01Dynamic, not stopped
In a closed system, a reversible reaction reaches equilibrium when the forward and reverse rates are equal. Both reactions keep happening; concentrations stop changing.
Equal rates do not mean equal concentrations.
02Notebook box
On a concentration–time graph, equilibrium = where lines go flat.
Worked example: At equilibrium [A] = 0.2 M, [B] = 0.8 M. Are rates equal? Yes — concentrations differ, rates match.