Chemistry 0620 · IGCSE · Exothermic and endothermic reactions

Exothermic and endothermic reactions — practice question

The reaction equation for ethene reacting with hydrogen is given below. $\text{CH}_2{=}\text{CH}_2(\text{g}) + \text{H}_2(\text{g}) \rightarrow \text{CH}_3{-}\text{CH}_3(\text{g})$ The bond energies are listed below. C=C: $612\,\text{kJ mol}^{-1}$ H-H: $436\,\text{kJ mol}^{-1}$ C-C: $348\,\text{kJ mol}^{-1}$ C-H: $416\,\text{kJ mol}^{-1}$ Calculate the overall energy change for this reaction.

  • A$-284\,\text{kJ mol}^{-1}$
  • B$-132\,\text{kJ mol}^{-1}$
  • C$+132\,\text{kJ mol}^{-1}$
  • D$+284\,\text{kJ mol}^{-1}$

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