Final answer:
To determine if a chemical reaction is endothermic or exothermic, we need to look at the enthalpy change of the reaction. If the change is positive, the reaction is endothermic; if the change is negative, the reaction is exothermic. In the given equations, H₂ + F₂ → 2HF is endothermic.
Step-by-step explanation:
If the enthalpy change is positive, the reaction is endothermic. If the enthalpy change is negative, the reaction is exothermic.
In the given equations,
H₂ + F₂ → 2HF: The equation states that 130 kcal are released, indicating that the reaction is exothermic.
2HBr → H₂ + Br₂: The equation does not have information about the enthalpy change, so we cannot determine if the reaction is endothermic or exothermic.
Therefore, the equation H₂ + F₂ → 2HF is endothermic.