Draw a reaction coordinate diagram, making sure to label reactants (R), products (P), intermediates (I), transition states (‡), activation energies ( E_a) , and ∆G°, for each of the following.
(a) an exothermic, one-step reaction

Verified step by step guidance

1. Start by understanding the key components of a reaction coordinate diagram. The x-axis represents the reaction progress, while the y-axis represents the potential energy of the system.
2. Since the reaction is exothermic, the energy of the products (P) will be lower than the energy of the reactants (R). This indicates that energy is released during the reaction, and the overall change in Gibbs free energy (∆G°) will be negative.
3. For a one-step reaction, there will be no intermediates (I). The reaction will proceed directly from reactants (R) to products (P) through a single transition state (‡). The transition state represents the highest energy point along the reaction pathway.
4. Label the activation energy (Eₐ) as the energy difference between the reactants (R) and the transition state (‡). This is the energy barrier that must be overcome for the reaction to proceed.
5. Finally, label ∆G° as the energy difference between the reactants (R) and the products (P). Ensure that the diagram clearly shows the relative energy levels of R, ‡, and P, with P being at a lower energy level than R to reflect the exothermic nature of the reaction.

Key Concepts

Reaction Coordinate Diagram

A reaction coordinate diagram is a graphical representation that illustrates the energy changes during a chemical reaction. The x-axis typically represents the progress of the reaction, while the y-axis shows the energy of the system. Key features include the energy levels of reactants, products, intermediates, and transition states, which help visualize the energy barriers and overall energy change of the reaction.

Exothermic Reaction

An exothermic reaction is a type of chemical reaction that releases energy, usually in the form of heat, to the surroundings. In a reaction coordinate diagram, this is depicted by the products being at a lower energy level than the reactants. The difference in energy between the reactants and products is represented as a negative change in Gibbs free energy (∆G°), indicating that the reaction is energetically favorable.

Activation Energy (Eₐ)

Activation energy (Eₐ) is the minimum energy required for a reaction to occur, representing the energy barrier that must be overcome for reactants to transform into products. In a reaction coordinate diagram, it is illustrated as the energy difference between the reactants and the highest point of the transition state. Understanding activation energy is crucial for predicting reaction rates and the feasibility of a reaction.