he total mark for this paper was 105 with 9 questions. Please add to it as
much you can. The above is the archive, however this document can still
be edited for debate/additional information. Please keep in mind this is a
student made mark scheme, and these answers may not all be what is on
the...
Archive: A-Level Chemistry Paper 2 Unofficial markscheme: - Google Docs
Total Marks: 100/105
The total mark for this paper was 105 with 9 questions. Please add to it as
much you can. The above is the archive, however this document can still
be edited for debate/additional information. Please keep in mind this is a
student made mark scheme, and these answers may not all be what is on
the official mark scheme.
Topic for Paper 3: DNA, Chromatography, aspirin production
Question Answer Additional Information/Debate Mar
s
1 why use a conical I put it has a smaller opening than a what was the cotton wool in that diagram for 1
flask instead of a beaker so less gas lost?? You want to lolz it threw me off
beaker? lose gas? - I am pretty sure this is the I put that the liquid would be shallower with
larger surface areaso gas produced could
right answer, well it decreases the rate
escape quicker
of gas no loss so easier to measure
the rate. It doesn't reduce the rate of I put larger surface area for to heat mixture
gas loss as this only depends on the more evenly? I said this too
concentration of reactants
You dont want to have a large opening bc the
No splashing acid may be lost due to the bubbles forming.
This was jokes
Anything about swirling? I wrote swirling
Reactants don't stick to the side
what?????? they would stick a little
regardless
rate at 2 minutes. 0.5 g min-1? This is correct. A range of I got 0.02, you had to convert to mols - you 3
values typically accepted. I got 0.4 so didn’t have to, any appropriate units would be
yeah they’ll accept a range AS LONG fine
as they can see how you worked it out. I got like 0.0175 gs-1 - Same here - yeah just
rounded
G min-1 ?
Yeah but if u changed to seconds it Gmin-1 no? Is it not gmin-1 the graph was in
wouldn’t really matter as long as u put minutes
g per second
I converted the minutes to seconds and put
Mol Dm-3s-1 my units with seconds as well, any idea if
+ thats okay? Yes
, Suggest why (this question is already discussed a
chloroethanoic acid is little further down.)
stronger than ethanoic
acid
fill in rate 1.00 K=250 3
table 0.16 Yes i agree - needs to be 1.4 as all values
1.35 were to two sig figs
I beg someone write what the values Weren’t we they to 3 dp though?
were if they remember The rate of the first one was 1.00 so I’m
guessing 3sf of 2dp
empirical formula C6H10O3S2 Percentages dudbt add up to 100 fuck me 3
Didn’t even see the sulphur, fml same same i
thought i meant i was in the fuel area. YAY i
got this!!
the labelling distillation for the tube it was fractionating column 3
or glass beads
the bottom of the condenser was water
in
and top was water out
reject anti bumping granules
might accept silica BEADS
Draw a line for the Was the line of chloroethanoic acid to Cl is electron withdrawing, it polarises the 3
reaction with the left of the first line, but levelled off bond, weakens the O-H bond which releases
chloroethanonic acid at the same point? more H+ than ethanoic acid
Yes but it levelled out before, same Neg inductive effect?
height though. Ah ok. Chloroethanoic acid forms a more stable
Suggest why conjugate base?
chloroethanoic acid is a Dissociates more
stronger acid than Chlorine is more electronegative than
ethanoic acid. hydrogen so will withdraw electron
density form the carboxyl group
meaning that the O H bond breaks
more easily dissociating into H+
making the solution
more acidic
NMR Question? Use the integration values and the Was there a typo though? Regarding what? 5
ratios to identify the structure at two No dont think so, it was just because 2 of the 2
peaks. peaks were the same environment almost so 1
people got thrown off 2
Draw this structure.
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