Chemistry 5070 · O Level · The mole and the Avogadro constant

The mole and the Avogadro constant — practice question

If excess aqueous barium chloride is added to $25.0\,\text{cm}^3$ of $1.00\,\text{mol dm}^{-3}$ sodium sulfate, a white precipitate of barium sulfate is produced. $\text{Na}_2\text{SO}_4\text{(aq)} + \text{BaCl}_2\text{(aq)} \rightarrow \text{BaSO}_4\text{(s)} + 2\text{NaCl(aq)}$ This precipitate is then filtered, washed, dried and weighed. A mass of $5.36\,\text{g}$ barium sulfate is obtained. Calculate the percentage yield of barium sulfate. $[M_r:\ \text{Na}_2\text{SO}_4,\ 142;\ \text{BaCl}_2,\ 208;\ \text{BaSO}_4,\ 233;\ \text{NaCl},\ 58.5]$

  • A$2.3\%$
  • B$27\%$
  • C$92\%$
  • D$97\%$

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