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***OFFICIAL*** OCR AS CHEMISTRY F321 and F322

Discuss all problems etc. on this page!
F321 (Atoms, Bonds and Groups): Friday 23rd May 2014
F322 (Chains, Energy and Resources): Tuesday 3rd June 2014

PAST PAPERS (June 2013 expected to be uploaded in the next week of so):
http://www.ocr.org.uk/qualifications/as-a-level-gce-chemistry-a-h034-h434/

TIPS:
1. Do ALL the past papers, similar questions frequently reoccur.
2. Read the specification, make sure you know the content not just the textbook!
3. Learn all the definitions mentioned in the specification.
4. If your stuck ask your teacher or comment on here.

Notes for F321:
http://getrevising.co.uk/files/documents/chemistry_a_f321_notes/Chemistry.pdf

Notes for F322:
http://www.thestudentroom.co.uk/attachment.php?attachmentid=148502&d=1337182526

Anymore resources post them on this forum page.

Good luck!
Hi there,

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Hey, I'm abit stuck on the fissions, mechanisms and the radical stuff (e.g. in alkanes and the ozone). does anyone have a good resource TO HELP ME or can you explain it in detail?
Thanks for this :smile:
On an off note your the first blue gem I've seen :woo:
Good luck to you too :smile:
Reply 4
Original post by mrchemistry
Hey, I'm abit stuck on the fissions, mechanisms and the radical stuff (e.g. in alkanes and the ozone). does anyone have a good resource TO HELP ME or can you explain it in detail?

If your talking about alkanes then:
For example Chlorine with methane:
Overall equation: Cl2 +CH4 -> HCL +CH3CL
INITIATION
Chlorine undergoes homolytic fission under the presence of UV radiation at 300oC
PROPAGATION

1) Cl + CH4 -> CH3 + HCL A chlorine radical reacts with methane to produce a methyl radical and hydrochloric acid.
2) CH3 + CL2 -> CL + CH3CL ​The methyl radical created in propagation step 1, reacts with a chlorine molecule to produce a chlorine radical and CH3CL.
TERMINATION
Any left over radicals can be reacted together e.g
Cl + Cl -> Cl2
Ch3 + Cl-> Ch3cl
Ch3 + Ch3 - > C2H6

Ozone:
It looks at how a radical can react with an ozone molecule to break it down.
For example nitrogen oxide:
Overal equation: NO + O3 -> 2O2
Steps:
NO + O3 -> NO2 + O2 NO radical reacts with an ozone molecule to produce a NO2 radical and an oxygen molecule.
NO2 + O -> NO + O2 NO2 radical reacts with an oxygen atom to produce a NO radical and an oxygen molecule.

This process repeats as it produces a new NO radical every time.

Good video for revision of this:
https://www.youtube.com/watch?v=7k9UwilnhGw
Original post by bbadonde2
If your talking about alkanes then:
For example Chlorine with methane:
Overall equation: Cl2 +CH4 -> HCL +CH3CL
INITIATION
Chlorine undergoes homolytic fission under the presence of UV radiation at 300oC
PROPAGATION

1) Cl + CH4 -> CH3 + HCL A chlorine radical reacts with methane to produce a methyl radical and hydrochloric acid.
2) CH3 + CL2 -> CL + CH3CL ​The methyl radical created in propagation step 1, reacts with a chlorine molecule to produce a chlorine radical and CH3CL.
TERMINATION
Any left over radicals can be reacted together e.g
Cl + Cl -> Cl2
Ch3 + Cl-> Ch3cl
Ch3 + Ch3 - > C2H6

Ozone:
It looks at how a radical can react with an ozone molecule to break it down.
For example nitrogen oxide:
Overal equation: NO + O3 -> 2O2
Steps:
NO + O3 -> NO2 + O2 NO radical reacts with an ozone molecule to produce a NO2 radical and an oxygen molecule.
NO2 + O -> NO + O2 NO2 radical reacts with an oxygen atom to produce a NO radical and an oxygen molecule.

This process repeats as it produces a new NO radical every time.

Good video for revision of this:
https://www.youtube.com/watch?v=7k9UwilnhGw


Thanks! I was also wondering, when you get like 8 markers on mechanisms, do you have to draw the curly arrow model AND explain each step in detail?
Reply 6
Original post by mrchemistry
Thanks! I was also wondering, when you get like 8 markers on mechanisms, do you have to draw the curly arrow model AND explain each step in detail?

If we get mechanisms for radical substitutions they only expect you to know the equations for it not the curly arrow stuff. However, for electrophillic addition and nucleophillic substitution it will require you to draw the mechanisms with curly arrows and relevant dipoles. I would expect all or at least two of these types of reactions in this years paper.
I have the JUNE 2013 past paper if anyone's still looking for it
I also have the mark scheme if anyone wants that. I've attached the paper above. Good luck everyone! Im screwed for it anyway :smile:
Reply 8
Can you attach the mark scheme too please?
Reply 9
Original post by Arshi_chelsea
I have the JUNE 2013 past paper if anyone's still looking for it
I also have the mark scheme if anyone wants that. I've attached the paper above. Good luck everyone! Im screwed for it anyway :smile:

Hi please can you attach the mark scheme too?
Please attach the mark scheme, been looking for it for ages and cannot find it anywhere… GOod luck to everyone
Here is the Mark scheme for June 2013 - Sorry if it's late guys, I was going back home from the library

Also, Can anyone help me with bonding?
Do we all agree that it is by far the trickiest topic in f321 because of how wide it is and the confusion of the bond angles/lone pairs/ symettrical molecules? I just think that OCR will take advantage of this particular gap in people's knowledge and make sure they test this thoroughly - this year all exam boards seem to be set out to trip candidates up anyway, so I reckon this is what will be done in the exam tomorrow.
I mean in my WJEC biology BY1, They asked a question from The next unit that wasnt even on the spec. Anyway.
(edited 9 years ago)

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