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    (Original post by zahre)
    Oh crap. Didnt include the diluted part. Is it wrong to just say sodium hydroxide?:mad:
    Unfortunatly yes, because water is require to hydrolyse the bond.
    However, hey may accept it, provided that you didn't mention conc. NaOH at all !!
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    (Original post by Kartace)
    the water comes from the dilution, the OH- ions are catalysts

    Dilute alkali hydrolysis produces Carboxylate ion and NH3
    If it were a dilute acid hydrolysis the an ammonium ion NH4+ and carboxcylic acid would be produced
    Yeah you're right for both. I made a mistake with the alkali hydrolysis I think.
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    (Original post by Darthdevidem)
    Ohhhh for the reaction one.

    I put measure how fast H+ ions are used up with PH METER?!?!?! IS this right!?!
    Yeah. I wrote PH, then concentration of H+ ions, then I wrote measured with PH Meter. I've seen this question a lot and they accept that.
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    (Original post by jam277)
    Yeah you're right for both. I made a mistake with the alkali hydrolysis I think.
    Don't worry, if it makes yo feel any better i protonated both of the amine groups in the zwitterion question for some reason !!! sae it in a past paper once ! I came out and i felt like an idiot.
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    I think there are two possible answers for that questions, the H+ method with Acid/Base Titration, and the Iodine method with the Thiosulphate Redox Titration.

    For the Zwitterion, I only ionised one amine group and the one carboxylic group, is that right?
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    Have been trying to rememeber the question I wanted to ask about for ages and I've remembered it!

    It was about the "green" ferrous something or other and why something was more environmentally friendly.

    Maybe I was just being silly but were they talking about "green" as in the colour of a precipitate or "green" as in you know the environmentally friendly eco conscious "green"? I got very confused...
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    (Original post by MyJunkIsYou)
    Have been trying to rememeber the question I wanted to ask about for ages and I've remembered it!

    It was about the "green" ferrous something or other and why something was more environmentally friendly.

    Maybe I was just being silly but were they talking about "green" as in the colour of a precipitate or "green" as in you know the environmentally friendly eco conscious "green"? I got very confused...
    Lmao, I'm pretty sure green as in 'environmentally friendly'. That's what I wrote about anyway :p:
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    (Original post by MyJunkIsYou)
    Have been trying to rememeber the question I wanted to ask about for ages and I've remembered it!

    It was about the "green" ferrous something or other and why something was more environmentally friendly.

    Maybe I was just being silly but were they talking about "green" as in the colour of a precipitate or "green" as in you know the environmentally friendly eco conscious "green"? I got very confused...
    This was a another Vauge question, I was thinking does it mean Green as a percipitale cos it was Iron 2+ or green as in enviromental friendly.
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    (Original post by hidden_desire)
    Lmao, I'm pretty sure green as in 'environmentally friendly'. That's what I wrote about anyway :p:
    haha okay. Well originally i wrote about how the precipitate formed is green in colour but then i crossed it out and wrote environmental stuff instead
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    (Original post by RobG93)
    I think there are two possible answers for that questions, the H+ method with Acid/Base Titration, and the Iodine method with the Thiosulphate Redox Titration.

    For the Zwitterion, I only ionised one amine group and the one carboxylic group, is that right?
    Yeah but you did the amine one not the amide one right?

    I think we were only meant to ionise just one amine group as the definition of a zwitterion is that a proton can be transferred between COOH group and NH2 group. (not two protons)
    (Original post by hidden_desire)
    Lmao, I'm pretty sure green as in 'environmentally friendly'. That's what I wrote about anyway :p:
    It was green as the product of the other cell was toxic so harmful to environment, while the iron cell product (out green cell) was just rust which isn't harmful to the environment

    lol thats what i wrote
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    (Original post by xPixie)
    Haha, well.. I did go into the exam not knowing much, so if I get anything above a D, I'd be really happy tbh Chem, I thought was alright actually.. Some bits made me think WTF?! But overall it was a good paper How did you find it?
    Ha, It was alright. A bit synoptic though, and the polyacid question threw me. I know a few little mistakes I've made though. Hopefully it's an A!
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    Can somebody confirm: did the last question ask for the name of the complex or the shape? What did people get for the equation where excess hydroxide ions were added?
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    (Original post by zahre)
    Can somebody confirm: did the last question ask for the name of the complex or the shape? What did people get for the equation where excess hydroxide ions were added?
    Shape not name 100%.

    Fe3+ + 3OH- = FE(OH)3

    I will cry if thats wrong.
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    (Original post by Darthdevidem)
    Shape not name 100%.

    Fe3+ + 3OH- = FE(OH)3

    I will cry if thats wrong.
    You're right for sure. It said that a red-brown precipitate was formed. Fe3+ is red brown and the precipitate is also red brown and iron(III) hydroxide is a precipitate. I'll cry if I'm wrong. I've lost like 10 marks for sure. Hopefully that'll be around 84/90
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    (Original post by zahre)
    Oh crap. Didnt include the diluted part. Is it wrong to just say sodium hydroxide?:mad:
    thats not correct.. the right answer is water.. H20.

    because:

    acid + water = carboxylate ion + oxonium ion.
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    (Original post by ManPowa)
    thats not correct.. the right answer is water.. H20.

    because:

    acid + water = carboxylate ion + oxonium ion.
    NAOH gives you a carboxylate ion too( and NA- floating around).

    (Original post by jam277)
    You're right for sure. It said that a red-brown precipitate was formed. Fe3+ is red brown and the precipitate is also red brown and iron(III) hydroxide is a precipitate. I'll cry if I'm wrong. I've lost like 10 marks for sure. Hopefully that'll be around 84/90
    Me too I reckon I've lost 15 marks, few more here n there. HOpefully 67-70/90

    I guess thats barely an A.
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    (Original post by Darthdevidem)
    NAOH gives you a carboxylate ion too( and NA- floating around).



    Me too I reckon I've lost 15 marks, few more here n there. HOpefully 67-70/90

    I guess thats barely an A.
    Usually a high C or a low B is an A so you probably got a medium A. I wanna get at least 90% in this though I'm not sure whether I got that. I'm sure I've got at least 80% though.
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    When wil the question paper and mark scheme for yesterday's paper be out?
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    Well thats two chemistry papers im re-sitting in summer

    july 2010
    and jan 2011...
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    Your teachers can view the paper 24 hours after the exam, the actual mark scheme won't be up for ages (nov. I think) on a secure website, so it can be used as a mock. Such a hard paper! x
 
 
 
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