Iron is an element that is essential in the human diet. Some people need to take iron supplement tablets to ensure an adequate intake of iron. You will investigate the mass of iron in an iron supplement tablet by titrating a solution with potassium manganate(VII). $$\[ \begin{gathered} \mathrm{Fe}^{2+}(\mathrm{aq}) \rightarrow \mathrm{Fe}^{3+}(\mathrm{aq})+\mathrm{e}^{-} \\ \mathrm{MnO}_{4}^{-}(\mathrm{aq})+8 \mathrm{H}^{+}(\mathrm{aq})+5 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{2+}(\mathrm{aq})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \end{gathered} \]$$ FB 1 is an aqueous solution of iron supplement tablets made by dissolving 14 tablets in $$\(1.00 \mathrm{dm}^{3}\)$$ of solution. The iron in each tablet is iron(II) sulfate, $$\(\mathrm{FeSO}_{4} \bullet 7 \mathrm{H}_{2} \mathrm{O}\)$$. FB 2 is $$\(0.0100 \mathrm{~mol} \mathrm{dm}^{-3}\)$$ acidified aqueous potassium manganate(VII), $$\(\mathrm{KMnO}_{4}\)$$. FB 3 is dilute sulfuric acid, $$\(\mathrm{H}_{2} \mathrm{SO}_{4}\)$$. Calculations (i) Give your answers to (c)(ii), (c)(iii) and (c)(iv) to an appropriate number of significant figures. (ii) Calculate the amount, in mol, of manganate(VII) ions in the volume of FB 2 in (b). amount of $$\(\mathrm{MnO}_{4}{ }^{-}=\)$$ mol (iii) Use your answer to (c)(ii) and the equations at the start of the question to calculate the concentration, in $$\(\mathrm{mol} \mathrm{dm}^{-3}\)$$, of iron(II) ions in FB 1. concentration of $$\(\mathrm{Fe}^{2+}=\)$$ $$\(\mathrm{mol} \mathrm{dm}^{-3}\)$$ (iv) Use your answer to (c)(iii) to calculate the concentration, in $$\(\mathrm{gdm}^{-3}\)$$, of iron(II) ions in FB 1. concentration of $$\(\mathrm{Fe}^{2+}=\)$$ $$\(\mathrm{g} \mathrm{dm}^{-3}\)$$ (v) The manufacturer of the iron supplement tablets used to make FB 1 claims that each tablet contains a minimum of 150 mg of $$\(\mathrm{Fe}^{2+}\)$$. Use your answer to (c)(iv) and the information given about FB 1 to determine whether this claim is correct. Show your working.

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