Chapter 30

A solid sample containing some \(\mathrm{Fe}^{2+}\) ion weighs \(1.264 \mathrm{g}\). It requires \(38.67 \mathrm{mL}, 0.02487 \mathrm{M} \mathrm{KMnO}_{4}\) to titrate the \(\mathrm{Fe}^{2+}\) in the dissolved sample to a pink end point. a. How many moles of \(\mathrm{MnO}_{4}^{-}\) ion are required? b. How many moles of \(\mathrm{Fe}^{2+}\) are there in the sample? c. How many grams of iron are there in the sample? d. What is the mass percent of Fe in the sample?

What is the mass percent of Fe in iron(II) ammonium sulfate hexahydrate, \(\mathrm{Fe}\left(\mathrm{NH}_{4}\right)_{2}\left(\mathrm{SO}_{4}\right)_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O} ?\)