You have been given the task by your adviser of making a 1-L of a solution with a calcium activity {Ca2+} of 1.3*10^-4 M and he wants you to make two different ways. One in 0.05M KCl and the second in 0.1M MgCl2. How much CaCl2 do you need to add to 1-L of water or (appropriate salt solution) to make each solution and achieve the desired activity? Assume all salts completely dissociate and use the Davies equation for activity coefficients.