To determine whether the reactions are endothermic or exothermic, we need to examine the energy dynamics involved in each reaction. Here is the detailed step-by-step analysis:
1. Understand the Terminology:
- An endothermic reaction absorbs energy from its surroundings, typically in the form of heat. This means the reaction requires an input of energy to proceed.
- An exothermic reaction releases energy to its surroundings, usually as heat or light. This means the reaction produces energy.
2. Analyzing Reaction A:
- This reaction is: [tex]\( 6 CO_2( a ) + 6 H_2O \left(h+\right.\text{sunlight} + C_6H_{12}O_6( aq ) + 6 O_2(a) \)[/tex]
- The key component here is sunlight. Sunlight provides the energy required to drive this reaction, which suggests that the reaction absorbs energy from the surroundings. Therefore, Reaction A is endothermic.
3. Analyzing Reaction B:
- This reaction is: [tex]\( 2 H_2(g) + O_2(g) \rightarrow 2 H_2O ( g ) + \text{ energy} \)[/tex]
- Here, the reaction equation explicitly states that energy is released as a product of the reaction. This indicates that energy is being emitted to the surroundings. Therefore, Reaction B is exothermic.
Based on this analysis, we can conclude:
- Reaction A is endothermic because it requires an input of energy (sunlight).
- Reaction B is exothermic because it releases energy.
Thus, the correct answer is:
B. Reaction A is endothermic, and reaction B is exothermic.
