Current Year 13 Thread Mark II (2014/15)

wat

I got one as the zwitterion of glutamic acid (m/z=129) and the other one was just two zwitterions bonded together (m/z=258).

*good differentiator

Oh that, I drew two cyclic structures for that, they had the correct masses I believe (so one was glutamic acid bonded to itself, the other a dipeptide bonded to itself). Hope that wasn't bull****.

129 was the mass of glutamic acid minus H20 so I figured it had to have a peptide in there (258 was the dipeptide minus water).

Unless I'm wrong the zwitterion should have the same mass as the molecular amino acid.

Oh **** lel you're right, got confused about what the zwitterion is. That's 2 marks lost. I just took water out and left the ends and HN+ and CO- and didn't bother joining them up. Then i did the dipeptide but didn't join the ends up again.

Awh No matter, sure you did fine on the rest, right?

No offense to OCR people, but 2-4 DNPH is quite easy to do? We covered it in AS Chemistry with CIE, as well as the reactions and products. Perhaps you've never seen it in a past paper before but as long as you know the structure of the compound it really comes down to common sense (within your knowledge of chemistry)

The question had a 2,4-DNP product but the question was actually NMR. I didn't even read it properly because of time constraints so I had no idea it was about 2,4-DNP until after the exam. It was purely a H NMR question.

What's this new @ thing? Didn't know about this

Is the 'Clearing' ad bothering anyone else? It seems to deliver a subliminal message, like I'll be needing it in August. Doesn't help calm my nerves :P

https://www.change.org/p/ocr-award-automatic-full-marks-on-the-question-s-about-2-4-dnp-in-the-f324-june-2015-exam-paper?recruiter=222577876&utm_source=share_petition&utm_medium=facebook&utm_campaign=share_page&utm_term=des-md-share_petition-custom_msg&fb_ref=Default

Lol, even worse than asking for low boundaries.

No offense to OCR people, but 2-4 DNPH is quite easy to do? We covered it in AS Chemistry with CIE, as well as the reactions and products. Perhaps you've never seen it in a past paper before but as long as you know the structure of the compound it really comes down to common sense (within your knowledge of chemistry)

I think it was the fact that it literally said as an "examiner's tip" in the textbook that it wouldn't come up. Also I know that for edexcel at least, we aren't taught what the hydrazine group is, so I wouldn't be able to draw it...