Termolecular reaction

Definition

A termolecular reaction is a chemical reaction that involves three reactant molecules colliding simultaneously to form products. These types of reactions are rare due to the low probability of three particles colliding at the same time with the correct orientation and sufficient energy.

5 Must Know Facts For Your Next Test

1. Termolecular reactions have a third-order rate law, typically written as $rate = k[A][B][C]$.
2. The frequency of termolecular collisions is much lower than unimolecular or bimolecular reactions due to the necessity of three molecules colliding simultaneously.
3. These reactions often proceed via stepwise mechanisms involving intermediate species rather than through a single collision event.
4. Termolecular reactions are more common in gas-phase chemistry where molecular movements and collisions are more frequent.
5. Examples include the formation of ozone from oxygen molecules and atomic oxygen: $2O_2 + O \rightarrow O_3 + O_2$.

Review Questions

Related terms

Unimolecular Reaction: A type of chemical reaction involving only one reactant molecule that undergoes decomposition or rearrangement.

Bimolecular Reaction: $A + B \rightarrow Products$: A chemical reaction involving two reactant molecules colliding and reacting to form products.

Reaction Mechanism:

The step-by-step sequence of elementary reactions by which overall chemical change occurs.