OCR chemistry F321 exam friday 13th jan 2012

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Reply 760

anuradha_d

Original post by 1212

This is what I got!!

Reply 761

Neuro Alex

Hi everyone, I've just signed up to this website after reading through many posts on this particular thread.

Like a lot of people on here I was very disappointed with both the paper, my performance in time management and how I responded to the questions in general. I am predicted A's in all science / maths AS papers this year, I'm not the brightest of the bright but I do work exceptionally hard consistently throughout the year and by exam time I will be able to recite the revision guide as was the case this time.

My take on the exam in general was that there were a lot of high level questions, although clearly asked, the large percentage of high difficulty questions far outweighed the calibre of previous exams. Exam pressure is likely to hinder logical thinking but I still think the questions were on average harder than the mock papers we had all done. I think it will be harder to distinguish between higher grade students, a small percentage will shine with exceptional scores but due to the nature of the questions a lot of students predicted A's may achieve similar scores to (on paper) lower level candidates which I believe devalues the importance of revision. I am sure OCR and other exam boards have some algorithm to work out the grade boundaries and I genuinely believe they will be low and perhaps around 40. I think some people who have commented on here have shown little empathy to the anxiety a lot of people are feeling at the moment.

Personally I found the Biology okay, I had a bit of a block on some maths questions but hope that I was quite full proof on most other questions and genuinely believed Chemistry would be the easiest! I messed up the CaO question, forgot dipole-dipole forces on ICl, didn't know the molecule shape, and made some other smaller mistakes. I shall be hoping for low grade boundaries and hope I didn't make many more mistakes than I already know about and hopefully a lucky one or 2 from questions I've dismissed.

I'm going to work even harder up until March and then I will be able to calculate exactly what I need to achieve in summer examinations with no intention of retaking.

Reply 762

AladdinSane94

Hi I have Friday's exam paper. Are we allowed to put it on here?

Reply 763

james20207

Original post by AladdinSane94

Hi I have Friday's exam paper. Are we allowed to put it on here?

Please do! :smile:

Reply 764

choccandy21

Original post by aladdinsane94

hi i have friday's exam paper. Are we allowed to put it on here?

yes please

Reply 765

beccck_

Someone scanned a copy of the paper, here's the link:
http://www.photoshop.com/users/AladdinSane42/albums/c3cdd98a74ea4ef9b7d7bb3a9387bb00
Will someone now be able to make an unofficial mark scheme?
(hope the link works :smile:

)

Reply 766

james1234190

For the question on the student being unsure of the reactivities, I put that it would be difficult to measure the rate of reaction of the two reactions, as the only product is that of the salt (solid) and it may be hard to distinguish the metal from the salt. Clutching at straws there, missed the point of the question but is the logic behind it perhaps slightly plausible?

Reply 767

ab12345

Original post by james1234190

I think that question was really asking for the fact that as you go down group 2 reactivity increases, and down group 7 it decreases...?
So the student might me unsure of reactivity.

Reply 768

james1234190

Yep, I know now that was what they were getting at, but do you think I might scrape a mark for that explanation?

Reply 769

mucgoo

No. The question was asking specifically about a comparison of "relative reactivity".

Reply 770

otrivine

Original post by mucgoo

No. The question was asking specifically about a comparison of "relative reactivity".

if you get between 38-43/44 marks is it chance is A ?

Reply 771

monkey101

Original post by mathslover1

there was a similar question on this in 2008; between HCl and CH4 here was the mark scheme says;

CH4:
van der Waals’ forces /
interactions based on instantaneous/temporary/transient interactions 􀀹
HCl:
(permanent) dipole – (permanent) dipole interactions 􀀹
intermolecular forces are stronger in HCl than in CH4 /
more energy required to break the intermolecular forces in HCl than in CH4 􀀹

http://www.freeexampapers.com/get_past_papers.php?l=Past_Papers%2FA+Level%2FChemistry%2FOCR%2F2008+Jan%2FL_A_Level_Chemistry_MS_Jan_08.pdf

I have got that wrong then! :frown:

I don't know how i am going to be able to do my other january exams, when i am so depressed about this one!

Reply 772

james1234190

Hey all, I have put together a rough draft for an unofficial mark scheme at http://www.thestudentroom.co.uk/showthread.php?t=1893679 . Please do take a look at it, it's a work in progress so any comments or criticism are more than welcome.

Reply 773

jcrusader

Would i get the marks for the bonding question if i put-

Ionic lattice and Covalent?

is this AS or gcse's

Original post by kdotshah

is this AS or gcse's

AS.

Reply 776

ab12345

Thank you for your recent e-mail in which you have commented on the January 2012 F321 AS Chemistry examination.

The topics tested in this examination cover a broad range of the F321 specification content, and the style and level of demand of the paper does not differ from that of past papers.

The paper is set at an appropriate standard for AS level and is designed to enable candidates of different abilities to demonstrate their knowledge of chemistry and also to apply that knowledge in a variety of chemical contexts. We are confident that this paper is appropriate and fair.

If you have not already done so you should discuss any concerns you have about this examination or your performance in the examination with your teacher.

OCR Complaints Team

<-----That's the reply someone from my school got from OCR

Reply 777

Jakez123

Can anyone assess my answer for the 6 marks question, it was the one about KBR, K and H20

I said

For K, it has strong attractive forces between K+ metal ions and delocalised electrons, therefore are hard to break.

KBR has a strong ionic lattice consisting of oppositely charged ions, due to no moving ions or electron it will take more energy to break unlike Metallic bonding.

Therefore KBR > K

Lastly H20 forms hydrogen bonds and vanderwaals forces, but to melt something all you have to do is break the inter-molecular forces therefore it has a low melting point therefore KBR > K > H20

Reply 778

Neuro Alex

Very similar to me and a lot of people Jake my guess is it would be at LEAST 4, but up to 6 depends if they wanted the "relative strengths" for a mark or 2 but I would take a bet and say that was a 5 without it.

Reply 779

Jakez123

Ok, last question before i call it a day, for the question on why the student was unsure about the reactivity i practically wrote:

As you go down group 7 Reactivity decreases and Reactivity increases down group 2 therefore the student would be unsure over the most reactive compound.

I take it my answer would score no marks because i did not mention The compounds?