Equilibria, Energetics and Elements (F325) - June 2011 Exam.

I'm probably being dumb here, but why does K+ have a larger ionic radius than Ca2+. They would have the same number of electrons wouldn't they? 18...

i thought this cus i forgot completely about AS chemistry
same electrons, yes, but Ca2+ has more protons than K+ so theres a higher proton:electron ratio, so pulls the electrons in tighter, making the radius smaller :smile:

(edited 12 years ago)

Reply 581

INeedToRevise

8

Original post by wilsea05

i thought this cus i forgot completely about AS chemistry
same electrons, yes, but Ca2+ has more protons have K+ so theres a higher proton:electron ratio, so pulls the electrons in tighter, making the radius smaller :smile:

That makes a lot of sense. Thanks. :biggrin:

Reply 582

samzurai

i learned this whole spec in 2 weeks! took the jan 2011 mock paper and got 70/100 not bad

need to work on the stretch and challenge parts and hopefully i shall destroy paper (Y)

Reply 583

samzurai

i hate entropy can someone explain entropy and free energy/ spontaneous relationships??

thanks

Reply 584

tallysingh

Original post by INeedToRevise

I've been told to learn the equations!

Yeah you do have to learn them I just did a few questions, and you MUST know them, I dont think many students will fall in this trap.

Reply 585

CoventryCity

Hey does anybody have past papers for this exam, I have the specimen and the 2010 paper was just wondering if anybody could link me to the others.
Also I have 85/90 UMS in Rings, Polymers and analysis and I scored a raw mark of 37/40 for my ISA so I was just wondering what UMS/raw mark I would need in this exam to achieve an A*. An A* is 90% UMS in your A2 exams I believe?

Reply 586

sportycricketer

Original post by CoventryCity

Hey does anybody have past papers for this exam, I have the specimen and the 2010 paper was just wondering if anybody could link me to the others.
Also I have 85/90 UMS in Rings, Polymers and analysis and I scored a raw mark of 37/40 for my ISA so I was just wondering what UMS/raw mark I would need in this exam to achieve an A*. An A* is 90% UMS in your A2 exams I believe?

131/150 for the A*!

Reply 587

CoventryCity

Original post by samzurai

i hate entropy can someone explain entropy and free energy/ spontaneous relationships??

thanks

Entropy is a measure of disorder/randomness in a system.
Solid->Liquid->Gas
Entropy increases through each state.
The more molecules there are the higher entropy is.

Delta S = Sum Entropy of products - Sum Entropy of reactants
So if Entropy increases Delta S = +ve
If entropy decreases Delta S = -ve

Gibbs free energy
Delta G = Delta H - T x Delta S
Where T is in Kelvin
If Delta G < 0 the reaction is spontaneous
Delta G > 0 the reaction is not spontaneous
If it asks you to work out the minimum temp a reaction ca take place at then sub Delta G = 0 and rearrange for T

I believe that is right somebody correct me if I am wrong or missed something out

Reply 588

CoventryCity

Original post by sportycricketer

131/150 for the A*!

Thanks

Any idea what raw mark that is? 75-80 or more?

Reply 589

grey's

how do you guys work out how to draw impurities?

Reply 590

mauvetard

ANY KIND GORGEOUS SOUL OUT THERE PLEASANT ENOUGH TO SPARE ME A FEW MINUTES BY POSTING THE JAN 2011 PAPER ON THIS THREAD?. (hope this caught your eyes, but seriously I desperately need an A) :smile:

X

Reply 591

Salliana23

8

Original post by mauvetard

ANY KIND GORGEOUS SOUL OUT THERE PLEASANT ENOUGH TO SPARE ME A FEW MINUTES BY POSTING THE JAN 2011 PAPER ON THIS THREAD?. (hope this caught your eyes, but seriously I desperately need an A) :smile:

X

Someone posted it on the 1st/2nd page of this thread :smile:

Edit - Ecstacy posted a link to it on the 1st page - it's the post where there are also links to the June 2010 paper.

(edited 12 years ago)

Reply 592

mauvetard

Original post by georgianna

do you think we will need to know the colour of transition metals in different oxidation states?

I totally second this. In my ocr textbook, there is this horrific table showing the colours of the different compounds at different oxidation states. Do we really need to know all the specific colours for all transiton metals?v :frown:

Reply 593

mauvetard

Original post by Salliana23

Someone posted it on the 1st/2nd page of this thread :smile:

Edit - Ecstacy posted a link to it on the 1st page - it's the post where there are also links to the June 2010 paper.

Would the jan 2011 paper be the last two, the ones thta come up in word document? :smile:

Reply 594

Salliana23

8

Original post by mauvetard

Would the jan 2011 paper be the last two, the ones thta come up in word document? :smile:

No I think that they are just past paper questions but that is the post that I mean :smile:

It's the link that Ecstacy edited into the post - I've copied and pasted it here http://www.thestudentroom.co.uk/showpost.php?p=30708951&postcount=6

Reply 595

SmartFool

Has anyone got the exam CD uploaded onto their computer anywhere if so, could you possibly do a copy and paste of the answers? i desperately need the answers to the practice questions! Ive just looked to the back of my OCR text book and the CD has broken in half, cant believe i didn't notice until now! :frown:

(edited 12 years ago)

Reply 596

apo1324

11

Could someone please tell me where 34 has come from in the answer to 7b of the June 2010 paper. :frown:

http://www.ocr.org.uk/download/pp_10_jun/ocr_57551_pp_10_jun_gce_f325.pdf

Thanks.

Reply 597

sportycricketer

Original post by SmartFool

Has anyone got the exam CD uploaded onto their computer anywhere if so, could you possibly do a copy and paste of the answers? i desperately need the answers to the practice questions! Ive just looked to the back of my OCR text book and the CD has broken in half, cant believe i didn't notice until now! :frown:

Are the exam cafe questions any good?

Reply 598

mauvetard

Original post by Salliana23

No I think that they are just past paper questions but that is the post that I mean :smile:

It's the link that Ecstacy edited into the post - I've copied and pasted it here http://www.thestudentroom.co.uk/showpost.php?p=30708951&postcount=6

Thankyou a million times over!
And now, I shall get stuck in!
Thankyou! :smile:

Reply 599

Jtking3000

13

Original post by SmartFool

Has anyone got the exam CD uploaded onto their computer anywhere if so, could you possibly do a copy and paste of the answers? i desperately need the answers to the practice questions! Ive just looked to the back of my OCR text book and the CD has broken in half, cant believe i didn't notice until now! :frown:

http://www.qfpost.com/download.do?get=55fdf8ddc8c4ba8fcf13b8f2f3ff8d26

i've uploaded the examination style question answers if thats what you need :smile:

Equilibria, Energetics and Elements (F325) - June 2011 Exam.

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