To determine how the reaction can be described, let’s analyze the given thermochemical equation:
[tex]\[ \text{CaCO}_3(s) + 179 \text{ kJ} \rightarrow \text{CO}_2(g) + \text{CaO}(s) \][/tex]
1. Understanding the Reaction:
The equation shows that calcium carbonate ([tex]\(\text{CaCO}_3\)[/tex]) reacts to produce carbon dioxide ([tex]\(\text{CO}_2\)[/tex]) and calcium oxide ([tex]\(\text{CaO}\)[/tex]). Along with this transformation, 179 kJ of energy is absorbed.
2. Energy Consideration:
- The term " + 179 kJ" on the reactant side indicates that the reaction requires an input of energy to proceed.
- When a reaction absorbs energy from the surroundings, it is called an endothermic reaction.
3. Classifying the Reaction:
- Endothermic Reaction: Since 179 kJ of energy is absorbed, the reaction requires this energy to break the bonds in calcium carbonate. This characterizes the reaction as endothermic.
- Activation Energy: The activation energy is the minimum energy required to initiate a reaction. While the reaction absorbs energy, the given information does not specify the exact magnitude of the activation energy (low or high). Hence, we cannot definitively describe the activation energy without such specific details.
- Exothermic Reaction: This type of reaction releases energy, but the provided equation clearly shows energy absorption, not release.
By comparing all the details, the correct description for the reaction is that it absorbs energy, categorizing it as an endothermic reaction.
Thus, the best description of the reaction is:
B. It is endothermic.
