Explain why a closed system can reach dynamic equilibrium while an open system cannot.

A closed system has no exchange of matter with its surroundings, so the amounts of reactants and products can change only by the forward and reverse reactions occurringwithin the system. As the reactions proceed, the concentrations of reactants and products adjust until the rate of the forward reaction equals the rate of the reverse reaction, givinga constant concentration of each species – dynamicequilibrium. In an open system, matter can enter or leave, so the concentrations of reactants or products can continue to change and the rates of the forward and reverse reactions will never become equal, preventingthe establishment of a true equilibrium.

This answer demonstrates understandingof the definition of a closed system, the concept of dynamicequilibrium, and the reason why open systems cannot maintain equal forward and reverse rates. It tests the student’s ability to distinguish system boundaries and apply the concept to equilibrium behaviour.