Wjec ch4 2016

Can someone remember what the questions for question 4 were (apart from the NMR and mass spec bits)

Something about explaining NMR and IR spectra?
What the X axis is - answer was "retention time"
Finding out percentage volume of A - answer I believe was 20%
And something about the difference in what information you can find from thin layer chromatography and gas chromotography

Not sure if I've missed anything out

Na it gives you methyl bezene

http://www.chemguide.co.uk/mechanisms/elsub/fcalkyl.html

I really was unsure for the isomers at the start too because they all had to have a double carbon bond since they all declourised bromine, but i couldn't get the Hydrogens to match the orginal compound (if you were supposed to that). Anyone remember what they did?

I remember the isomers i did were ketones with double bonds.

What did you guys put for the question which asked about optical isomers and why it gave a certain figure (30 something)? Sorry this is described really badly!

Did you say that it formed a racemic mixture or not?

I drew one 1-ene isomer, and the 2-ene isomer that can also form displays E-Z isomerism. So one 1-ene isomer and the E and Z forms of the 2-ene isomer, making 3 in total. Not sure if that was the right answer, but it was the only one I could make that worked.

What did you guys put for the question which asked about optical isomers and why it gave a certain figure (30 something)? Sorry this is described really badly!

What about the solubility question?

There was a question with a phenylamine attached to an methyl group and then an OH. What happens when you react it with ethanoyl chloride. do you form an ester on one end and an N substituted amide on the other side?

I want to take a stab in the dark and say grade boundaries will be around 59 for an A, 53 for a B, 47 for a C and so on.
I think a lot of people didnt just find the questions difficult but also the way the exam was actually presented, it was nothing like I'd ever experienced before! I think I got full marks on Q1 because the questions were straight forward and actually on the spec. I couldn't get my head around the concepts in Q2. I didnt say Phenol wasn't acidic enough to react with sodium carbonate, and I also conpletely forgot about amino acids being zwitterions so I struggled on that as well. Q3 was incredibly difficult, but I think the majority of the country thought the same so this will be the question that brings the grade boundaries down. I made a silly mistake in Q4 and my answers about NMR/IR and GC/TLC are hit and miss. Q5 was good but I didnt understand why it said 'describe the mechanism' so I just drew it. I wasn't too sure what reflux meant so I just put boiling the liquid to a vapour and cooling to condense. Then the how science works question was dodgy, those answers are always hit and miss. Poor exam.