Calculating concentration in molarity from volume?

Question

Hi,
Basically im trying to find the extinction coefficient of a substance but before i can proceed i need to find the conc in molarity of the substance i used.
Well i used methyl orange (327.33g) and diluted it to a factor of 1:10 with distilled water, i used 2.5mg/l of MO with 22.5 water, i need to find the conc, plaese can any one help a.s.a.p!!!!!!
Thanx

Answer 1

It is 1/10 as concentrated as in the first solution.

But how concentrated was that? Is 327.33 the formula mass? If not,what is it?