How is the reaction rate related to equilibrium?
1 Answer
We need to distinguish between static and dynamic equilibrium.
The common equilibrium you see in chemistry is dynamic equilibrium:
The rate of the forward and reverse reactions are equal, thus resulting in no net change in the concentrations of products or reactants.
Example:
#"H"_2(g) + "I"_2(g) stackrel(k_1)(rightleftharpoons) 2"HI"(g)#
#color(white)(aaaaaaaaaaaa)^(k_(-1))#
where#k_(1) = k_(-1)# .
The less common "equilibrium" is static equilibrium:
A reaction has not occurred or has previously finished, yet no motion occurs at that time. The rate of a reaction in either direction at static equilibrium is
NOTE: this does NOT necessarily mean that the concentrations of products is equal to the concentrations of reactants.
Example:
#"C" ("graphite") -> "C" ("diamond") rightleftharpoons "C" ("diamond")# Here,
#["C" ("diamond")] > 0# , but#["C" ("graphite")] = 0# .
