Competition - post a photo you've taken of nature >>

OCR A Chemistry Paper 2 Unofficial Mark scheme

71% yield.
Did anyone get 95 repeat units?
Ester for hydrogen NMR. This includes 3 CH3.
At the end L was a Ester: CH3CH2COOCH2C(CH3)2CH3
M was a carboxylic acid: CH3CH2COOH
N was an alcohol : HOCH2C(CH3)2CH3 (Ashleigh)
recrystallisation for the method.
Phenol with ethanone joined together. for C NMR.
https://www.thestudentroom.co.uk/attachment.php?attachmentid=665762&d=1497870262
Butan-1-ol + 2O] --> Butanoic acid and Water, using acidified potassium dichromate and under reflux
Butan-1-ol + [O] --> Butanal and water, using acidified potassium dichromate and distillation technique (AnnaRainbows)
Diol more soluble as it has two hydroxyl groups.
Alcohol forms h bonds with water so soluble.
https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=imgres&cd=&cad=rja&uact=8&ved=0ahUKEwiYpraK5snUAhXIRhQKHRq4ApsQjRwIBw&url=https%3A%2F%2Fsites.google.com%2Fsite%2Fchemistryolp%2Fproperties-of-alcohols&psig=AFQjCNE3IJAvXsyhyEHRkFttGAEllLCWZg&ust=1497957876618458
Beta carotene Q
C40H56 + 11H2 --> C40H78 (TuffyandTab)

MCQ
BDCBDCACCBCAACB (tamoni4)
AgNo3
C7H14 - molecular formula
Addition reaction (economy)
Trigonal planar - Atom no. 3
3 peaks for NMR in MCQ
3 or 4 Chiral carbons??
Acyl chloride + primary amine = amide MCQ
Alicyclic and saturated??

Good Paper!!!

(edited 6 years ago)

Scroll to see replies

Reply 1

blazingriver

Original post by Boss987

71% yield.
Did anyone get 95 repeat units?
Ester for hydrogen NMR. This includes 3 CH3.
recrystallisation for the method.
Ketone with benzene for C NMR.

MCQ
3 peaks for NMR in MCQ
3 Chiral carbons??
Acyl chloride + primary amine = amide MCQ

Help me finish the mark scheme!!!

1st question AgNO3, another multiple choice is C6H14 maybe it was c7

Reply 2

medhelp

Original post by Boss987

i got 4 chiral centres but im **** so im probably wrong

other questions i vaguely remember

butan-1-ol
the oxidation well it was distil to aldehye and reflux to COOH wasn't it? both with K2Cr2O7/H+

that recrystallisation was purity of benzoic acid after substituted with no2 + % yield

MCQS:
some bond angle ****

(edited 6 years ago)

Reply 3

URGENT Issue

Original post by Boss987

I got a ketone and phenol?
And 4 chiral centres

Reply 4

tamoni4

My MCQ answers were: BDCBDCACCBCAACB
Formula of unsaturated beta carotine was C40H56
Nylon 6,6 had 95 repeat units
For the first NMR question I had a phenylketone (C8H8O2)

(edited 6 years ago)

Reply 5

AnnaRainbows

Pray for error carried forward D: I definitely didn't get the right compound for the last NMR question my dumbass put amino acid rip

Reply 6

RainBear

How many marks will I lose for putting h+ in the oxidation equation instead of H2O? (I put H2O and then crossed it out)

Reply 7

Theragingninja

Hmmm for repeat units i got 140
C40H22
Phenol Ketone
Bond angle atom C
Branching - less points of surface contact hence weaker London forces
Yield = 73.56% (something along those lines)
Combined techniques last question was an ester

4 Chiral carbons
3 peaks for MCQ

Reply 8

Tuffyandtab

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.

Reply 9

Tuffyandtab

Beta carotene Q
C40H56 + 11H2 --> C40H78

Reply 10

avz1512

Original post by Boss987

71% yield.
Did anyone get 95 repeat units?
Ester for hydrogen NMR. This includes 3 CH3.
recrystallisation for the method.
Ketone and phenol group with benzene for C NMR.
https://www.thestudentroom.co.uk/attachment.php?attachmentid=665762&d=1497870262
Butan-1-ol + 2O] --> Butanoic acid and Water, using acidified potassium dichromate and under reflux
Butan-1-ol + [O] --> Butanal and water, using acidified potassium dichromate and distillation technique (AnnaRainbows)
Diol more soluble as it has two hydroxyl groups.
Alcohol forms h bonds with water so soluble.
https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=imgres&cd=&cad=rja&uact=8&ved=0ahUKEwiYpraK5snUAhXIRhQKHRq4ApsQjRwIBw&url=https%3A%2F%2Fsites.google.com%2Fsite%2Fchemistryolp%2Fproperties-of-alcohols&psig=AFQjCNE3IJAvXsyhyEHRkFttGAEllLCWZg&ust=1497957876618458

MCQ
BDCBDCACCBCAACB (tamoni4)
AgNo3
C7H14 - molecular formula
Addition reaction (economy)
Trigonal planar - Atom no. 3
3 peaks for NMR in MCQ
3 Chiral carbons??
Acyl chloride + primary amine = amide MCQ

Help me finish the mark scheme!!!

yep got 95 repeat units mr was something like 226 if you remember . what did yoou get for the beta carotene question, that was one i was unsure of

Reply 11

Theragingninja

Original post by Tuffyandtab

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.

I agree!

Reply 12

avz1512

Original post by blazingriver

1st question AgNO3, another multiple choice is C6H14 maybe it was c7

it was c7h14 which was choice C i think

Reply 13

tamoni4

For the last NMR question, I've got a
2,2-dimethylpropyl ethanoate

Reply 14

tamoni4

Original post by mobrien2404

In the beta carotene question it said it had 2 rings, was that referring to benzene rings?

No, they would have said aromatic rings if it was benzene.

Reply 15

AnnaRainbows

Why is it AgNO3 to measure the rate of activity/reaction? I put KCl because to see which one reacts fastest you need a displacement reaction? :frown:

Cl displaces both iodine and bromine and then you can look at the speed... oh gosh

Reply 16

TheAlphaParticle

Original post by Tuffyandtab

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.

but there was no C-O bond in the CNMR diagram, so how could it be phenol??

Reply 17

AnnaRainbows

Original post by mobrien2404

In the beta carotene question it said it had 2 rings, was that referring to benzene rings?

Nope it could have also meant alicyclic rings not aromatic

Reply 18

Yeahwhat

Original post by AnnaRainbows

Why is it AgNO3 to measure the rate of activity/reaction? I put KCl because to see which one reacts fastest you need a displacement reaction? :frown:

Cl displaces both iodine and bromine and then you can look at the speed... oh gosh

To see which one forms the precipitate first. Ag+(aq) + X-(aq) -------> AgX(s)

Reply 19

Ashleigh123456

At the end L was a Ester: CH3CH2COOCH2C(CH3)2CH3
M was a carboxylic acid: CH3CH2COOH
N was an alcohol : HOCH2C(CH3)2CH3

(although i'm pretty sure you could've had the groups the other way around too)