For the reaction:
\( \text{N}_2(g) + 3\text{H}_2(g) \rightarrow 2\text{NH}_3(g) \),
the enthalpy change (\( \Delta H \)) is –92.4 kJ/mol.
What type of reaction is it?
Show Hint
Key Concept: \( \Delta H < 0 \) → Exothermic, \( \Delta H > 0 \) → Endothermic.
- Endothermic
- Exothermic
- Isothermal
- Photochemical
The Correct Option is B
Solution and Explanation
The given chemical reaction is: 2N(g)+3H(g)→2NH3(g) with an enthalpy change (\(\Delta H\)) of –92.4 kJ/mol.
To determine the type of reaction, we analyze the sign of the enthalpy change (\(\Delta H\)):
- In an exothermic reaction, energy is released to the surroundings and \(\Delta H\) is negative.
- In an endothermic reaction, energy is absorbed and \(\Delta H\) is positive.
- An isothermal process is typically a physical process where temperature remains constant, not defined by \(\Delta H\).
- A photochemical reaction is driven by the absorption of light, not by \(\Delta H\).
Given that \(\Delta H = -92.4\) kJ/mol, it indicates the system releases energy.
Thus, the reaction is exothermic.
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