Question

Which one of the equations below is an endothermic reaction?

A) SrO (s) + CO₂ (g) → SrCO₃ (s) ΔH° = -234 kJ/mol
B) H₂ (g) + F₂ (g) → 2 HF (g) ΔH° = -79.2 kJ/mol
C) H₂ (g) + C (s) + N₂ (g) → 2 HCN (g) ΔH° = 270.3 kJ/mol
D) 2 K (s) + 2 H₂O (l) → 2 KOH (aq) + H2 (g) ΔH° = -393.1 kJ/mol

Answer 1

The equation H₂ (g) + C (s) + N₂ (g) → 2 HCN (g) is an endothermic reaction. Among the given options, the equation C) H₂ (g) + C (s) + N₂ (g) → 2 HCN (g) has a positive enthalpy change of 270.3 kJ/mol, making it an endothermic reaction.

Step-by-step explanation:

An endothermic reaction is one that absorbs heat from the surroundings during the reaction.

The equation for an endothermic reaction can be identified by a positive value for the enthalpy change (ΔH°).

Among the given options, the equation C) H₂ (g) + C (s) + N₂ (g) → 2 HCN (g) has a positive enthalpy change of 270.3 kJ/mol, making it an endothermic reaction.