Chemistry 0620 · IGCSE · Exothermic and endothermic reactions

Exothermic and endothermic reactions — practice question

When hydrogen reacts with oxygen, $486\,\text{kJ mol}^{-1}$ of energy is released. $\text{2H}_2(g) + \text{O}_2(g) \rightarrow \text{2H}_2\text{O}(g)$ The H-H bond energy is $436\,\text{kJ mol}^{-1}$ and the H-O bond energy is $464\,\text{kJ mol}^{-1}$. Determine the bond energy of O=O.

  • A$430\,\text{kJ mol}^{-1}$
  • B$458\,\text{kJ mol}^{-1}$
  • C$498\,\text{kJ mol}^{-1}$
  • D$984\,\text{kJ mol}^{-1}$

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