Calculate the empirical formula of hydrated ferrous ammonium sulfate, Fea(NH4)b(SO4)c(H2O)d, from the following data.
a. 0.7840 g of the salt gives 0.1600 g Fe2O3(s) when heated strongly in air to constant mass.
b. 0.7840 g of the salt dissolved in water gives 0.9336 g BaSO4(s) when excess BaCl2(aq) is added.
c. When 0.3920 g of the salt is dissolved in water and boiled with excess NaOH(aq), NH3(g) is liberated. When this gas is absorbed in 50.0 mL of 0.10 M HCl(aq), the excess acid remaining after reaction with the NH3(g) requires 30.0 mL of 0.10 M NaOH for neutralization.