Bimolecular reaction

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

1. 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.
2. Bimolecular reactions have a second-order overall reaction order because the sum of the exponents in their rate law is two.
3. The units of the rate constant $k$ for a bimolecular reaction are typically $\text{M}^{-1}\text{s}^{-1}$.
4. Examples of bimolecular reactions include substitution reactions (SN2) and certain types of enzyme-catalyzed processes.
5. Temperature, catalysts, and solvent can significantly influence the rate constant $k$ in bimolecular reactions.

Review Questions

• What is the general form of the rate law for a bimolecular reaction?
• Why are bimolecular reactions considered second-order reactions?
• How can temperature affect the rate constant in a bimolecular reaction?

Related terms

Rate Law:

An equation that links the rate of a reaction to the concentration of reactants, often in the form $rate = k[A]^m[B]^n$.

Second-Order Reaction:

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.

Activation Energy:

The minimum energy required for a chemical reaction to occur, often denoted as $E_a$.