BufferSolution

This bio/chemistry app has three main functions.
"Make Solutions" can help you to do the calculations to prepare different concentrations of acids, bases, and biological buffer solutions. The result will inform you how much volume of stock solution, or amount of compounds needed in order to obtain the desired concentration.
"Dilution" is to calculate the volumes of stock and water amount needed to prepare desired solutions.
"pH" can calculate pH/pOH of strong/weak acids/bases by input concentration or pKa/pKb.