Entropy influences catalytic reactions in several ways:
1. Activation Energy: During a reaction, the system transitions from reactants to products via an intermediate state (transition state). The entropy change associated with this transition can significantly impact the activation energy. A more ordered transition state (lower entropy) generally requires higher energy to achieve, thus lowering reaction rates.
2. Adsorption and Desorption: In heterogeneous catalysis, reactants adsorb onto the catalyst surface. The entropy of the system decreases upon adsorption because the reactants are more ordered on the surface compared to their free state. This decrease in entropy must be compensated by a favorable enthalpy change to make the adsorption process energetically favorable.
3. Reaction Pathways: Entropy can influence the preferred reaction pathways. Pathways that lead to a higher number of possible microstates (higher entropy) are generally favored, especially at higher temperatures. This principle helps in predicting and optimizing reaction routes.
