A chemical equilibrium: A reversible chemical reaction can be at equilibrium under certain conditions: U正=D逆≠0 The basic features of chemical equilibrium: (1)the composition of an equilibrium mixture undergoes no further change with time. (2)chemical equilibria are dynamic. (3)the equilibrium composition is independent of the path of approach A chemical equilibrium：  正 = 逆  0 A reversible chemical reaction can be at equilibrium under certain conditions: The basic features of chemical equilibrium： (1) the composition of an equilibrium mixture undergoes no further change with time. (2) chemical equilibria are dynamic. (3) the equilibrium composition is independent of the path of approach