The Molarity App from Sigma-Aldrich(R) is a chemistry calculator tool that generates lab-ready directions describing how to prepare an acid or base solution of a specified molarity or normality from a concentrated acid or base solution. A second tab includes a general molarity function that calculates the mass of any reagent needed to prepare a given volume of solution of desired molarity. A third tab features a stock dilution function that calculates how to dilute a stock solution of any known molarity to your desired volume and molarity.