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

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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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    Nice markscheme! I've added it into the unofficial markscheme list
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    https://www.thestudentroom.co.uk/sho....php?t=4791330
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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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    4 Chriral carbons

    C40h56+11h2->c40h78
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    Z isomer B

    For reagents
    Dilute HCl and water
    NaBH4 and water
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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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    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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    (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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    (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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    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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    Predictions for A/A* grade boundaries?
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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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    any predictions for grade boundaries?
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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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    hex-3-enol >>>>>> is the 1-ol required or can that be implied
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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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    (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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    (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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    (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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