Chemistry 0620 · IGCSE · Exothermic and endothermic reactions

Exothermic and endothermic reactions — practice question

The reaction of hydrogen with oxygen gives out $486\ \text{kJ mol}^{-1}$ of energy. $2\text{H}_2(\text{g}) + \text{O}_2(\text{g}) \rightarrow 2\text{H}_2\text{O}(\text{g})$ The bond energy of H-H is $436\ \text{kJ mol}^{-1}$ and that of H-O is $464\ \text{kJ mol}^{-1}$. Calculate 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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