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    (Original post by mrtum3000)
    Not sure I got crude oil.
    Also 3444 is what I got.
    Can you remember the question about methane? didn't it already say that its from natural gas and where did that come from? if you remember the question tell me pls
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    Landfill sites for sources of methane?
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    Are fossil fuels a source of methane??
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    (Original post by TheAnon121)
    Post your answers below, and we'll get an unofficial mark scheme!

    Random answers:
    Bond energies: -1276
    Explain why: Energy needed making bonds was greater than energy released breaking bonds
    Balance equation: 2 and 2 somewhere
    Efficiency of Kettle: Hydrogencarbonate ions thermally decompose to carbonate, then react with calcium ions to product a precitipates of calcium carbonate (limescale). Limescale is a bad conductor of electricity - more energy needed to heat water
    Hard water cleaner q: Calcium and magnesium ions replaced by sodium and hydrogen ions
    Benefits of hard water: contains calcium which strengthens teeth and bones
    Element that has low boiling point: F
    What happens in the mixture of gases? Ammonia is liquified, then cooled - Nitrogen and Hydrogen are recycled
    Specific heat capacity: 3444J
    How is methane obtained: Cows (?)
    Two boiling tubes: Tube A: fizzing because acid is dissolving calcium carbonate
    Tube B: calcium carbonate produced, solution goes cloudy
    Did this bond energy question have a triple bond between a carbon and an oxygen?
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    (Original post by 1jonam16)
    again i was thinking fractional distillation, wish i wrote it down. Are you simply amazing at chemistry? Haha you have the answers for everything.
    ahaha thanks mate but nah i just do stuff outside of school
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    For the decomposition of HCO3 ions, I don't know why but I said it produced calcium carbonate AS WELL as magnesium carbonate, then I said these were precipitates (scale) which covered the heating element of the kettle - making it a poor conductor
    Will I lose marks for saying magnesium carbonate?


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    (Original post by z1820)
    For the decomposition of HCO3 ions, I don't know why but I said it produced calcium carbonate AS WELL as magnesium carbonate, then I said these were precipitates (scale) which covered the heating element of the kettle - making it a poor conductor
    Will I lose marks for saying magnesium carbonate?


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    techiically you're still correct, though the spec doesn't mention magnesium carbonate.
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    (Original post by Sadxa)
    For the energy change I divided 3444 by 0.8 and go 4305? ANYONE ELSE?
    Yes I got that because 3444 is per gram whereas it wanted for 0.8g of alcohol not 1g


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    I think with the table the first blank was "white precipitate" for the one containing chloride ions, and the other two were "no result"
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    I really screwed up C3. C1 and C2 went really well. Just hoping that they alongside my 24% on the ISA will help get me that A*. I messed up the bond calculation and added the oxygen etc. 😩 I'll get a mark for method but that it's. I also messed up the methane question and said that the methane stays a gas but the N2 and H2 condense! I may get a mark because I said that the H2 and N2 are reused. That table question at the start threw me as well.


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    (Original post by milolj)
    Will you lose a mark for saying 1623 rather than -1623?
    Shouldn't do - in papers both were allowed
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    (Original post by Sadxa)
    Can you remember the question about methane? didn't it already say that its from natural gas and where did that come from? if you remember the question tell me pls
    it was apart from [something im unsure of] what is a source of methane?

    so far, answers seem to be: fractional distilation of crude oil, decomposition, flactulance, and possible the hydrogenation of a methyl group but idek if you could do that.
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    I am not sure about the bond energy questions, some are saying -1623 and some -1276, which is the right answer? Could someone please say why the other one is wrong also.
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    (Original post by Shaunarogerss)
    Shouldn't do - in papers both were allowed
    yeah. at GCSE they dont penalize you, but at Alevel they do so watch out
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    (Original post by dausa99)
    I really screwed up C3. C1 and C2 went really well. Just hoping that they alongside my 24% on the ISA will help get me that A*. I messed up the bond calculation and added the oxygen etc. 😩 I'll get a mark for method but that it's. I also messed up the methane question and said that the methane stays a gas but the N2 and H2 condense! I may get a mark because I said that the H2 and N2 are reused. That table question at the start threw me as well.


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    It was ammonia, not methane
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    THE BOND ENERGY WAS -711KJ WHAT WHAAATWHAAATT IT's -711KJ IM 100%SUREEEE ANYONE ELSE?
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    (Original post by Fr3dg)
    it was apart from [something im unsure of] what is a source of methane?

    so far, answers seem to be: fractional distilation of crude oil, decomposition, flactulance, and possible the hydrogenation of a methyl group but idek if you could do that.
    What about natural gas
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    (Original post by Sadxa)
    Can you remember the question about methane? didn't it already say that its from natural gas and where did that come from? if you remember the question tell me pls
    The SHC should be 4505 because it wa asking for per 0.8 gram
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    (Original post by BW999)
    It was ammonia, not methane
    I even wrote it wrong here 😩😩. I don't think I completely flunked it. Anything above 40 I'll take.


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    What do you guys reckon Grade Boundaries will be?


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