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    (Original post by Fractite)
    That was on our exam too (Unit 3) - with the nine elements - but it wasn't a 6 marker.
    We had 'how to carry out a titration' for our 6 marker - which was kinda easy, since they basically gave the answer to us.
    Yeah, I also had that. Did your paper have a specific heat capacity question? I'm seeing calculations for it however on my paper I don't remember a question asking for specific calculations however to compare the fuel of Methane and Decadane or something (I think).
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    (Original post by k0chia)
    Chemical Analysis and Ethanoic Acid
    Test tube 1 - effervescence/fizzing as the calcium carbonate reacted the ethanoic acid
    Test tube 2 - limewater turns cloudy as calcium carbonate + ethanoic acid -> calcium ethanoate + carbon dioxde. The carbon dioxide makes the limewater cloudy.

    Silver nirate in the presence of dilute nitric acid: white precipitate and no change
    Barium chloride in the presence of hydrochloric acid: no change and no change

    An acid(ic) catalyst is the production of esters
    Also, there was a question which required you to draw ethanoic acid and all you had to do was draw a double bond to an O then a single bond to an O then another one to an H.
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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 or Rb
    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: Natural gas
    Two boiling tubes: Tube A: fizzing because acid is dissolving calcium carbonate
    Tube B: calcium carbonate produced, solution goes cloudy
    Specific heat capacity question?
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    For the methane one i put from a bio gas generator aha oh dear
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    (Original post by Wisbey)
    Yeah, I also had that. Did your paper have a specific heat capacity question? I'm seeing calculations for it however on my paper I don't remember a question asking for specific calculations however to compare the fuel of Methane and Decadane or something (I think).
    We had a specific heat capacity question (work out energy transferred) and the answer was 3444J.
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    (Original post by JDoza)
    Specific heat capacity question?
    and there was the energy change question ? worth 3 marks no ? i got -580
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    (Original post by Fractite)
    We had a specific heat capacity question (work out energy transferred) and the answer was 3444J.
    I'm praying that we've done the different papers and that I haven't missed out a complete question...
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    (Original post by k0chia)
    It asked for the amount of energy released when 0.8g of the alcohol was burned. I found out the amount of energy released by heating up 50g of water. then finding how much energy would be released for each gram of water, then for 01.g of water and then when 0.8g of water was heated
    just read what you wrote, it asked for energy released from 0.8g of alohol, but you founder the energy needed "when 0.8g of water was heated", this arent the same
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    Anyone know where to get a full unofficial mark scheme
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    (Original post by Fr3dg)
    It's flourine, rubidium is solid at room temp flourine is gas at low temp.
    Damnit I was torn between fluorine and iodine
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    (Original post by powderpuff16)
    For the methane one i put from a bio gas generator aha oh dear
    this should be correct? the part of bio gas that is combustible and hence useful is the methane.
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    (Original post by Sadxa)
    For the energy change I divided 3444 by 0.8 and go 4305? ANYONE ELSE?
    That's for energy per gram and I don't think it asked you for that...
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    (Original post by powderpuff16)
    For the methane one i put from a bio gas generator aha oh dear
    I put rice farms :lol:
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    There was also a 6-marker on doing titration reactions. (That wasn't on the unofficial mark scheme). You basically put the steps to carry out the titration:

    put alkali in pipette and into conical flask
    acid in burette
    phenolphthalein or methyl orange indicator in conical flask
    add acid slowly until it starts to change colour
    add drop by drop until it goes from purple to colourless (phenolphthalein)
    do the same for acid B
    repeat until you have concordant results
    use formulas to work out concentration (like moles = [concentration x volume] / 1000 and concentration = [moles x 1000] / volume)
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    (Original post by Fr3dg)
    no, if it was one gram of water, you would have 1*4.2*16.4, which is 68.88J, but since it is the heating of 50g of water, then you times this by 50, to get 3444, if they wanted to know how much energy was released by 1 gram of FUEL rather than the 0.8g listed in the question, thenm you wouuld divide by 0.8, but thye didnt ask for this.
    So is the final answer ok as 3,444J?


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    (Original post by Roquebrune2014)
    So is the final answer ok as 3,444J?


    Posted from TSR Mobile
    yeah
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    (Original post by Fractite)
    There was also a 6-marker on doing titration reactions. (That wasn't on the unofficial mark scheme). You basically put the steps to carry out the titration:

    put alkali in pipette and into conical flask
    acid in burette
    phenolphthalein or methyl orange indicator in conical flask
    add acid slowly until it starts to change colour
    add drop by drop until it goes from purple to colourless (phenolphthalein)
    do the same for acid B
    repeat until you have concordant results
    use formulas to work out concentration (like moles = [concentration x volume] / 1000 and concentration = [moles x 1000] / volume)
    how many marks do you think I would lose if I put the acid in the pipette and alkali in the burette?
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    (Original post by Wisbey)
    I'm praying that we've done the different papers and that I haven't missed out a complete question...
    Was your very first question about ethanoic acid and carbonates and describe two things that you'll see?
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    (Original post by surina16)
    how many marks do you think I would lose if I put the acid in the pipette and alkali in the burette?
    Well, it's a 6 mark quesiton, so you aren't really marked so much on what's correct and isn't but your writing technique for the method.
    If everything else is correct, you'll probably only drop one mark as that's only really a minor mistake.
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    (Original post by Purplepizza988)
    WOW! How could you remember all that?!
    I put the exact same for the SHC question but lots of people are saying that you have to use 50g instead of 0.8g...
    I read my reply again allow the typos please . It said to calculate the amount of energy released by burning 0.8g. They have the equation and everything so just getting 3444J would be around 1-2 marks
 
 
 
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