Urgent: Chemistry A2 Coursework

Hi, I am doing a coursework on the estimation of iron(II) and iron(III) in a mixture containing both. This is a volumetric procedure to determine the percentage of iron 2 and 3. I am provided with 200cm3 of solution containing between 1.1g and 1.3g of iron ions as a mixture and the two ions are present to at least 30% by mass.

I don't know where to start with this courseowrk? What concentrations and quanities of soultions should I use?
What method should I use?

I've been researching for 5 days and have found very little to do with this coursework. I know that manganate has something to do with Iron but how do you link this in? Where do I start from? PLEASE HELP!! THANKS.

Reply 1

ImperceptibleNinja

Hallo,
I would imagine you've tried searching for information on each kind of ion and the reactions seperately - that would probably be my first plan of attack. Also, i would imagine that one kind of ion would react more easily than the other, so perhaps you could sort that ion out first then deal with the other one after. (aha, i have found out that the 3+ ion is more stable than the 2+ ion, so you could maybe get rid of the 2+ ion first?)
'chemistry: a unified approach' has a table of 'coloured precipitates from solutions of some transition metal ions with alkali', and Fe[2+] gives 'dirty green Fe(OH)2', while Fe[3+] gives 'rust-brown Fe(OH)3'. Maybe that could be used to your advantage? If there was some way of seperating the two, then you could probably work it out by dissolving them in something else and... [yes, that line of thought needs more research, sorry].
My data booklet [Higher & AH] has a solubitity chart - apparently Iron(II) iodide is 'very soluble', but there is 'no data' for the solubility of iron(III)iodide. Either that means the whole thing explodes to quickly for them to work out if it's soluble, or it might be useful :smile:

Sorry that all of that's pretty vague and useless....i'm hoping that maybe there'll be something that might turn out to be handy. I'll keep looking for stuff and let you know if i find anything that might be a bit more useful than what i've blethered on about already. I hope that you get the coursework sorted out and that it goes well.