Question

Sketch a potential energy diagram for the reaction below.

Label everything you can [K/U: 3 marks]. AB -> B + A ΔH = +66.4kJ

Answer 1

To sketch a potential energy diagram for an endothermic reaction (AB → B + A, ΔH = +66.4kJ), one must draw the reaction progress and potential energy axes, show the reactants at a lower energy level than the products, indicate the higher activation energy peak, and label the enthalpy change (ΔH) reflecting the energy absorbed.

Step-by-step explanation:

To sketch a potential energy diagram for the reaction AB → B + A with a ΔH of +66.4kJ, we need to illustrate the energy changes throughout the reaction. Below are the steps and labeled components:

1. Begin by drawing the horizontal axis, representing the reaction progress, and the vertical axis, indicating the potential energy of the system.
2. Mark the initial energy level of the reactants, AB, on the vertical axis.
3. Since the ΔH is positive, this means the reaction is endothermic; thus, the products will have a higher energy level than the reactants. Draw a second line above the reactants to represent the products, indicating an increase in potential energy.
4. The peak of the diagram represents the activation energy (Ea) needed for the reaction to proceed. The specific Ea value is not given, but it should be drawn as a peak between the reactants and products.
5. The enthalpy change, ΔH, of the reaction should be labeled as the difference in energy between the reactants and products.

As a result, the potential energy diagram will show an upward curve from the reactants to the transition state, then descending toward the products, reflecting the endothermic nature of the reaction.