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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?
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21
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2. (Original post by tasniaa)
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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3. (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
4. C14H12O3 + 3OH- ----> (C14H9O3) 3- + 3H2O

can someone please explain why we get C14H9O3) 3- ?
5. (Original post by tasniaa)
Much better than the first time I sat it, now that i've done F334 and F335.
6. (Original post by suncake)

Here you go. Yeah, ignore the incorrect scribbles then And excuse my awful scanning skills

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

7. (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.
8. (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..
9. (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
10. (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.
11. (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)

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

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 )... I hate intermolecular bonds

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12. (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
13. How do we calculate the rate of disappearance? Last question on Jan13
14. Now for F334.

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15. (Original post by tasniaa)
Now for F334.

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Today's paper was good practice for mass spec

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16. (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

17. does anyone have the Jan 2013 MARK SCHEME?
18. (Original post by 11hokj1)
does anyone have the Jan 2013 MARK SCHEME?
Here you go
Attached Images
19. F334 Jan 2013.pdf (95.1 KB, 178 views)
20. (Original post by super121)
Here you go
Thank you. And good luck next week!
21. 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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