When we need to make solutions with multiple concentrations, we usually make up a highly concentrated solution called a "stock solution." This stock solution is then diluted to make other solutions of known concentration, sometimes referred to as "standards."

You make a stock solution using 12.60 mg of a dye with a molar mass of 271.1 g/mol and you add water until you reach a volume of 500.0 mL. What is the concentration of the dye in this stock solution? Give your answer in all of the units requested.

If you use 11.0 mL of the stock solution (from the previous question) and add water to make a new solution with a total volume of 50.0 mL, what is the concentration of the dye in the new solution (in mM)?