Chemistry 9701 · AS & A Level · Atoms, molecules and stoichiometry

Atoms, molecules and stoichiometry — practice question

A portion of potassium oxide, $\text{K}_2\text{O}$, is added to $250\,\text{cm}^3$ of distilled water. A $25.0\,\text{cm}^3$ aliquot of the resulting solution is then titrated with sulfuric acid having a concentration of $2.00\,\text{mol dm}^{-3}$. For full neutralisation, $15.0\,\text{cm}^3$ of this sulfuric acid is required. What mass of potassium oxide had initially been dissolved in $250\,\text{cm}^3$ of distilled water?

  • A$2.83\,\text{g}$
  • B$28.3\,\text{g}$
  • C$47.1\,\text{g}$
  • D$56.6\,\text{g}$

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