Final answer:
The reaction with an enthalpy change of -67 kJ is exothermic, as the negative sign indicates the release of energy to the surroundings.
Step-by-step explanation:
The question you've asked is related to the characterization of chemical reactions based on their enthalpy change. When a reaction has an enthalpy change of -67 kJ, it is classified as an exothermic reaction. This is because the negative sign indicates a release of energy to the surroundings. The concept of enthalpy change can also be understood through examples such as the reaction where if energy is given off and appears on the product side of the thermochemical equation, the reaction is exothermic. Conversely, if energy is required and appears on the reactant side, the reaction is endothermic.
In summary, the enthalpy change of a reaction tells you whether the process is exothermic (energy releasing) or endothermic (energy absorbing). Since your reaction has a negative enthalpy change, we can conclude that it is indeed exothermic.