Chemistry 0620 · IGCSE · Exothermic and endothermic reactions

Exothermic and endothermic reactions — practice question

Nitrogen combines with hydrogen to make ammonia. $\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3$ This reaction releases heat. The bond energies are listed in the table. Bond energies (in $\text{kJ/mol}$): - $\text{N}\equiv\text{N}$: $945$ - $\text{H}-\text{H}$: $436$ - $\text{N}-\text{H}$: $390$ Calculate the energy change for this reaction.

  • A$-1473\,\text{kJ/mol}$
  • B$-87\,\text{kJ/mol}$
  • C$87\,\text{kJ/mol}$
  • D$1473\,\text{kJ/mol}$

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