[maiass]

HI! I've been trying to come up with the formula to calculate the percentage of Cu and Zn in a sample of Brass   I cannot do it!), my brain has gone dead already, The question is this: I did a Iodometry to find the amount of Cu, using Na2S2O3 and I as an indicator, and then asgain the same sample with EDTA to find the amount of Zn, I know, the M of Na2S2O3 and EDTA, the weight of the initiall sample, the volumes of the original dilution , and the volume taken for the experiment as well as the amunt of Na2S2O3 in each try. From this I need to calculate the % of Cu and then of Zn (I have Molecular weights too).

I hope you can help me I don't know what else to do...Thanks!

[Borek]

Write down all reaction equations, balance them, find the stoichiometry, calculate moles of Cu and Zn, calculate the masses - and you are ready.