A sample of hydrated iron(II) sulfate, FeSO₄ · xH₂O, of mass 0.695 g is dissolved in dilute sulfuric acid. It needs 25.0 mL of 0.0200 mol L⁻¹ potassium permanganate to reach the end point: MnO₄⁻ + 5 Fe²⁺ + 8 H⁺ → Mn²⁺ + 5 Fe³⁺ + 4 H₂O. What is the value of x? Atomic masses in g mol⁻¹: H 1.0, O 16.0, S 32.0, Fe 56.0.

ChemistryHardHigh School (11–12)Atoms and Molecules › Stoichiometry and Concentration Olympiad

A sample of hydrated iron(II) sulfate, $\text{FeSO}_4 \cdot x\text{H}_2\text{O}$ , of mass $0.695\ \text{g}$ is dissolved in dilute sulfuric acid. It needs $25.0\ \text{mL}$ of $0.0200\ \text{mol L}^{-1}$ potassium permanganate to reach the end point: $\text{MnO}_4^- + 5\,\text{Fe}^{2+} + 8\,\text{H}^+ \rightarrow \text{Mn}^{2+} + 5\,\text{Fe}^{3+} + 4\,\text{H}_2\text{O}$ . What is the value of $x$ ? Atomic masses in $\text{g mol}^{-1}$ : H 1.0, O 16.0, S 32.0, Fe 56.0.

Type your answer as a number (a decimal point is allowed). A wrong answer may cost marks.

← All Quizzes

← A 0.500 g piece of brass (copper and zinc) is dissolved in acid. An excess of KI is added, which reacts only with the copper: 2 Cu²⁺ + 4 I⁻ → 2 CuI + I₂. The iodine set free needs 47.2 mL of 0.100 mol L⁻¹ sodium thiosulfate: I₂ + 2 S₂O₃²⁻ → 2 I⁻ + S₄O₆²⁻. What is the percentage of copper in the brass by mass, to the nearest integer? Atomic masses in g mol⁻¹: Cu 63.5.Magnesium burns in nitrogen: 3 Mg + N₂ → Mg₃N₂. A mixture of 6.0 g of Mg and 4.0 g of N₂ is heated, and the reaction goes only to 80% of the extent that the limiting reagent allows. What mass of N₂ is left when the reaction stops? Atomic masses in g mol⁻¹: N 14.0, Mg 24.0. →

More onAtoms and Molecules › Stoichiometry and Concentration

Discussion (0)

Loading…

Discussion (0)

Problems on this topic