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    Hi
    Perhaps someone can help me with this question: how many electrons are involved in the pi bonding in benzene, between 2 adjacent carbons, and explain what each of the valency electrons in a carbon atom do (what type of bond sigma pi etc, what bonded with) in benzene.

    Any help appreciated, (and plus rep for you also)
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    (Original post by Zzzyax)
    Hi
    Perhaps someone can help me with this question: how many electrons are involved in the pi bonding in benzene, between 2 adjacent carbons, and explain what each of the valency electrons in a carbon atom do (what type of bond sigma pi etc, what bonded with) in benzene.

    Any help appreciated, (and plus rep for you also)
    Right. Each Carbon atom has 4 valency electrons. In Benzene, each Carbon atom has 3 sigma bonds - one with each of the adjacent Carbon atoms, and one with the Hydrogen atom. The remaining valency electron is in a p-orbital. The p-orbitals of the remaining valency electrons of all the Carbon atoms in Benzene overlap, forming pi bonds over the whole structure - this gives a region of high electron density above and below the ring. This means one electron from each Carbon, or 6 electrons altogether, are involved in the pi-bonds in Benzene.
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    (Original post by Zaphod77)
    Right. Each Carbon atom has 4 valency electrons. In Benzene, each Carbon atom has 3 sigma bonds - one with each of the adjacent Carbon atoms, and one with the Hydrogen atom. The remaining valency electron is in a p-orbital. The p-orbitals of the remaining valency electrons of all the Carbon atoms in Benzene overlap, forming pi bonds over the whole structure - this gives a region of high electron density above and below the ring. This means one electron from each Carbon, or 6 electrons altogether, are involved in the pi-bonds in Benzene.
    thanks alot, you cleared everything up for me
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    (Original post by Zzzyax)
    thanks alot, you cleared everything up for me
    Good! No problem
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    Anyone know what the stretch and challenge boxes are for in the book?
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    (Original post by master y)
    Anyone know what the stretch and challenge boxes are for in the book?
    Exactly what is says
    Its not needed for the exam, just there to make you think

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    (Original post by master y)
    Anyone know what the stretch and challenge boxes are for in the book?
    Its not on the spec so won't really be tested on, but I do physics OCR and apparently they once tested on something from the stretch and challenge boxes ... so i read it just in case

    Edit: why the neg rep :confused:
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    (Original post by Lilmzbest)
    Its not on the spec so won't really be tested on, but I do physics OCR and apparently they once tested on something from the stretch and challenge boxes ... so i read it just in case

    Edit: why the neg rep :confused:
    What OCR sometimes do is put in a question that relates to a stretch and challenge box, as normally the stretch-and-challenge is just putting some fact in context. This means exam questions can be linked to stretch-and-challenge, but you don't have to learn all the content in them necessarily, they'll give you the factual side, it's just learning to apply knowledge you've learned!
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    Just wondering if anyone has done a qualitative on redox and precipitation, and if so what is the actual title/what can ocr tell u about it? Thanks
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    i hate chemistry, i got my final coursework mark today 33/40 isnt even an A, even though i got 144/150 in jan F325, i will be very difficult to me to get an A*, our teacher gives us **** all help with the coursework unlike some others teachers in different schools, she just tells use vague areas to revise.coursework is unfair and flawed. how the **** can someone get a really high mark in in F325 and a B in coursework. anyone any advice of how i can justify to the examiner to award me an a star.
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    (Original post by Zzzyax)
    i hate chemistry, i got my final coursework mark today 33/40 isnt even an A, even though i got 144/150 in jan F325, i will be very difficult to me to get an A*, our teacher gives us **** all help with the coursework unlike some others teachers in different schools, she just tells use vague areas to revise.coursework is unfair and flawed. how the **** can someone get a really high mark in in F325 and a B in coursework. anyone any advice of how i can justify to the examiner to award me an a star.
    33/40 on coursework will correspond to 41 UMS, if my calculations are correct. Because you did so well in F325, you have bang on a 90% average between F325 and coursework. This means you need 81/90 UMS in the small exam - you got 144/150 in the big exam, it's perfectly possible! Don't give up hope, just work hard, you can get there
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    Hi guys, i have a qualitative coursework on investigating chemical reactions of some chromium compounds and then we have to identify two organic compounds, has anyone else done this? i don't know what i'm supposed to be revising :confused:
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    (Original post by physicshelp123)
    anyone got any tips for the determination of a formula practical???
    I'm doing this on friday! Anyone got any tips? We've basically been told nothing and I'm really worried. This is the evaluative if I'm not mistaken


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    Hey everyone, haha this has basically become a practical thread, so i was wondering if anyone has done a quantitative on free energy, and if so do they have any tips?
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    (Original post by kimsiclez)
    Nope, but I have an evaluative coming up on Electrode Potentials and a Quantitative the next day on Free Energy. Neither of which topics I fully understand (our teacher is rubbish). Wahey.

    Has anyone else's school left literally all the practicals until now? I mean, we've done a grand total of two so far. It's annoying that most of them seem to be related to topics towards the end of the syllabus.
    Hey, i was just wondering how the practical in free energy went, do you have any tips? Thank you, i would appreciate your help! I am pretty much like this atm --> :bricks:
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    (Original post by master y)
    Hey, i was just wondering how the practical in free energy went, do you have any tips? Thank you, i would appreciate your help! I am pretty much like this atm --> :bricks:
    Has anyone done evaluative on electrode potentials?
    i have recently done qualitative on chromium and a something on free energy change of formation, pm me
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    (Original post by Zzzyax)
    Has anyone done evaluative on electrode potentials?
    i have recently done qualitative on chromium and a something on free energy change of formation, pm me
    Hi want to revise
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    Hi,

    I recently printed out a copy of the huge F324 questions pack, but the answers copy had a block on it co it could be printed. I would be helpful if anyone could post a copy of the answers that i can print, i really want to start revising. :cool:

    The link of my questions pack: https://www.google.co.uk/url?sa=t&rc...45921128,d.d2k
    The link that wouldn't let me print: https://www.google.co.uk/url?sa=t&rc...45921128,d.d2k
    • Thread Starter
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    (Original post by master y)
    For an A you need 60/90 ums, and i think you can't get an A*...
    Hi want to revise
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    hey guys,
    im new but i was wondering if anyone can help me with this question...
    6) step by step to make mayonaise and...
    how long it takes to sepearate
 
 
 
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