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

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Thought it was pretty decent no nasty nmrs I put the only saturated fat as the heart disease on because they were all naturally occurring it said and trans fats arn't naturally occurring meaning the two with double bonds are unsaturated and therefore must have been the saturated one right ?


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Original post by mattyk5
i put the c=o on the 2nd carbon


Don think it could have been a straight line coz there was 5 carbons but only 4 carbon environments so I did 4 in a row then a methyl group on end and Ketone on 2nd carbon


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Original post by TSR121
Guys for the ketone on the last question was it 5 carbons in a row then the c=o on the middle carbon ?


That would give 3 carbon environments. The spectra showed 4 environments. I got that it was a ketone but not the same structure as you.
Original post by Hollyht
Don think it could have been a straight line coz there was 5 carbons but only 4 carbon environments so I did 4 in a row then a methyl group on end and Ketone on 2nd carbon


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Methyl group on the end carbon is the same as a 5 carbon straight chain. Did you mean methyl on the second to last carbon?
CH3CHOHCH(CH3)2 is the answer, i believe
Not sure it was as easy as January 2013 but definitely one of the easiest they have set. Fingers crossed 60/60 for me, suspect I may not have written enough on the stitching question to get all 3 marks though.
Original post by grannyG
CH3CHOHCH(CH3)2 is the answer, i believe


Damn it! i dont think i related my structure to the 13C NMR
[QUOTE="maisym00;65764987"]
Original post by anndz3007


Since when has saturated fat been good for you ahha, oh well it's done now


Sorry i was thinking cis in my head, well i may mess it up then, there was 17 c in sat.. acid and 15 C in the other 2 right, i think your answer may be right then
That was a fairly pleasant exam, just the three marker on PLA had me thinking. 2.66g for the yield question anyone? And molar mass of the carboxylic acid was 74, so I presumed it was C2H5COOH
Original post by rory58824
That was a fairly pleasant exam, just the three marker on PLA had me thinking. 2.66g for the yield question anyone? And molar mass of the carboxylic acid was 74, so I presumed it was C2H5COOH

What question about PLA was that?? And i got the same as you, ketone was like 4 straight C with a methyl group right ?
Original post by rory58824
That was a fairly pleasant exam, just the three marker on PLA had me thinking. 2.66g for the yield question anyone? And molar mass of the carboxylic acid was 74, so I presumed it was C2H5COOH


yeah i got that for the yield, and also got 74. I think i may have messed up on the structure of the ketone and then because of that the structure of the ester
Original post by rory58824
That was a fairly pleasant exam, just the three marker on PLA had me thinking. 2.66g for the yield question anyone? And molar mass of the carboxylic acid was 74, so I presumed it was C2H5COOH


ohhh why on earth did i get 2.61g nooooo :frown:((((((
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5824
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Do you think you'd get error carried forward for the CNMR boxes?
Original post by anndz3007
What question about PLA was that?? And i got the same as you, ketone was like 4 straight C with a methyl group right ?


Something to do with why it dissolves, I began talking about blood but I think that's wrong. The ketone was 4 straight carbons with a methyl group in there as well if I can remember
Original post by 5824
Do you think you'd get error carried forward for the CNMR boxes?


hopefully...
what was that thing for lactic acid in bacteria/by chemical synthesis? i said something about getting a pure product rather than a mixture of products...
[QUOTE="anndz3007;65765199"]
Original post by maisym00


Sorry i was thinking cis in my head, well i may mess it up then, there was 17 c in sat.. acid and 15 C in the other 2 right, i think your answer may be right then


Don't worry about it, it was only 1 mark 😀
Original post by rory58824
Something to do with why it dissolves, I began talking about blood but I think that's wrong. The ketone was 4 straight carbons with a methyl group in there as well if I can remember


Dissolves because it can make hydrogen bonds with water surely? due to -OH group?
Original post by 5824
Do you think you'd get error carried forward for the CNMR boxes?


Yeah it will be
3 for finding H
1 for structure of H
1 for F
1 for G

and then 1 for what you got for your H and what you got for your F to get the structure of I
I got 2.61 too! I think we used 60% instead of 61%, hopefully we'll get a couple marks though

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