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OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD

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Reply 1940

adnan_ja01

for the equation of the reduction of the aldehyde to alcohol, would putting OH- as a second product be fine?

Reply 1941

gonecrazy

so is it ethanoic acid or propanoic acid?

Reply 1942

Rust Cohle

Original post by KB_97

The unofficial make scheme Google document is a hot mess. I'm gonna put what I got the last structures on here. If you got the same as me thumbs up if not say what you got and we'll see who agrees/disagrees

New unofficial mark scheme document

Only selected users can edit, everybody can comment.

https://goo.gl/gEi388

(edited 7 years ago)

Reply 1943

ali_t9001

Original post by lanah_

Is there an unofficial mark scheme?

https://titanpad.com/n3swQKWGYk

Reply 1944

Spwoosh

100% sure the NMR thing was doublet doublet quartet

Reply 1945

FluffyCommie

Original post by adnan_ja01

for the equation of the reduction of the aldehyde to alcohol, would putting OH- as a second product be fine?

Pretty sure the only acceptable form would be:

Aldehyde + 2[o] --> alcohol

Reply 1946

jamesgates1

Why did the secondary alcohol and ketone have a ch3 group off it? Why couldn't it be a straight chain?

Reply 1947

Michaelj99

Original post by jadder1224

did anyone get these ?

Does it have to have the methyl?! I just did it as straight pentanone :/

Reply 1948

President J

Original post by FluffyCommie

Pretty sure the only acceptable form would be:

Aldehyde + 2[o] --> alcohol

You mean 1 O right?

Reply 1949

FluffyCommie

Original post by gonecrazy

so is it ethanoic acid or propanoic acid?

it's definitely propanoic acid

Reply 1950

sakuraton

Original post by CharleaM

I got the Mr as 74 hence proanoic acid

Yeah, everyone else says 74,
I somehow got the number '60' as Mr which is a Mr for ethanoic acid funny enough so I thought I leave the answer there.
Yeah, you all probably right, Mr is 74

Reply 1951

marioman

Original post by A Slice of Pi

Did you also state the number of possible isomers (2)? They wanted to see the actual number of possibilities in the Jun15 paper.

Only because in June 2015 they specifically talked about 25% of the dose being effective (hence four optical isomers).

Reply 1952

Michaelj99

Original post by jamesgates1

Why did the secondary alcohol and ketone have a ch3 group off it? Why couldn't it be a straight chain?

thats what I did im so confused, it didn't say it was branched or anything either

Reply 1953

cr7alwayz

What I remember (there may be mistakes)

octadec-9,12-enoic acid because it has two trans isomers? which increases level of bad cholesterol.

Cis-trans isomerism requires different groups attached to each carbon in c=c bond.

Alcohol and amide.functional groups

condensation polymer was polyamide and used as fibres in clothing

Measure Rf values and compare with known Rf values. 2 spots instead of 3 because compounds may not have separated fully

Polylactic acid could breakdown because ester linkages could be hydrolyses and the stitches could be dissolved because lactic acid could form hydrogen bonds with water using its OH groups.

Diester made of six carbons and two ester bonds (skeletal formula)
Percentage yield mass = 2.66g

formula for peak A was just molecular formula with positive charge
peak B was CH3CH2NH2 (or something like that) and positive charge

work out mr of Compound H Mr - 74.
Compound H: CH3CH2COOH
For Compound J: (CH3)3CH2OH