Dynamic equilibrium
Dynamic equilibrium
- A reversible reaction can go both ways ($\rightleftharpoons$).
- In a closed system it reaches a dynamic equilibrium.
- At equilibrium nothing appears to change — but both reactions are still going.
Practice
A reversible reaction is one that:
A reversible reaction (⇌) can form products and turn them back into reactants.
Practice
A closed system is needed to reach equilibrium.
If the system were open, products could escape and the forward and reverse rates could never balance.
What equilibrium means
- At dynamic equilibrium:
- the forward rate equals the reverse rate, and
- the concentrations of reactants and products stay constant.
- It is dynamic because both reactions are still happening — they just cancel out.
- A closed system is needed, or products would escape and equilibrium could never be reached.
Practice
At dynamic equilibrium:
The two rates are equal, so the concentrations of reactants and products no longer change.
Practice
Why is it called a "dynamic" equilibrium?
Both forward and reverse reactions continue at equal rates, so they balance — dynamic, not static.
You've got it
Key idea
- a reversible reaction ($\rightleftharpoons$) goes both ways
- dynamic equilibrium: forward rate = reverse rate, concentrations constant
- both reactions still happen (dynamic); needs a closed system