Dynamic equilibrium — Science definition
The state in which the forward and reverse reactions occur at equal rates, so the concentrations of reactants and products stay constant.
Where it is taught
- Chemical Equilibrium — Rates & Equilibrium, Physical Science: Chemistry, Grade 11
In use
At dynamic equilibrium, forward and reverse reaction rates are equal and macroscopic composition remains stable under fixed conditions.
Chemical Equilibrium
Questions using dynamic equilibrium
Problem 1
At dynamic equilibrium…
- the reaction has completely stopped
- the forward and reverse reactions occur at equal rates
- reactants and products are always present in equal amounts
- no more collisions occur
Answer and explanation
the forward and reverse reactions occur at equal rates
Equilibrium is dynamic: both reactions still run, but at equal rates, so concentrations stay constant.
Problem 2
At dynamic equilibrium, the concentrations of reactants and products…
- drop to zero
- keep rising
- are always equal
- stay constant
Answer and explanation
stay constant
At equilibrium the forward and reverse rates are equal, so the concentrations stay constant — though not necessarily equal.