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

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Reply 700

arvin_infinity

Original post by LifeIsGood

I remember reading something due to the length of Cl bonds in the OCR textbook :s-smilie:

Most probs. you are referring to size of the chloride ligands which is larger than the water molecules

Original post by ChrisE2

I think it's the same for every transition metal except the book uses the example of chromium, chromium will still be able to have only 4 Cl- ligands

This was posted from The Student Room's iPhone/iPad App

Book says that? pls tell me where

(edited 11 years ago)

Reply 701

Killjoy-

Original post by arvin_infinity

No worries..any idea why ligand substitution with Cl ligands is very different for Cr!?

In a sense that only 2 water molecules is replaced by cl^-1 ligands

There's a little bit about at the end of this page, but I don't know how necessary it is.
http://chemed.chem.wisc.edu/chempaths/GenChem-Textbook/Transition-Metal-Ions-in-Aqueous-Solutions-1055.html

Reply 702

user977153

Do we need to memorise the ionic equations for iodine, manganate and chromium?

Reply 703

ChrisE2

Original post by arvin_infinity

Most probs. you are referring to size of the chloride ligands which is larger than the water molecules

Book says that? pls tell me where

See killjoys link, it has examples

This was posted from The Student Room's iPhone/iPad App

Reply 704

sumsum123

Original post by arvin_infinity

Book says that? pls tell me where

Check top of page 215 :smile:

Reply 705

walkbesideme

Original post by DoctorVertigo

Do we need to memorise the ionic equations for iodine, manganate and chromium?

As far as i'm aware no but it might be good to remember them so it's not as much of a shock should they appear in the exam :smile:

Reply 706

Swifttt

Anyone seen that past paper question which is like how does platin treat cancer? I did that paper earlier and I swear it's a not in the book anywhere.

Reply 707

niaghez

the stupid long questions on the past papers are so hard but then i look at the mark scheme and i get them, problem is im not going to have the mark scheme with me :frown:

Reply 708

niaghez

Original post by Swifttt

Anyone seen that past paper question which is like how does platin treat cancer? I did that paper earlier and I swear it's a not in the book anywhere.

yeah its in a green box on one of the pages in the transition elements

Reply 709

Swifttt

^
Crap I defintely haven't learnt anything in the green boxes, I always thought they were like interesting but irrelevant information :/

Reply 710

LifeIsGood

Original post by niaghez

the stupid long questions on the past papers are so hard but then i look at the mark scheme and i get them, problem is im not going to have the mark scheme with me :frown:

Which ones?
The buffer solutions always want the same points written down

Reply 711

Oromis263

Original post by Swifttt

Anyone seen that past paper question which is like how does platin treat cancer? I did that paper earlier and I swear it's a not in the book anywhere.

You've probably looked at the mark scheme, but it is in the specification, and the reasoning is:

The cis-platin binds with the DNA in cancerous cells, preventing the replication of DNA.(good shout Otrivine for calling me up on not specifying how this is beneficial :smile:

)

Or at least, that is one way to answer it.

(edited 11 years ago)

Reply 712

maddy93x

oh my days the jan2011 and june 2011 papers were hard!
how did people find them?
do u think we are going to get a hard paper this time? considering jan 2012 wasnt that bad?

Reply 713

otrivine

Original post by Oromis263

You've probably looked at the mark scheme, but it is in the specification, and the reasoning is:

The cis-platin binds with the DNA in cancerous cells. (or at least, that is one way to answer it).

yes and that it prevents replication of DNA

Reply 714

niaghez

Original post by LifeIsGood

Which ones?
The buffer solutions always want the same points written down

no those ones im okay with its mostly the ones that require you to form the equations and work out like the percentage of something in brass. like i know what i have to do but its hard without the equations :/

Reply 715

sumsum123

Original post by maddy93x

oh my days the jan2011 and june 2011 papers were hard!
how did people find them?
do u think we are going to get a hard paper this time? considering jan 2012 wasnt that bad?

I found them okay. I sat the Jan 2012 paper and it was not bad at all. Just scared they are going to kill us in June "/ . Hope not..

Reply 716

niaghez

Original post by maddy93x

oh my days the jan2011 and june 2011 papers were hard!
how did people find them?
do u think we are going to get a hard paper this time? considering jan 2012 wasnt that bad?