<u>Answer:</u> The amount of energy required to convert ammonia back to hydrogen and nitrogen is 45.9 kJ
<u>Explanation:</u>
Endothermic reactions are defined as the reactions in which energy is absorbed in the reaction. The enthalpy change of the reaction is positive.
Exothermic reactions are defined as the reactions in which energy is released in the reaction. The enthalpy change of the reaction is negative.
For the given chemical equation:
In the above reaction, the enthalpy change is negative. So, the reaction is exothermic in nature.
For the reverse reaction, the magnitude of the enthalpy change remains the same but sign for it changes.
Hence, the amount of energy required to convert ammonia back to hydrogen and nitrogen is 45.9 kJ