Twenty dietary iron tablets with a total mass of 22.131 g were ground and mixed thoroughly. Then

Question:

Twenty dietary iron tablets with a total mass of 22.131 g were ground and mixed thoroughly. Then 2.998 g of the powder were dissolved in HNO3 and heated to convert all iron into Fe3+. Addition of NH3 precipitated Fe2O3 ∙ xH2O, which was ignited to give 0.264 g of Fe2O3 (FM 159.69). What is the average mass of FeSO4 ∙ 7H2O (FM 278.01) in each tablet?