Chemistry 0620 · IGCSE · Exothermic and endothermic reactions

Exothermic and endothermic reactions — practice question

The equation represents the reaction of hydrogen with oxygen. $2\text{ H-H} + \text{O=O} \rightarrow 2\text{ H-O-H}$ The bond energies are listed. $\text{H-H} = 436\,\text{kJ mol}^{-1}$ $\text{O=O} = 495\,\text{kJ mol}^{-1}$ $\text{O-H} = 463\,\text{kJ mol}^{-1}$ Which row gives the energy change and reaction type?

  • A$441\,\text{kJ mol}^{-1}$, exothermic
  • B$441\,\text{kJ mol}^{-1}$, endothermic
  • C$485\,\text{kJ mol}^{-1}$, exothermic
  • D$485\,\text{kJ mol}^{-1}$, endothermic

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