[hlp805]

I am trying to write a procedure for how to determine the concentration of a metal ion in water, and I am completely lost. My professor told us (we are working in groups of three) that we were to "obtain an unknown aqueous solution containing a salt with a colored cation. Then determine the molarity of the cation in each of the three unknowns, whose concentration will lie in the range from 0.0030M to 0.0900M. Write out your procedure in sufficient detail that another person could repeat your work. Prepare a stock solution of known molarity using the compound containing your cation. To do the calculations you need to decide on a concentration and on a volume you plan to prepare. Continue and prepare the solution. Use the stock solution to prepare several other more dilute solutions. Make the measurements and computations to determine the concentration of your unkown." Honestly, this seems like a foreign language to me right now. I don't understand how to write a procedure for this. Please help ASAP!

Thanks so much!

[Borek]

I suppose it is somehow related to things you have learnt during your chemistry course. Not knowing what you know we can't help, there are way too many analytical methods. My bet is that you are to use some spectroscopic method but that's just a stab in the dark.