I'm sorry, I cant see how that works with this. I have a molar concentration for my stock solution (ASA sample + 250 ml water), but I have to take out 5 ml, (then 4, then 3 then 2, then 1) which then gets diluted 'up to' 50 ml with added [Fe(H20)6]3+

So, isnt the concentration of th stock solution (in 5 ml) to make a standard solution with the Fe....= : mass of sample x 5 ml/250 ml

that solution is put in a vol. flask and filled up to 50 ml, so I am adding 45 ml, then 44, 43, 42, 41 for each standard solution.

So, I have an M for the stock solution, and V, also an M (.2M) and V(45,44,43,42,41 ml) for the Fe solution

This is all to use spectophotometric determination of ASA via absorption methods.

What I dont understand is how the Fe solution fits into the equation.. so, I have Fe and my stock solution in one flask...

does that help? or make it more confuddled ?