If we add more of one component, or remove some of another, either
the forward or the reverse reaction will be favored; the separate
concentrations will adjust, and when equilibrium is restored after
the disturbance, the Keq, ratio will be the same as before. Keq
varies with temperature, but at a given temperature it is entirely
independent of the individual concentrations of reactants and products.
The illustrations on these pages emphasize the fact that the conditions
of equilibrium are the same no matter from which side they are approached.
Starting from either pure
and or pure
HI, the reaction eventually will reach equilibrium at the same ratio
of products to reactants given by Keq.
In the top picture, the same tank is filled with 2 moles of HI.
After a time, measurable quantities of
present (center). When equilibrium is reached and the composition
of the tank becomes constant, the same equilibrium concentrations
are observed as before, 0.22 mole each of
and , and
1.56 moles of HI.
The equilibrium conditions are the same, no matter what the direction