AQA CHEM 2 June 2012 paper and unofficial mark scheme

OMG I completely didn't see the question Q6,Q7 where you get 3 marks for drawing some curly arrows what have i done!!??

thank you so much

Would rep you again if I could
Thanks a lot

OMG I completely didn't see the question Q6,Q7 where you get 3 marks for drawing some curly arrows what have i done!!??

Hi all
As promised, here is a link to the paper, I've scanned it and uploaded to my skydive on hotmail. It may take a while to load, but you should be able to download and print it off as you wish
June 2012 paper
I'll write my interpretation of the answers in the next post

holy **** FFS i didnt see that either OMG OMG OMG OMG EASY MARKS GONE :O:O:O:O

OMG I completely didn't see the question Q6,Q7 where you get 3 marks for drawing some curly arrows what have i done!!??

(ii) silver(I) chloride, Ag+ + Cl- --> AgI, ppt dissolves (3)

UNOFFICIAL MARK SCHEME - please point out any errors (done with paper in front of me and I'm a teacher...)

1(a) steeper line, ending twice as high (2)
(b) less steep line, ending 2/5 as high (2)
(c) steeper line, ending at same level (2)
(d) concentration of reactants decreases with time, hence frequency of collisions decreases as does the rate (2)
(e) 2 H2O2 --> 2 H2O + O2 (1)
(f) The HBr is not used up (1)

2(a)(i) -49 (3)
(ii) it is an element (1)
(b) increases, 4 moles gas --> 2 moles gas, eqilibrium shifts right to oppose the change (3)
(c) increases, reaction is endothermic, equilibrium shifts right to oppose the change (3)
(d)(i) no net carbon produced (1)
(ii) CH3OH + 3/2 O2 --> CO2 + 2 H2O (1)
(iii) 3 H2 + 3/2 O2 --> 3 H2O (1)
(e) q = 4389 kJ, DH = - -399 kJ/mol (3)


3(a) balancing equation (1)
(b) P4 = zero, H3PO4 = +5 (2)
(c) Add up Ar values to show they are different to 5dp (1)
(d)(i) speeds up rate of reaction without being used up (1)
(ii) addition of water (1)
(iii) CH3CH=CH2 + H2O --> CH3CH(OH)CH3, propan-2-ol (2)

4(a) Forms brittle TiC (1)
(b)(i) 2 FeTiO3 + 7 Cl2 + 6 C --> 2 FeCl3 + 2 TiCl4 + 6 CO (1)
(ii) TiCl4 + FeCl3 + 7 Na --> Fe + Ti + 7 NaCl (1)
(c) Cu2+ + Fe --> Cu + Fe2+, Cu2+ ions reduced as they gain electrons (2)
(d) 2 O2- --> O2 + 4e (1)

5(a)(i) Ba + 2 H2O --> Ba(OH)2 + H2 (1)

(ii) reactivity increases (1)

(b) Mg(OH)2 (1)

(c) Barium meal / X-ray tracer, insoluble (2)

6(a)(i) Cl2 --> 2 Cl.
CH2Cl2 + Cl. --> .CHCl2 + HCl
.CHCl2 + Cl2 --> CHCl3 + Cl. (3)
(ii) UV light, Free-radical substitution (2)
(b)(i) CHCl3 + Cl2 --> CCl4 + HCl (1)
(ii) CHCl3 contains C-H bonds, no C-H absorption at 2850-3300 (2)
(c) CFC's - UV light breaks C-Cl bond, makes Cl. radicals
Cl. + O3 --> ClO. + O2
ClO. + O3 --> 2 O2 + Cl. chain reaction
2 O3 --> 3 O2 (4)
(d)(i) CH2=C(F)CF3 (1)
(ii) it contains no C-Cl bonds (1)

7(a)(i) elimination mechanism (3)
(ii) E hex-3-ene (H's on opposite sides) and Z-hex-3-ene (H's on same side) (2)
(iii) Same MF and SF, different arrangement of atoms in space (2)
(b) H2SO4 electrophilic addition mechanism (4)

8(a) Safety - NaOH is corrosive, Environmental - Process 2 uses CO2 from local factory, less CO2 emissions/global warming (2)
(b)(i) Nucleophilic substitution with :OH- (3)
(ii) BCA (3)
(c) Fermentation, 35oC, Yeast, aqueous, anerobic (4)
(d) primary alcohol, acidified potassium dichromate(VI)
CH2(OH)CH2CH2CH2OH + 4[O] --> HOOCCH2CH2COOH + 2 H2O (3)

9(a)(i) Iodine/I2, Cl2 + 2 I- --> 2 Cl- + I2, redox (3)
(ii) silver(I) chloride, Ag+ + Cl- --> AgI, ppt dissolves (3)
(b)(i) H+ + Cl- --> HCl, HCl (2)
(ii) 2 I- --> I2 + 2e-
H2SO4 + 6 H+ + 6e- --> H2S + 4 H2O
H2SO4 = oxidising agent, yellow solid = sulfur/S/S8 (4)
(iii) NaOH reacts with H+, equilibrium shifts right to make more H+ and opppose the change
bromine is used in small quantities

It is I dunno whether to think I'm stupid for missing out the easy mark or are they just daft for not making it clear and drawing out attention to the questions at the bottom ya know by actually putting lines in for us to WRITE ON.