For each of the following precipitation reactions, calculate how many grams of the first reactant are necessary to completely react with 17.9 g of the second reactant.
a. 2 KI (aq) + Pb (NO3)2 (aq) --> PbI2 (s) + 2KNO3 (aq)
b. Na2CO3 (aq) + CuCI2 (aq) --> CuCO3 (s) + 2 NaCI (aq)
c. K2SO4...