Question

Given the system at chemical equilibrium: 2 O3 (g) <-> 3 O2 (g). The concentration of O3 and O2 must be:
a) Constant
b)Equal
c)Increasing
d)Decreasing

Answer 1

when a system is at equilibrium it means that the concentrations of each of the species are not changing (the rates of the forward and backward reactions are the same). This doesn't mean that their concentrations are equal though.