An experiment was carried out to find the value of in hydrated iron(II) ethanedioate,

CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance

Problem

An experiment was carried out to find the value of

n

in hydrated iron(II) ethanedioate,

\mathrm{FeC_2O_4}\cdot n\mathrm{H_2O}

1.71\ \text{g}

of the compound was dissolved in deionised water and made up to

250\ \text{cm}^3

of solution in a volumetric flask. When

25.0\ \text{cm}^3

of this solution was acidified using an excess of dilute sulfuric acid, it reacted with

28.50\ \text{cm}^3

0.0200\ \text{mol dm}^{-3}

potassium manganate(VII). (1) Deduce the number of moles of

\mathrm{MnO_4^-}

that react with one mole of

\mathrm{FeC_2O_4}\cdot n\mathrm{H_2O}

. Remember that both the

\mathrm{Fe^{2+}}

and

\mathrm{C_2O_4^{2-}}

ions react. (2) Find the relative formula mass of hydrated iron(II) ethanedioate and the value of

n