Let's carefully analyze the reaction pathway and the corresponding energy diagram.
The given reaction is:
[tex]\[ 2C(s) + H_2(g) + 227.4 \text{ kJ} \rightarrow C_2H_2(g) \][/tex]
In energy diagrams that represent the potential energy changes during a chemical reaction, different stages are typically labeled to illustrate the energy levels of the reactants, products, and intermediates. Here’s a step-by-step breakdown of what each label generally represents in a typical energy diagram:
1. Starting Materials (Reactants):
- This is the energy level of the reactants at the beginning of the reaction.
2. Activation Energy Peak:
- This represents the maximum energy that must be overcome for the reaction to proceed (the peak of the energy barrier).
3. Transition State:
- The transition state is the highest point on the energy diagram, often coinciding with the activation energy peak, where bonds are in the process of breaking and forming.
4. Products:
- This is the energy level of the products after the reaction has occurred.
Given this information, we're asked to identify which number represents the potential energy of the products [tex]\( C_2H_2(g) \)[/tex].
Since the products are formed after the reaction has absorbed or released energy, their energy level is represented in the final step of the reaction pathway, which typically is the last labeled point in an energy diagram.
Therefore, the number that represents the potential energy of the products in the energy diagram is:
D. (4)
