Written by the Fiveable Content Team โข Last updated September 2025
Written by the Fiveable Content Team โข Last updated September 2025
Definition
A bimolecular reaction is a chemical reaction that involves two reactant molecules colliding and reacting to form products. The rate of such reactions depends on the concentration of both reactants.
5 Must Know Facts For Your Next Test
The rate law for a bimolecular reaction is generally expressed as $rate = k[A][B]$, where $k$ is the rate constant and $[A]$ and $[B]$ are the concentrations of the reactants.
Bimolecular reactions have a second-order overall reaction order because the sum of the exponents in their rate law is two.
The units of the rate constant $k$ for a bimolecular reaction are typically $\text{M}^{-1}\text{s}^{-1}$.
Examples of bimolecular reactions include substitution reactions (SN2) and certain types of enzyme-catalyzed processes.
Temperature, catalysts, and solvent can significantly influence the rate constant $k$ in bimolecular reactions.
A type of chemical reaction where the overall order is two, meaning that either one reactant's concentration squared or two different reactants' concentrations each raised to the first power determine the rate.