Determine the change in enthalpy ( H) from Diagram A.

The potential energy of the reactants is $208.2 \text{ kJ}$.
The potential energy of the products is $86.5 \text{ kJ}$.

Since the change in enthalpy ($\Delta H$) is negative, the reaction releases energy.

The reaction is EXOTHERMIC.
Reason: The potential energy of the products ($86.5 \text{ kJ}$) is lower than the potential energy of the reactants ($208.2 \text{ kJ}$), indicating that energy is released during the reaction.

5.1.2

The shaded area to the right of line P in Diagram B represents the number of particles with kinetic energy equal to or greater than the activation energy. These are the particles that possess sufficient energy to overcome the activation barrier and react.

5.1.3

The potential energy of the reactants is $208.2 \text{ kJ}$.
The potential energy of the activated complex (transition state) for the uncatalyzed reaction is $240.8 \text{ kJ}$.

The letter X in Diagram B represents the activation energy of the uncatalyzed reaction, as it is the higher activation energy.

The numerical value represented by the letter X is $\text{32.6 kJ}$.