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F334 (19/06/2013 9:00AM) - Salters Chemistry (Chemistry of Materials) Revision Thread Watch

  • View Poll Results: How did you find this paper?
    Very easy (~74 for an A)
    9
    18.75%
    Easy (~71 for an A)
    11
    22.92%
    Average (~65 for an A)
    21
    43.75%
    Hard (~61 for an A)
    6
    12.50%
    Very Hard (~58 for an A)
    1
    2.08%

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    how's everyone feeling about this exam?
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    (Original post by tasniaa)
    how's everyone feeling about this exam?
    Can't wait to do it. Compared to F335, this seems like a baby paper lol!

    Don't like the calculations though, and some of the biochemistry stuff can get weird

    Wbu?

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    (Original post by CureSam)
    18.2cm^3=0.0182dm^3
    0.0182*0.02=3.6*10^-4 moles of MnO4 (vol*conc=moles)
    3.6*10^-4*(5/2)=9*10^-4 (moles of H2O2 from the equation)
    That number of H2O2 is in 10cm^3, which is 0.01dm^3, giving a concentration of 0.09moles/dm^3, but the solution has been diluted by 10, meaning the original concentration 0.9mol/dm^3.

    Hope this helps!
    Thank you
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    C14H12O3 + 3OH- ----> (C14H9O3) 3- + 3H2O

    can someone please explain why we get C14H9O3) 3- ?
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    (Original post by tasniaa)
    how's everyone feeling about this exam?
    Much better than the first time I sat it, now that i've done F334 and F335.
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    (Original post by suncake)
    https://docs.google.com/file/d/1sdHM...it?usp=sharing

    Here you go. Yeah, ignore the incorrect scribbles then And excuse my awful scanning skills :lol:
    Brilliant, thanks for uploading. The paper actually didn't seem too bad, just those god-awful grade boundaries that put my two grades below where I needed.

    Could you explain 2(c)(iii)? I don't understand why ethanoic acid can hydrogen bond, but compound D only has pd-pd bonding.

    Thanks loads if you can.
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    (Original post by tsr1)
    C14H12O3 + 3OH- ----> (C14H9O3) 3- + 3H2O

    can someone please explain why we get C14H9O3) 3- ?
    3 OH groups that can donate 3 protons/hydrogen atoms to the base (OH-), so you're left with 3 negative oxygen atoms, giving a minus charge of 3.
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    (Original post by abzy1234)
    3 OH groups that can donate 3 protons/hydrogen atoms to the base (OH-), so you're left with 3 negative oxygen atoms, giving a minus charge of 3.
    3 OH on the alcohol will donate the H+ isn't? and thanks it was just in an equation form which made it harder for me to understand..
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    (Original post by tsr1)
    3 OH on the alcohol will donate the H+ isn't? and thanks it was just in an equation form which made it harder for me to understand..
    Yup and no problem
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    (Original post by tsr1)
    3 OH on the alcohol will donate the H+ isn't? and thanks it was just in an equation form which made it harder for me to understand..
    Be careful, a hydroxyl group on an alcohol won't donate a proton, only a cardboxylic acid.
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    (Original post by CureSam)
    You must have got like 90% ums on that?
    Nope 74/90 raw marks was 76/90 ums, so about 84% ums.

    (Original post by gingernat)
    Brilliant, thanks for uploading. The paper actually didn't seem too bad, just those god-awful grade boundaries that put my two grades below where I needed.

    Could you explain 2(c)(iii)? I don't understand why ethanoic acid can hydrogen bond, but compound D only has pd-pd bonding.

    Thanks loads if you can.
    No bother
    Carboxylic acids can form hydrogen bonds with each other because of the OH in the COOH group.


    Esters like compound D however do not contain an OH group, so don't have a suitable slightly positive hydrogen that can bond to the slightly negative oxygen on their carbonyl group. The hydrogens on the CH bond can't form H bonds because C and H have similar electronegativities, so it's not a polar bond and the H isn't slightly negative.

    I hope that made sense (and is actually correct :ninja:)... I hate intermolecular bonds :lol:

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    (Original post by CureSam)
    Be careful, a hydroxyl group on an alcohol won't donate a proton, only a cardboxylic acid.
    u make sense but the question said its an alcohol... confused
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    How do we calculate the rate of disappearance? Last question on Jan13
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    Now for F334.

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    (Original post by tasniaa)
    Now for F334.

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    Today's paper was good practice for mass spec


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    (Original post by tasniaa)
    Now for F334.

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    This paper is the bane of my life

    Got AAA in the AS units
    an A(*) in A2 coursework, a mid B in Chem of Design
    all the above being first attempts
    yet a E then D then C in chem of mateirals
    resulting in a B overall

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    does anyone have the Jan 2013 MARK SCHEME?
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    (Original post by 11hokj1)
    does anyone have the Jan 2013 MARK SCHEME?
    Here you go
    Attached Images
  1. File Type: pdf F334 Jan 2013.pdf (95.1 KB, 178 views)
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    (Original post by super121)
    Here you go
    Thank you. And good luck next week!
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    I'm literally sick with all the chemistry revision. Constantly regurgitating stuff one learnt from last year certainly ain't fun
 
 
 
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