An ore is to be analyzed for its iron content by an...

An ore is to be analyzed for its iron content by an oxidation-reduction titration with permanganate ion. A $4.24$ -gram sample of the ore is dissolved in hydrochloric acid and passed over a reducing agent so that all the iron is in the form $\mathrm{Fe}^{2+}(a q)$. The $\mathrm{Fe}^{2+}(a q)$ is completely oxidized by $31.6 \mathrm{~mL}$ of a $0.0512-\mathrm{M}$ aqueous solution of $\mathrm{KMnO}_{4}(a q) .$ The unbalanced equation for the reaction is $$ \begin{aligned} &\mathrm{KMnO}_{4}(a q)+\mathrm{HCl}(a q)+\mathrm{FeCl}_{2}(a q) \rightarrow \\ &\mathrm{MnCl}_{2}(a q)+\mathrm{FeCl}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{KCl}(a q) \end{aligned} $$ Calculate the amount of iron in the sample and its mass percentage in the ore.

An ore is to be analyzed for its iron content by an oxidation-reduction titration with permanganate ion. A $4.24$ -gram sample of the ore is dissolved in hydrochloric acid and passed over a reducing agent so that all the iron is in the form $\mathrm{Fe}^{2+}(a q)$. The $\mathrm{Fe}^{2+}(a q)$ is completely oxidized by $31.6 \mathrm{~mL}$ of a $0.0512-\mathrm{M}$ aqueous solution of $\mathrm{KMnO}_{4}(a q) .$ The unbalanced equation for the reaction is
$$
\begin{aligned}
&\mathrm{KMnO}_{4}(a q)+\mathrm{HCl}(a q)+\mathrm{FeCl}_{2}(a q) \rightarrow \\
&\mathrm{MnCl}_{2}(a q)+\mathrm{FeCl}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{KCl}(a q)
\end{aligned}
$$
Calculate the amount of iron in the sample and its mass percentage in the ore.

Key Concepts

Redox Titration

Redox titration is an analytical method in which a chemical reaction involving electron transfer (oxidation and reduction) is used to determine the concentration of an analyte. It involves adding a titrant of known concentration to the analyte until the reaction reaches an endpoint, often signaled by a color change or an indicator, allowing for the quantification of the substance being analyzed.

Reaction Stoichiometry and Balanced Equations

This concept involves establishing and using the balanced chemical equation to determine the mole-to-mole relationships between reactants and products in a redox reaction. Precise stoichiometric coefficients are crucial for linking the amount of titrant used to the amount of analyte present, ensuring calculations of substance quantities are accurate.

Mole Concept and Concentration Calculations

The mole concept is fundamental in chemistry for quantifying substances. It relates the mass of a substance to the number of entities (atoms, molecules, ions) present via its molar mass, and when combined with concentration and volume (moles = molarity × liters), it enables the conversion between mass, volume, and number of moles in quantitative chemical analysis.

Mass Percentage Determination

Mass percentage is a measure used to express the concentration of a component in a mixture or compound relative to the total mass. It is calculated by dividing the mass of the specific component by the total mass of the sample and multiplying by 100, providing a way to quantify the purity or composition of a substance in analytical chemistry.

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