
Equilibrium:
Today we derived an expression that defines the composition of any
reaction at equilibrium, the point were the system has minimized its
potential energy (i.e. free energy). This expression is a
ratio with products (raised to their stoichiometric coefficients) in
the numerator and reactants (raised to their stoichiometric
coefficients) in the denominator. This ratio, the equilibrium
constant K, tells us how much of each species at
equilibrium. More importantly, because we can calculate K
from standard reaction free energies, we can determine the value of
K, and thus the composition of the reaction at equilibrium,
without actually having to do an experiment.

