OCR A Chemistry Paper 2 Unofficial Mark scheme

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Reply 20

Yeahwhat

Original post by TheAlphaParticle

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

I think there was. I am not entirely sure though!!

Reply 21

PeterCrabtree

Original post by TheAlphaParticle

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

There was, the first peak was RC-O

Reply 22

Ashleigh123456

Original post by Boss987

71% yield.
Did anyone get 95 repeat units?
Ester for hydrogen NMR. This includes 3 CH3.
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 Chiral carbons??
Acyl chloride + primary amine = amide MCQ
Alicyclic and saturated??

Help me finish the mark scheme!!!

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)

Reply 23

PeterCrabtree

Original post by mobrien2404

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

No the ring sure were alicyclic. It wanted to to work out that for every ring two carbons are lost so you have to consider that when working out the structure.

Reply 24

iamDev

Original post by Ashleigh123456

Did we need to state structure of M and N

Reply 25

Ashleigh123456

Original post by iamDev

Did we need to state structure of M and N

i think so yes

Reply 26

ellie.elephant

Im so mad in the butan-1-ol question I got it all fine but I accidentally put the equation to form a carboxylic acid as forming 2H20 :frown:

how many marks will I lose, just one?

Reply 27

iamDev

Original post by TheAlphaParticle

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

It was weakly acidic as ph 5. So it's carboxylic acid or phenol.not c acid because it didn't react with carbonate. Must be phenol

Reply 28

Theragingninja

Original post by Ashleigh123456

i think so yes

it only asked for structure L so no

Reply 29

dhr_jacobson

Got this for last question, not sure which one is correct though

Reply 30

PeterCrabtree

Original post by ellie.elephant

Im so mad in the butan-1-ol question I got it all fine but I accidentally put the equation to form a carboxylic acid as forming 2H20 :frown:

how many marks will I lose, just one?

One maximum!

Reply 31

Gaby123

Original post by TheAlphaParticle

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

The carbon in the C-O might have counted as one of the benzene environment peaks. I didn't identify phenol either in the exam though, just hindsight thoughts.

Reply 32

neuroKL

Anyone else get C40H44 + 11H2 --> C40H66 for the beta carotene?

(edited 6 years ago)

Reply 33

Yeahwhat

Original post by Ashleigh123456

i think so yes

U don't need to.

Reply 34

Gaby123

Original post by Gaby123

The carbon in the C-O might have counted as one of the benzene environment peaks. I didn't identify phenol either in the exam though, just hindsight thoughts.