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Edexcel Chemistry Unit 4 &5 watch

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    Hello, How did every1 find these chemistry papers. I thought they were ok. Unit 4 was doable, unit 5 was a little harder, and messed up a lot. If I revised my ass off then i would off aced these papers. Compared to previous years, these were ok, but still tricky.

    I think Physics A level is the hardest and not Chemistry, if you can remeber **** in chem then yur okay, but hey who am i.

    I only did Chem 5 as I'd done Chem 4 during Jan.

    I must say it's probably the easiest Chem 5 paper compared to the two previous ones. No lead-acid battery, no rusting, no melting-point composition graphs, no other mechanisms apart from the benzene one (which was common) and no diazotization. It was a nice paper, in my opinion, and I had 30 minutes to check.

    I remember the calculations the most: 0.09 mol dm^-3 for the concentration of iron II sulphate, and 0.02 mol^-2 dm^6 s^-1 for the value of k.

    I heard that Chem 4 did not have a Born-Haber cycle question this year. Outrageous! Heheh.

    m8
    how did u get ur calc ??

    i was quite chuffed with chem 4. Considering i am pants at chem, i think i did ok in both. there were some rough questions in both chem 4 and chem 5. in chem 4, the one about enthalpy of solution business. I thought that was difficult and in chem 5, the one about recrystallisation for 6 marks!!! dirtyness. i also messed up a few other ones like the last question in unit 5 about NMR. I totally forgot that all it takes into account was the Hydrogens, but instead, i started talking about peaks for ALL of the bonds!!!! damn!!! well, surely i'll get 2 marks out of 4 for actually naming the 6 peak on the propanone and the 1 peak on the propanal... hopefully i got a B on both papers, but if i'm lucky, a low A on unit 4.

    I am so annoyed with myself. After the module 5 exam, I remembered I forgot to put the sulphuric acid in the first question.

    I also mucked up the rate equation question. The NO increased 9 times! So I put a factor of 3. Oh dear - it was suppose to be 2!

    I hope they'll still give me a few marks for that question...

    It was a fair paper overall, just a few things that are annoying and hard to remember

    Anyway, good luck for Tuesday, for the most feared and hardest chemistry paper

    5 was a nice paper

    but i ****ed up

    The examiners were quite cunning actually for the kinetics question in Chem 5. It starts of asking 3 rate equations of order 2. But then the following part to it involves an experiment with a rate equation of order 3.

    Originally posted by Unregistered
    m8
    how did u get ur calc ??
    For the iron (II) sulphate one I don't remember the values exactly but it was a ratio of 1:5 between manganate and iron 2+ ions so working out the number of moles for manganate x 5 and then dividing by the volume added (25 cm^3) gives 0.09 mol dm^-3.

    For the kinetics question, just substitute in one set of results into the rate equation and you get k = {0.02/(0.1^2 x 0.1)} which gives 0.02. The units worked out to be: mol dm^-3 s^-1/(mol dm^-3 x mol dm^-3 x mol dm^-3) = mol^-2 dm^6 s^-1 as units for k. Thus, the answer is 0.02 mol^-2 dm^6 s^-1.
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    Oh my god i made some dumb mistakes today. 5 was ok except the transition metal bit and the rate stuff- im so thick, i wrote that one of the compunds was to the order 3 and it was supposed to be 2! AAAAAAAAAARRRRRRRRGGGGGGGGGGGHHH HHH! And the organic monomer molecule i messed up as well. Ah well just the synoptic to look forwards to now.
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    Also, if you get the rate equation wrong, then does that mean that you automatically get the mark for the unit wrong as well- even if it matches your answer?
    Or do you get follow through marks?

    I did both paper today but both papers were very nice. I did well in unit 4 but not unit 5.

    I spent so little time revising the unit 5 so that was the reason why I don't remember too much. I wish I can do better on the C5 if I spend MORE time revising the whole unit 5.

    Now looking forward to the synpotic paper. Hope it's not too hard than physics... hahaha...

    Best of luck with the sypnotic paper, mate!

    Love Amy

    Wanna chat you can email me at [email protected]

    Argh. Synoptic next week.

    what does everybody need in synoptic to get their grade??


    i need 70%!! too bloody much for synoptic
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    i need like 92 percent in synoptic for over all .. A... today started praying like u neva seen before.. dont excpect revision to get me trhu.. ITS IMPOSSIBLE

    Originally posted by Unregistered
    what does everybody need in synoptic to get their grade??


    i need 70%!! too bloody much for synoptic
    Hey hey, same here, I guess we both got the same internal assessment marks for practical. Didn't realise until recently that getting a good internal mark pays off so much, phew. 70% is still indeed quite challenging for Chem Synoptic. Oh well. Hopefully it's as easy as Chem 5 today.

    I'm sure many people sat this paper.

    hey there was a question on chromium 3+ ion in mod 5. well it said when u add excess aq Ammonia that a "Solution A" was formed. We were taught that Cr didn't react in excess ammonia however did react in excess NaOH Cr(OH)6 3-, so what was the right answer to this question? did i read it improperly or was this actually an erratum that wasn't read out at our centre. i think i didn't read the question properly, but someone tell me
    thanks

    I am not sure if this is the correct answer, but I think and I wrote Cr with excess ammonia is "No reaction"

    People tell me is ligand exchange but i think that is rubbish.

    Of course its not an error. They want to test to see if you are willing to say "No reaction"!

    Don't worry about it and focus on the 6b!

    that's hell!

    ok so no reaction was the answer. but why did it say solution A? that seemed stranged and muddling. i.e implying that there was a solution formed, i knew there couldn't have been from what i was taught. Annoying question!

    thats cause u had to write that cr(OH)2 was formed which was the green ppt that remains in excess

    could anyone do the polymerisation and how do u get the three isomers of trinitrobenzene?
 
 
 
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