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    (Original post by frivolousfretter)
    Whoops, I said the forward reaction is exothermic for the 3 mark question at the bottom, because my solution enthalpy calculated was exothermic. Would that be CE=0 or could I still potentially get a mark from it?
    It was exo
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    (Original post by Hopefulmedic15)
    Trust me, avoid having to resit during your gap year at all costs 😂

    Last exam tomorrow and then I'm free :3
    Bio 5?? And yhh chemistry has had me so stressed I won't even be happy I get an A on this exam. Made so many silly mistakes 😬 But I think I'll hopefully scrap an A* on this paper and it'll even out to an A overall.


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    blue for Cr2+ (rather than blue solution) wouldn't be wrong? I thought it just said what was the colour observed
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    Tbh im looking at getting a c in chem so looks like ill be resitting. FeelsBadMan


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    (Original post by Azzer11)
    There seems to be nobody that did the same as us, so maybe we ****ed up?
    Are you talking about the enthalpy and entropy calculations? If so, you're right! We didn't **** up, the rest did
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    (Original post by vinchy)
    Negative electrode: check cgp brown book pg 185
    its the other way round
    Negative electrode is the anode which is where oxidation occurs.
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    (Original post by girl :D)
    It was exo
    I mean, for the explain that question below it - was the forward reaction exothermic?
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    (Original post by rimstone)
    i only put Zn (not H + , acid consition ) + just blue ( didnt put solution ) for the CR2+ Q.
    pretty sure you wouldn't have to put solution cos it already said that it was aqueous
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    Oh **** yeah, it asked for the enthalpy change of the reaction not the enthalpy of formation so you didn't have to divide by 2 lool
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    (Original post by Aethrell)
    Would Zn/HNO3, blue be acceptable answers for that Cr2+ question? Didn't put solution and just guessed the acid
    I'm pretty sure it said state the colour so hopefully you didn't have to mention solution. I wrote just blue too
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    Predicted grade boundaries for an A*? I think the exam wasn't piss easy but it wasn't insanely difficult either

    There were a few traps like dividing the enthalpy stuff and the last questions. Also a lot of people lost marks on the first question for writing sulfur

    Overall I think 83 A*



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    (Original post by rimstone)
    paper wasnt too hard, pretty normal for CHEM5, i would say it was as easy as last years.]
    But i made a ton of little mistakes,
    firstly i only put Zn (not H + , acid consition ) + just blue ( didnt put solution ) for the CR2+ Q.
    for the H cell, i didnt put any electrons in the half equation, just forgot in the mist of the exam ... not idea why since im great at these,
    for the Question from NA-P, i put P and S. I did both forming into acid, i got P wrong IMO, didnt recheck teh Q and put S down as well... do i lose marks for that ?
    i put p4010 + 6h2o ----> 4HPO4 + 2 H+ , i knew it was wrong since the oxi numbers didnt add up on HPO4, but in later Q it said HPO4 was an acid, so i was conflicted, so didnt put H3PO4, and put HPO4 ( didnt even put the fing charge ) thouhght if i put S down ill get the hard, but yurns out you cant do S, so i have both.
    floped the born-harber, didnt double some numbers, since there were 2 K ..... silly mistake, should have known better.
    Put teh wrong sing for enthropy, made it + not - .

    might have got some more Q's wrong. didnt do the calculation for the purity, since i always get those wrong, after chem4, i wasnt willing to waste time. Also had the wrong equation, made C204- = co2, instead of CO, even though i knew full well it was CO,... but co2 was easier to worth with .

    overall might get a B or a C.. made a ton of silly mistakes. With my horrible CHEM4, im either getting a C best case, or D worse.... fun 2 years of chem

    With the colour of the Cr2+ complex putting blue would be just fine I think as it only asked for the colour and not the physical state.
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    Is there an unofficial marks chem for either this or chem4?
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    (Original post by Jabbasalacious)
    blue for Cr2+ (rather than blue solution) wouldn't be wrong? I thought it just said what was the colour observed
    yeah agreed; solid.
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    (Original post by frivolousfretter)
    I mean, for the explain that question below it - was the forward reaction exothermic?
    yup im pretty sure because u get a value of -155 which is exothermic
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    (Original post by rimstone)
    paper wasnt too hard, pretty normal for CHEM5, i would say it was as easy as last years.]
    But i made a ton of little mistakes,
    firstly i only put Zn (not H + , acid consition ) + just blue ( didnt put solution ) for the CR2+ Q.
    for the H cell, i didnt put any electrons in the half equation, just forgot in the mist of the exam ... not idea why since im great at these,
    for the Question from NA-P, i put P and S. I did both forming into acid, i got P wrong IMO, didnt recheck teh Q and put S down as well... do i lose marks for that ?
    i put p4010 + 6h2o ----> 4HPO4 + 2 H+ , i knew it was wrong since the oxi numbers didnt add up on HPO4, but in later Q it said HPO4 was an acid, so i was conflicted, so didnt put H3PO4, and put HPO4 ( didnt even put the fing charge ) thouhght if i put S down ill get the hard, but yurns out you cant do S, so i have both.
    floped the born-harber, didnt double some numbers, since there were 2 K ..... silly mistake, should have known better.
    Put teh wrong sing for enthropy, made it + not - .

    might have got some more Q's wrong. didnt do the calculation for the purity, since i always get those wrong, after chem4, i wasnt willing to waste time. Also had the wrong equation, made C204- = co2, instead of CO, even though i knew full well it was CO,... but co2 was easier to worth with .

    overall might get a B or a C.. made a ton of silly mistakes. With my horrible CHEM4, im either getting a C best case, or D worse.... fun 2 years of chem

    Im sure c2o4 did make c02?
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    (Original post by Aerosmith)
    Are you talking about the enthalpy and entropy calculations? If so, you're right! We didn't **** up, the rest did
    Are you sure? It made sense to me in the exam but I'm not so confident now.
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    (Original post by OloMed)
    The overall equation is:

    H2 + 1/2 O2 ----> H2O

    imcreasing conc of either H2 or O2, or increasing pressure, would all shift the equilibrium to the RHS, so EMF increases
    I got that because for standard enthalpy i used SO2+1/2O2.> SO3
    GOT -98.5KJMOL-1
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    (Original post by K2Cr2O7)
    Didn't the question say find delta S and delta H for THIS reaction. Meaning they were asking for values for the exact equation they gave ???

    Im not sure as i cant remember the question exactly.
    (Original post by Azzer11)
    There seems to be nobody that did the same as us, so maybe we ****ed up?
    The question asked you to calculate the STANDARD enthalpy and entropy change, which was asked on Jan 13 I believe and you had to divide by two.
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    last exam tomorrow im gna spend all day watching game of thrones and eating pizza lol im soo exhausted
 
 
 
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