium thingy where it went to a solid and gas, damn it!

    I'm expecting at least 95 for UMS cap though, so I hope I haven't dropped much more than those 3 marks.
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    (Original post by neevtrehan)
    How did you do it?
    Equation for moles manganate to c2o4-, from what I can remember it was 2:5
    Question gave conc and vol of managanate, so multiply for moles, then divide by two times by 5 for c2o4- moles, x10 for volume. Then divide by 3 as the molecule had 3 mols of c2o4-. Find mr (460 something i think?), Find the mass by moles x mr. Then do mass / mass given in the question x100 for percentage
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    (Original post by openmyeys)
    Accidentally did MnO4- to Mn3+.... got confused with dichromate, will I lose all the 7 marks?
    No way, if you did every other step correctly, you'll probably still get 5.
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    Am the only one that found it awful?
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    Yeah, it's 2:5 and you also have to divide by 3, because 3 molar solution of potassium iron oxalate reacting, to get 94.4%.
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    (Original post by Fibsy)
    Predicted grades boundaries? Easy paper, so what's the highest it's ever been for an A and A*? I need an A* to bump up my grade so this is a bit annoying

    Posted from TSR Mobile
    The grade Boundaries will be similar to last year, similar paper, with a C2O4- redox titration like last year, so I think it would be 85 for a A* ... and 76/77 for a A, 69 for a B.
    They should be higher this year, the paper was not super easy or difficult
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    Doesn't get much easier than that
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    Your right
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    I used the wrong moles ratio cause I couldn't balance my equation so I ended up with 1:2. But I'm pretty sure I did all the other steps correctly, how many marks do you think I lost?
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    I got like +1910 or something for the Born Haber cycle wtf
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    (Original post by Cadherin)
    AQA YOU BEAUTIES!!!

    I forgive you for CHEM4!! That was such a nice paper. The only bit I didn't get was the 3 marks for the chromium thingy where it went to a solid and gas, damn it!

    I'm expecting at least 95 for UMS cap though, so I hope I haven't dropped much more than those 3 marks.
    Solid is cr(h2o)3(oh)3 and the gas is co2, it's M3+ with co32- reaction
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    Wanted a nice exam paper but I thought that was a bit too nice, grade boundaries are going to be sky high
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    If there is a lot of crossing out but the answer was correct.... Is it ok
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    (Original post by Sufyxyz)
    I think I got like 80.9 for the purity
    so did i, apparently there was something with the moles on iron - like the molarity was 3 or something
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    Very easy paper! Definitely a bit harder than last years though so I would guess grade boundaries will be similar or perhaps 1/2 marks lower


    Posted from TSR Mobile
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    (Original post by Fibsy)
    I found it mostly easy but I don't want to get my hopes up. The questions i didn't get were:
    What is the effect on emf of increasing pressure of oxygen?
    Ditto for effect of increasing Pt surface area
    Conditions under which E for something was something (I put in circuit with standard hydrogen electrode with 298K etc)

    For the titration calculation I out something like 96%? Sneaky of them to make the compound have three C2O4 ions in

    Posted from TSR Mobile
    If you look at the equation it's just le chatelliers so inc pressure means more h2o produces which means more redox and less oxidation and so emf inc.

    Sa has no effect

    conditions are 298k, 100kpa(although not sure if relevant there) and then 1m solution
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    Anyone else get something like +1910 for the Born Haber cycle?
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    (Original post by zombaldia)
    Solid is cr(h2o)3(oh)3 and the gas is co2, it's M3+ with co32- reaction
    Yeah, *******s, I should've picked up on that.
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    Enthalpy for lattice dissociation was 2328? And did we have to work out enthalpy of solution, this was negative answer wasn't it?
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    (Original post by greenmath)
    Wanted a nice exam paper but I thought that was a bit too nice, grade boundaries are going to be sky high
    Yeah I agree. wasted a day of revision. I'm ****ed for c4
 
 
 
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