Rucete ✏ Chemistry In a Nutshell
1. What Is a Reaction Mechanism?
A reaction mechanism is the step-by-step sequence of elementary reactions that show how reactants are converted to products.
Each elementary step represents a single molecular event like bond-breaking or bond-forming.
2. Elementary Reactions
These are individual steps in the overall reaction.
They show the actual collisions and rearrangements of atoms or molecules.
3. Rate-Determining Step (RDS)
The slowest elementary step in the mechanism.
It acts as a bottleneck, controlling the overall reaction rate.
The rate law of the entire reaction is based on the rate-determining step.
4. Catalysis and Activation Energy
A catalyst provides an alternative reaction pathway with lower activation energy (Ea).
Catalysts:
Increase the rate of both forward and reverse reactions.
Do not get consumed in the reaction.
Do not affect the equilibrium position, only the rate at which equilibrium is reached.
In a nutshell
Rate-determining step = slowest = rate law basis.
Catalyst = faster path, same destination.