  According to contemporary views, equilibrium constant is relevant only to
true thermodynamic equilibria in isolated systems with one chemical reaction.
The paper presents a novel formula that ties-up equilibrium constant and
chemical system composition at any state, isolated or open as well. Extending
the logarithmic logistic map of the Discrete Thermodynamics of Chemical
Equilibria, this formula maps the system population at isolated equilibrium
into the population at any open equilibrium at p,T=const, using equilibrium
constant as a measure. Real chemical systems comprise multiple subsystems;
given the resources are limited, joint solution to the set of such expressions,
each relevant to a specific subsystem, gives equilibrium composition for each
of them. This result means a fundamental break through in the open systems
thermodynamics and leads to formerly unknown opportunities in the analysis of
real chemical objects.
