OCR Chemistry H432/02 - Synthesis and Analytical Techniques Unofficial MS

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DoubleDoors
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Can't really remember many of the questions now, so please contribute!

Fox Corner


MCQ Section [15 marks, 1 mark each]
1. Silver Nitrate
?. Z isomer was the one with Cl and F on the same side.
?. 5 chiral carbons


Section B [85 marks]

Name the alcohol/alkene [1 mark]
Hex-3-en-1-ol (ACCEPT 1-hydroxy hex-3-ene)

Define Stereoisomers [1 mark]
Molecules with same structural formula, different spatial arrangement.

Purifying the benzene based solid and assessing purity [6 mark]
-Filter under r.pressure
-Recrystallise (hot solvent and cool)
-Filter under r.pressure (cool solvent)
-Dry
-Melting point compare with known mp (data book/database)
% yield - ???

Unknown Aromatic Compound - molecular formula [2 marks]
-m+ at m/7=136??
-C4H4O E.F.
-C8H8O2 M.F.

Reagents Flowchart [3? marks]
Dilute HCl(aq)


Reagents and isomers [5 marks]
3-methylcyclohexanone
NaBH4
3-methylbromohexanone
3-methylcyclohexene
4-methylcyclohexene

Unknown Aromatic Compound - observations [3 marks]
- Weakly acidic pH but no reaction with the weak sodium carbonate base => phenol.
- 2,4-DNPH ppt but absence of silver mirror with Tollens' => carbonyl, not an aldehyde so ketone.

Unknown Aromatic Compound - carbon NMR to suggest structure [3 marks]
- 6 carbon environments
- 4-hydroxyphenylethanone

Combined Techniques (last question) [6 marks]
2,2-dimethylpropyl propanoate
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Fox Corner
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Nice markscheme! I've added it into the unofficial markscheme list
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medhelp
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https://www.thestudentroom.co.uk/sho....php?t=4791330
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nat3e
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Not sure what question was that but this question was about diagram either 4 or 5 marks

Reducting agent: NaBH4
Isomers: 2-methylcyclohexene and 3-methylcyclohexene
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blazingriver
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4 Chriral carbons

C40h56+11h2->c40h78
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blazingriver
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Z isomer B

For reagents
Dilute HCl and water
NaBH4 and water
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nat3e
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The other question asked about diagram about CN

HCOH to H2C(OH)CN then it needs LiAlH4 to from H2C(OH)CH2NH2
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Tuffyandtab
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Beta carotene Q
C40H56 + 11H2 --> C40H78


Last question I got an ester - CH3CH2COOCH2C(CH3)3
Question before with carbon-13 NMR - phenol with ethanone joined together.

I'm pretty certain on these.
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Tuffyandtab
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(Original post by DoubleDoors)
Combined Techniques (last question) [6 marks]
2,2-dimethylpropyl ethanoate
I believe it was 2,2-dimethylpropyl propanoate
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DoubleDoors
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(Original post by Tuffyandtab)
I believe it was 2,2-dimethylpropyl propanoate
Ah yeah because of the CH3CH2. Thank god I still remember putting that!!
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blazingriver
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The one about benzene vs benzeanoic acid and phenol. Benzeanoic electron withdrawing. Phenol electron donating. Benzene is between the two etc
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URGENT Issue
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Predictions for A/A* grade boundaries?
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puusssss
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Multiple choice answers
1. B 2. D 3. C 4. B 5. D 6. C 7. A 8. C 9. C 10. D 11. C 12. A 13. A 14. C 15. A
probs all wrong tbf
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avz1512
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any predictions for grade boundaries?
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cuzwhynot
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(Original post by Tuffyandtab)
Beta carotene Q
C40H56 + 11H2 --> C40H78


Last question I got an ester - CH3CH2COOCH2C(CH3)3
Question before with carbon-13 NMR - phenol with ethanone joined together.

I'm pretty certain on these.

CH3CH2COOCH2C(CH3)3-
yep i got this too!
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Julz619
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hex-3-enol >>>>>> is the 1-ol required or can that be implied
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Julz619
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grade boundaries last year for new spec AS was 80% (56/70) for an A in paper 1 so grade boundary probz 80 for A, 89 for A* this year
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StA200
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(Original post by Julz619)
grade boundaries last year for new spec AS was 80% (56/70) for an A in paper 1 so grade boundary probz 80 for A, 89 for A* this year
Overall it was lower than that. 56 was on the depth paper which was straight forward
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Toffo132
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(Original post by DoubleDoors)
Can't really remember many of the questions now, so please contribute!

Fox Corner


MCQ Section [15 marks, 1 mark each]
1. Silver Nitrate
?. Z isomer was the one with Cl and F on the same side.
?. 5 chiral carbons


Section B [85 marks]

Name the alcohol/alkene [1 mark]
Hex-3-en-1-ol (ACCEPT 1-hydroxy hex-3-ene)

Define Stereoisomers [1 mark]
Molecules with same structural formula, different spatial arrangement.

Purifying the benzene based solid and assessing purity [6 mark]
-Filter under r.pressure
-Recrystallise (hot solvent and cool)
-Filter under r.pressure (cool solvent)
-Dry
-Melting point compare with known mp (data book/database)
% yield - ???

Unknown Aromatic Compound - molecular formula [2 marks]
-m+ at m/7=136??
-C4H4O E.F.
-C8H8O2 M.F.

Reagents Flowchart [3? marks]
Dilute HCl(aq)


Reagents and isomers [5 marks]
3-methylcyclohexanone
NaBH4
3-methylbromohexanone
3-methylcyclohexene
4-methylcyclohexene

Unknown Aromatic Compound - observations [3 marks]
- Weakly acidic pH but no reaction with the weak sodium carbonate base => phenol.
- 2,4-DNPH ppt but absence of silver mirror with Tollens' => carbonyl, not an aldehyde so ketone.

Unknown Aromatic Compound - carbon NMR to suggest structure [3 marks]
- 6 carbon environments
- 4-hydroxyphenylethanone

Combined Techniques (last question) [6 marks]
2,2-dimethylpropyl propanoate
Few more questions and my answers(if we disagreed on anything i'll bold it)
MCQ:
4 Chiral centres
atom 3 was trigonal planar
6.02x10^22 atoms
C2H4O
3 NMR peaks
C4H14
alicyclic and saturated

section B
Reagents Flowchart: H2O/Hcl, HCHO drawn in left box, H2/Ni down

1,6 hexandiamine and butandioc acid
two repeat units, biodegradable as ester bond hydrolysed

108cm^3
C40H56 + 11H2 -> C40H78

95 repeat units

71% yield, method for purifying organic solid

Butanol oxidised: to aldehyde and to Carb acid. butanol + [O] > Butanal + H2O, distill, cr2o7-/h+
butanol + 2[O] > Butanoic Acid + H2O, reflux, cr2o7-/h+
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Toffo132
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(Original post by Julz619)
grade boundaries last year for new spec AS was 80% (56/70) for an A in paper 1 so grade boundary probz 80 for A, 89 for A* this year
More content to not remember/apply correctly, more marks (so % of marks dropped will likely rise), I reckon for the two papers so far:

paper 1 (A*,A,B,C,D,E,U)
88,80,72,66,58,50,0

paper 2 (A*,A,B,C,D,E,U)
85,79,73,68,61,54,0

For paper 3, I reckon it'll drop to about:
(outta 70)
55,48,42,36,30,25,0

overall: 228,207,197, 170, 149, 129
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