molarity,Fe2(SO4)3?

Question

1)An aqueous solution contains 3.45 g of iron(III) sulfate, Fe2(SO4)3, per liter. What is the molarity of Fe2(SO4)3?
2)When the compound dissolves in water, the Fe3+ ions and SO42- ions in the crystal go into the solution. What is the molar concentration of each ion in the solution?

Answer 1

1) MW Fe2(SO4)3 = 399.7 g/mole

3.45 g / 399.7 g/mole = 0.00863 moles

0.00863 moles / 1 L = 0.00863 M

2) [Fe3+] = 2 * 0.00863 M = 0.0173 M; [SO42-] = 3 * 0.00863 M = 0.0259 M