Chemistry - Volumetric Analysis I can't do this

[rhuthwaite]

How do I find x in FeC2O4.xH2O. I am told that this is a hydrated salt of 1.75g and was dissolved in acid and made up to 250ml. A 25mL sample of this solution required 29.15mL of standardised 0.0200mol/L KMnO4 solution for complete oxidation.

I worked out n(MnO4-) = cv = 5.83 x 10^-4 moles
and n(C2O4^2-) = 1.4575 x 10^-3 moles
and c(C2O4^2-) = n/v = 0.0583 molL-1
I just don't know how to find x

 

[GCT]

How would you know of the concentration of the C2O4 anion already? You need to employ the stoichiometric equation for the pertinent reaction and then deduce things from there with the mole value you have for the titrant KMnO4.

 

[Borek]

You know number of moles in 25 mL (you have calculated it correctly, BTW), calculate number of moles in 250 mL. Now, number of moles is mass/molar mass - you know mass, you know number of moles, you can calculate molar mass of hydrate. Molar mass is all you need to find x.

 

[jalaldn]

http://antoine.frostburg.edu/chem/senese/101/index.shtml