Question

In an Fe2(SO4)3 solution the concentration of SO42−is 0.25 mol L−1. What is the concentration of solute?

Answer 1

From the molecular formula of iron (III) sulfate, we can determine that for each mole of solute that is dissolved, three sulfate ions will be put into solution. We can use some dimensional analysis to show what the concentration of the solute would be:\[0.25M\ SO_4^{2-} \times (\frac{1M\ Fe_2(SO_4)_3}{3M\ SO_4^{2-}})=0.083M\ Fe_2(SO_4)_3\]