A reversible reaction can proceed in both the forward and reverse directions. At dynamic equilibrium, the rates of the forward and reverse reactions are equal - but both reactions are still occurring.
Conditions for Dynamic Equilibrium
- The system must be closed (no substances enter or leave)
- Rate of forward reaction = rate of reverse reaction
- Macroscopic properties (concentrations, colour, pressure) remain constant
- At the molecular level, both reactions continue
Reaching Dynamic Equilibrium
At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction, but the reactions have not stopped.
Think About It
If you open a bottle of fizzy water, is the CO₂(aq) ⇌ CO₂(g) system at equilibrium?
No - the system is no longer closed. CO₂ gas escapes, so the forward reaction is favoured and the position shifts to the right until all dissolved CO₂ has escaped.
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