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F321 January 13th 2011: OCR Chemistry A Exam

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Yeah, it was relatively easy. However, the answers you had to provide were all quite lengthy and time constraints made the exam harder than it should have been, i.e the displacement reaction halogen/halides question, whereas in past papers you simply filled out tables for example stating colour change, this time it being a 6 mark short essay question, completely ruined my time management. Otherwise the rest of the exam was easy and I should imagine the grade boundaries will be quite high for this paper.

So paul joseph ... what is HxA about and the mass of the (OH) part and why less hydrogen was produced alothough down he group it gets more reactive?

Reply 81

sofiakousar

Original post by CeeTay

did you manage to finish, does anyone know the worth of the final redox reaction q, and the question to put in the element on the last page as that is what i didn't manage to do ?

the redox was 2 marks and the one. i think it was 1 or 2. so its total of 3 or 4 marks on the last page.

Reply 82

KingofSpades

Original post by sofiakousar

the redox was 2 marks and the one. i think it was 1 or 2. so its total of 3 or 4 marks on the last page.

2 marks for balancing
2 for redox
1 for electron config
1 for GaF or sumit like that

Reply 83

Oink123

I put that Barium produced less Hydrogen gas because as you go down group 2, the hydroxides formed are more soluble. More Barium hydroxide is produced and therefore less hydrogen gas is given off.
In the OCR Chemistry book, it says:
'Ba(OH)2 is much more soluble in water than Mg(OH)2, with a greater OH- concentration. The resulting solution is more alkaline than a solution of Mg(OH)2.'

Reply 84

Tanina

Original post by fredmc

thats what i did for the electronegativity diagram, i just mucked up on the definition, by only putting "the ability of an atom to pull in surrounding electrons" or something like that, but i should of mentioned its in covalent bonds, though ive just checked google which seems to confuse me :s-smilie:

http://www.google.co.uk/search?sourceid=chrome&ie=UTF-8&q=define+electronegativity
would I have got any out of the two marks?

its been said on another thread, but thought i'd ask it here, what did people get for the conc. of hydroxide ions?
i got 0.01048 dm^3 mol^-1, as there were two moles of hydroxide ions out of the 250 cm^3 solution. I did (0.00131*2)/0.25 and got that answer :biggrin:

most likely got it wrong! :P

I got the same answer for the concentration of hydroxide ions and my chem teacher said it was right :/

Reply 85

Yinkx92

Original post by KingofSpades

6

what's the difference between this exam and "salters OCR"?

Salters is much more difficult, in the unit 2 paper you are given pre release material to read up before the exam. For salters there are two text books that need to be read for AS. The Core material and a book containing information about the story behind the content. Both you will be tested on in the exam.

(edited 13 years ago)

Reply 86

TougherThanYSZ

Fantastic. Grade boundaries are out and as I predicted earlier in this thread, for an A you only needed 44 marks.

Reply 87

patra

Original post by pauljoseph

Fantastic. Grade boundaries are out and as I predicted earlier in this thread, for an A you only needed 44 marks.

for the ocr you need 47 for an A :smile:

Reply 88

Hyperbole08

Original post by patra

for the ocr you need 47 for an A :smile:

OCR A is 44 for an A :smile:

http://www.ocr.org.uk/download/admin/ocr_56047_admin_unit_level_raw_mark.pdf

Reply 89

patra

Original post by Hyperbole08

OCR A is 44 for an A :smile:

http://www.ocr.org.uk/download/admin/ocr_56047_admin_unit_level_raw_mark.pdf

oooppps got it confused with economics! How do you feel about the grade boundary?

Reply 90

Hyperbole08

Original post by patra

oooppps got it confused with economics! How do you feel about the grade boundary?

I think its quite low - according to the way the work out A2 boundaries for 90% UMS.... 50 marks, should be 81 UMS , because the difference between an A and B is 6 marks and most A2 90% conversion points are calculated by adding the difference between a grade A and B, on top of a grade A to give 90% UMS. Lol sorry if I've confused you - Ive done this exam many times (Resits) so you would expect me to probably find it easier then most.