Chemistry 0620 · IGCSE · The mole and the Avogadro constant

The mole and the Avogadro constant — practice question

When calcium carbonate is heated, it breaks down to give calcium oxide and carbon dioxide gas. The reaction can be written as: $\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2$ A sample of $225\,\text{kg}$ of calcium carbonate is heated until the mass stops changing. The mass of calcium oxide produced is $85\,\text{kg}$. Calculate the percentage yield.

  • A37.8%
  • B47.2%
  • C67.5%
  • D85.0%

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