You are Here: Home

# OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012 Tweet

Chemistry exam discussion - share revision tips in preparation for GCSE, A Level and other chemistry exams and discuss how they went afterwards.

Announcements Posted on
1. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
does anybody have the mark scheme for http://www.a-levelchemistry.co.uk/OC...resources.html

the transition elements hw part 1 and 2? and the link for the test paper and the markscheme? thanks.
2. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
Has anyone done june 2010 paper and question 7b?
3. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
I found the concentration of h202 in 250cm3 but what do you do after that?
4. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by Dan12)
Has anyone done june 2010 paper and question 7b?
Sorry, when I quoted you earlier I thought this was a maths thread and you were talking about a maths question. Only just scrolled up
5. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by Dan12)
I found the concentration of h202 in 250cm3 but what do you do after that?
Don't find the conc in 250cm^3, go a step back and use the mass of H2O2 you found in 250cm^3 and then divide this by 25cm^3 to get the concentration of the undiluted solution.

The same mass of peroxide in 250cm^3 is in the original 25cm^3 since the student only added water.

I got an answer of 15.9gdm^-3.
6. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
I've found this question dunno which year it is tho so dont have the mark scheme..wondered if anyone has!? if not please mention what you put for 7 marks

The complex [CoCl2(H2NCH2CH2NH2)2] shows 2 types of isiomerism. Use this to explain what you understand by the term stereoisomerism. Include diagrams to show both types of isomers...
It was worth 7 marks
7. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by arvin_infinity)
I've found this question dunno which year it is tho so dont have the mark scheme..wondered if anyone has!? if not please mention what you put for 7 marks

The complex [CoCl2(H2NCH2CH2NH2)2] shows 2 types of isiomerism. Use this to explain what you understand by the term stereoisomerism. Include diagrams to show both types of isomers...
It was worth 7 marks
It was Jan 05 Transition Elements - paper and marking scheme attached
Attached Files
8. 2815-06_2005_jan_w.pdf (131.2 KB, 69 views)
9. 2815-06_2005_jan_p.pdf (111.8 KB, 71 views)
10. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by arvin_infinity)
I've found this question dunno which year it is tho so dont have the mark scheme..wondered if anyone has!? if not please mention what you put for 7 marks

The complex [CoCl2(H2NCH2CH2NH2)2] shows 2 types of isiomerism. Use this to explain what you understand by the term stereoisomerism. Include diagrams to show both types of isomers...
It was worth 7 marks
This would be my idea:
-Define stereoisomerism
-State the two types
-Draw diagrams of each (2-4 marks)
11. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by arvin_infinity)
I've found this question dunno which year it is tho so dont have the mark scheme..wondered if anyone has!? if not please mention what you put for 7 marks

The complex [CoCl2(H2NCH2CH2NH2)2] shows 2 types of isiomerism. Use this to explain what you understand by the term stereoisomerism. Include diagrams to show both types of isomers...
It was worth 7 marks
Oh I've seen/done this question. I don't know which paper it is either as I got it as part of a revision pack from my teacher. I have the mark scheme though:
One mark for the definiton of stereoisomer
Two marks for drawing cis and trans isomers
Two marks for drawing both optical isomers (must be mirror images)
[all diagrams to show 3D arrangement]
One mark for saying 'Enantiomers/non superimposable mirror images'
And one mark for saying 'rotate plane polarised light in opposite direction by same number of degrees'
I still don't really understand the last point, can anyone shed some light on this?
12. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by Cath-ay)
Oh I've seen/done this question. I don't know which paper it is either as I got it as part of a revision pack from my teacher. I have the mark scheme though:
One mark for the definiton of stereoisomer
Two marks for drawing cis and trans isomers
Two marks for drawing both optical isomers (must be mirror images)
[all diagrams to show 3D arrangement]
One mark for saying 'Enantiomers/non superimposable mirror images'
And one mark for saying 'rotate plane polarised light in opposite direction by same number of degrees'
I still don't really understand the last point, can anyone shed some light on this?
Yh the MS is up there! scroll up!
So As for last point! basically imagine you draw two enantiomers
then you shone light through a solution containing each of those enantiomers

for one of those solution: the enantiomer rotate the plane polarised light in clockwise direction

other enantiomer rotate it in anti-clockwise direaction

if you had both same amount (same volume?) then there will be no effect on the plane polarised light!

MS reads:"same number of degree" which I guess is referring to clockwise/anti .. (quote me if am wrong)

Couldn't figure out how we got cis/trans from a octahedral structure????
13. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by LifeIsGood)
This would be my idea:
-Define stereoisomerism
-State the two types
-Draw diagrams of each (2-4 marks)
yh you wouldn't get all the marks! not that I would :P

(Original post by clownfish)
It was Jan 05 Transition Elements - paper and marking scheme attached
Ok you officially own the google! it took you 2 mins to find it!!! impressed!
14. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by arvin_infinity)
Ok you officially own the google! it took you 2 mins to find it!!! impressed!
15. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by Tyles)
does anybody have the mark scheme for http://www.a-levelchemistry.co.uk/OC...resources.html

the transition elements hw part 1 and 2? and the link for the test paper and the markscheme? thanks.
These were the files that were uploaded to the website before some of the links became broken on transition metals, they probably aren't identical to the ones uploaded now with missing links but I suspect they're very similar
Attached Files
16. Transition Metals hw ms.rtf (286.9 KB, 68 views)
17. Transition Metals hw.rtf (685.0 KB, 742 views)
18. Transition Metals test.rtf (436.8 KB, 426 views)
19. Transition Metals test ms.rtf (77.6 KB, 40 views)
20. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
Sorry for the double post but I also have made some booklets for the 3 main topics in the exam. However they may be a bit broad so if anyone wants me to make a booklet that is more specific to a certain topic then feel free to ask
Attached Files
21. Energy.rtf (416.7 KB, 505 views)
22. Energy Scheme.rtf (179.1 KB, 47 views)
23. Rates, Equilibrium and pH.rtf (550.2 KB, 354 views)
24. Rates, Equilibrium and pH Scheme.rtf (325.2 KB, 68 views)
25. Transition Elements.rtf (444.3 KB, 423 views)
26. Transition Elements Scheme.rtf (331.4 KB, 66 views)
27. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by arvin_infinity)
Yh the MS is up there! scroll up!
So As for last point! basically imagine you draw two enantiomers
then you shone light through a solution containing each of those enantiomers

for one of those solution: the enantiomer rotate the plane polarised light in clockwise direction

other enantiomer rotate it in anti-clockwise direaction

if you had both same amount (same volume?) then there will be no effect on the plane polarised light!

MS reads:"same number of degree" which I guess is referring to clockwise/anti .. (quote me if am wrong)

Couldn't figure out how we got cis/trans from a octahedral structure????
Ahh yeah, she got to it first (I'm on my phone and had to dig out my copy lol)

Hmmm I kinda see what you mean! So 'same number of degrees' must refer to the fact that they are mirror images... Thank you

For cis trans, two of the ligands are bidentate, so you kinda have to put aside knowing that the structure is octahedral and treat each ligand as if the structure was square planar. I.e. one isomer has the Cl opposite each other, as with the ethane-1,2-diamine, and the other isomer, Cl's next to each other and ethane-1,2-diamine adjacent. Hopefully this clears it up a bit?!?
28. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by Cath-ay)
Ahh yeah, she got to it first (I'm on my phone and had to dig out my copy lol)

Hmmm I kinda see what you mean! So 'same number of degrees' must refer to the fact that they are mirror images... Thank you

For cis trans, two of the ligands are bidentate, so you kinda have to put aside knowing that the structure is octahedral and treat each ligand as if the structure was square planar. I.e. one isomer has the Cl opposite each other, as with the ethane-1,2-diamine, and the other isomer, Cl's next to each other and ethane-1,2-diamine adjacent. Hopefully this clears it up a bit?!?
Haha..yh better be quick next time :P
Well, I am glad I saw this question cuz I was gonna go to the exam room thinking cis/trans is only possible of tetrahedral and suqare planar
29. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
How's everyone revising for this? Death by past paper? Seems to be the best way with so much of the exam based on calculations
30. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by Patchey1000)
How's everyone revising for this? Death by past paper? Seems to be the best way with so much of the exam based on calculations
I thought I'd finally got this paper nailed. I've worked really hard on it with my teachers to make sure I knew what I was doing. And then I just did a past paper, not sure which, and suddenly I can't do half of it.

I hate EEE so much :P
31. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
(Original post by pcorbett94)
I thought I'd finally got this paper nailed. I've worked really hard on it with my teachers to make sure I knew what I was doing. And then I just did a past paper, not sure which, and suddenly I can't do half of it.

I hate EEE so much :P
Probably the June '11 paper
32. Re: OCR Chemistry A F325 Equilibria, Energetics and Elements Wed 13 June 2012
Does anyone have the F325 January 2012 paper and mark scheme? It would be greatly appreciated
Useful resources

## Articles:

Study Help rules and posting guidelinesStudy Help Member of the Month nominations

## Groups associated with this forum:

View associated groups