Question

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?

• A. Endothermic
• B. Exothermic
• C. Isothermal
• D. Photochemical

Hint:

Key Concept: \( \Delta H < 0 \) → Exothermic, \( \Delta H > 0 \) → Endothermic.

Answer 1

The Correct Option is B

The reaction type is determined by analyzing the provided enthalpy change (\( \Delta H \)): –92.4 kJ/mol. Interpretation follows:

1. Enthalpy Change Definition: Enthalpy change (\( \Delta H \)) quantifies heat absorbed or released in a reaction, measured in kilojoules per mole (kJ/mol).
2. Negative \( \Delta H \) Implication: A negative \(\Delta H\) value indicates that heat is released by the reaction into its environment.
3. Exothermic Reaction Classification: Reactions that release heat (indicated by a negative \(\Delta H\)) are defined as exothermic.

With an enthalpy change of –92.4 kJ/mol, this reaction releases heat, thus it is classified as Exothermic.