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    Guys, what were the 5 marks for propene?

    My guesses

    Mention of Pi bond (1)
    Sideways overlap of p orbitals(1)
    Pi bond has high electron density, allowing it induce other molecules to break the Double bond (1)
    Mention of sigma bonds (1)
    8 sigma bond in the molecule (1)
    120 degree bond angle in unsaturated part of molecule but 109.5 degree in saturated (1)

    All I could think of :/




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    (Original post by owen.williams)
    Yeah, I winged that question and drew a cup with some insulation and a lid with the thermometer through a hole in the top.
    Ah good. I was worried I had to draw a burette with HCl in it or something, pheww.


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    (Original post by RasputinReborn)
    Guys, what were the 5 marks for propene?

    My guesses

    Mention of Pi bond (1)
    Sideways overlap of p orbitals(1)
    Pi bond has high electron density, allowing it induce other molecules to break the Double bond (1)
    Mention of sigma bonds (1)
    8 sigma bond in the molecule (1)
    120 degree bond angle in unsaturated part of molecule but 109.5 degree in saturated (1)

    All I could think of :/




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    I think you had to relate it to reactivity too if I recall correctly. But yes I used the information we'd been taught on the structure of ethene and applied it to the double carbon bond in propene.
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    (Original post by owen.williams)
    I think you had to relate it to reactivity too if I recall correctly. But yes I used the information we'd been taught on the structure of ethene and applied it to the double carbon bond in propene.
    Yeah, but all I could think of for reactivity is the Pi bond inducing other molecules with its high electron density, which makes sense since there was a mechanism underneath for that very process.


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    For the 2 reactions in Section A, did you guys say you would use a gas syringe and colorimeter?


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    Perhaps one of the more difficult questions on the paper was the reason why Efan got a lower enthalpy change then Sian. Did anyone else say that Mg is now an excess and HCl isn't, therefore HCl is used in the calculation, and then use maths to back it up?


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    For the energy profile with the Ea and enthalpy change labelled in section A, was it a exothermic or endothermic reaction?
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    (Original post by RasputinReborn)
    I had 3-Chloro-2,4-dimethylpentanoic acid

    Edit: I just looked on the Internet and the compound you listed doesn't seem to exist.

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    I got the same
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    (Original post by Lil670)
    For the energy profile with the Ea and enthalpy change labelled in section A, was it a exothermic or endothermic reaction?
    I had endothermic, as it was the opposite of respiration which was exothermic.
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    Guys, do you remember that question on compound A, B and C?.
    I think the first answer was dehydration,
    Then it asked you to draw 2 possible isomers, I wrote Butan-1-ol and Butan-2-ol, then it asked you for the displayed formula of C (when compound A reacts with acidified potassium dichromate) what did everyone put for that? I wrote Butanoic acid :/


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    (Original post by RasputinReborn)
    Perhaps one of the more difficult questions on the paper was the reason why Efan got a lower enthalpy change then Sian. Did anyone else say that Mg is now an excess and HCl isn't, therefore HCl is used in the calculation, and then use maths to back it up?


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    Yes I did exactly this, then I used the ΔT = 14.5°C and worked out Elfed's ΔH as something like -303KJmol-1 and Sian's as -364KJmol-1. I realised after though that we can't actually assume that Elfed's ΔT would be the same as Sian's... so I'm not 100% sure I backed my statement up with the correct maths.
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    (Original post by owen.williams)
    Yes I did exactly this, then I used the ΔT = 14.5°C and worked out Elfed's ΔH as something like -303KJmol-1 and Sian's as -364KJmol-1. I realised after though that we can't actually assume that Elfed's ΔT would be the same as Sian's... so I'm not 100% sure I backed my statement up with the correct maths.
    We better get As for getting this bs right. Usually it's "heat lost to surroundings" or something easy like that, haha.
    I just calculated the number of moles of Mg and HCl for Efan and said Mg was in excess

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    (Original post by RasputinReborn)
    We better get As for getting this bs right. Usually it's "heat lost to surroundings" or something easy like that, haha.


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    I'm wondering what the grade boundaries are going to be like...I've just been looking and the hardest CH1 since 2011 was the 2014 paper and you needed 71% for an A, and for CH2 it was 2015 and you needed 66% for an A. Both this year's papers have been considerably harder than those past papers so we can cross our fingers and hope they're lower than those.
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    (Original post by elliekmorgan62)
    I put propan-1-ol and propan-2-ol, and then propanone for compound C. I think as long as its a ketone, aldehyde or carboxylic acid they have to give the mark.
    But when it reacted with H2SO4 it gave C4H8, so how did you get propanol?
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    (Original post by RasputinReborn)
    But when it reacted with H2SO4 it gave C4H8, so how did you get propanol?
    Tbh I can't remember. Maybe I did put butanol. My mind tends to blank after exams.
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    (Original post by owen.williams)
    Yeah, I winged that question and drew a cup with some insulation and a lid with the thermometer through a hole in the top.
    Do u have to show the lid or?
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    (Original post by ChemSinceDaay...)
    Do u have to show the lid or?
    Yes, labelled too.


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    Yeah bro, literally everything you've asked, "did anyone put this" yeah we've put the same stuff down. Well done😉 that's exactly what I did and worked it out to -606.somethingkJ per Mole and then also said that the hcl was less concentrated i.e 0.5molar to 0.1molar so reaction is slower and more heat loss resulting in less temp mesured on the thermometer so the %error of that thermometer is greater.
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    I'm pretty sure I got the percentage error one correct, not sure though. Isn't percentage error
    MAX-MIN/2 x100.
    So I did 0.2-01/2x100=5% bang on which seems a decent figure? Not sure it's right but like she has potential as they say😏😂😂
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    (Original post by Elliottmanwaring)
    I'm pretty sure I got the percentage error one correct, not sure though. Isn't percentage error
    MAX-MIN/2 x100.
    So I did 0.2-01/2x100=5% bang on which seems a decent figure? Not sure it's right but like she has potential as they say😏😂😂
    Seems more correct than 100% 😂
    Honestly, that percentage error was probably the hardest maths question on the entire paper.


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