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

1. (Original post by Iamjos)
How did you work it out?
I must have confused the theoretical moles with the actual moles :-/
2. If I got f wrong, will I get ecf?
3. (Original post by bulkybros100)
i got 7.14 too!
For me =]
STEP 1: work out moles of starting substance
STEP2: multiply this value by 0.61
STEP 3: multiply that value by mr of A
4. (Original post by Mathematicus65)
100 ums - 55/60
a* - 50/60
a - 46/60
b - 42/60
That's too low for an A I think given how easy the paper was.
5. (Original post by k.russell)
Well I think it depends on the specific wording because if it says 'which COMPOUND is formed' then NH3+ is a lost mark bc it's an ion not a compound, however if I remember correctly, it just asked for the products? So if it's products then NH3+ is probs ok..
Fair enough, you have your reasoning and I have mine.

As far as I know, amines reacting with HCL doesn't produce ions, but there you go.
6. (Original post by MrZebraCookie)
But the book says that trans fats behave like saturated fats in the body idek
But you dont know if the alkene groups are cis or trans. thats why I think its the saturated fatty acid
7. What was the other organic product in the ethanoic anhydride question?
8. (Original post by Irmakozturk)
i got quartet for the last one
was the multiplet a sextet?
9. (Original post by Iamjos)
How did you work it out?
% yield = mol of A/mol of phenylamine *100

so mol of A = %yield /100 * mol of phenylamine

mol of phenylamine = 3.00/93 = 0.03225...

so moles of A = 0.03225* 0.61 = 0.019677...

So mass = mol*mr = 0.019677...*135 = 2.65645... = 2.66 to 3 sf
10. (Original post by sydneyl3igh)
What was the other organic product in the ethanoic anhydride question?
Ethanoic acid I think
11. They did 3/94=0.032
0.032/0.61=0.0528
0.0528*135=7.1
12. (Original post by sydneyl3igh)
What was the other organic product in the ethanoic anhydride question?
Ethanoic acid
13. When naming the type of condensation polymer would polyamide be sufficient or did you need to put nylon
14. Did anybody count 5 carbon environments on the NMR, there was a small little line next to the final peak. Would that signify a straight chain secondary alcohol?
15. (Original post by mil88)
Fair enough, you have your reasoning and I have mine.

As far as I know, amines reacting with HCL doesn't produce ions, but there you go.
Can we just let it go. It's just 1 mark. I know for sure I've dropped this mark. I hope I haven't lost more.
16. (Original post by Derek12353)
For me =]
STEP 1: work out moles of starting substance
STEP2: multiply this value by 0.61
STEP 3: multiply that value by mr of A
i got 2.66 though
17. (Original post by Derek12353)
really? the NMR question from last year would have finished me !
I am quite good and that, on the other hand, I tend to stumble at word questions at topics like triglyceride, degradable stuff, chromatography. There are quite a lot of them this time, and no nmr for me to back up my marks i am really frightened now
18. (Original post by Iamjos)
But you dont know if the alkene groups are cis or trans. thats why I think its the saturated fatty acid
Did the question specify they were naturally occurring? The trans isomers don't occur in nature
19. For the poly(lactic acid) one I put it is biodegradable and breaks down into co2 and h2o as that is the definition of biodegradable in the book, is this right or is it hydrolysed into the monomers?
20. (Original post by Iamjos)
I got something similar like 7.14g! How did you guys work it out?
I did that at first and then realised it was wrong. When I worked out the moles I put this as the actual moles instead of theoretical moles so the division was just the wrong way round, but you should get marks for calculating the moles correctly and stuff.

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