Originally posted by Proteios
hmmm lets try again.
Reactions with +ve DGs dont happen is not true. They happen but you have to put energy in.
all reactions are microscopically reversible.
The equilibirium constant is just a numerical experssion for the populations of two states (defined by the difference in energy of the two states and
energy available to the molecules (typically a boltzman distrubtion)).
If DG is very large compared to the typical energy avail. to the molecules, the reaction is typically termed irreversible (H2 + O2 for instance).
However even here equilibrium constant can be defined, its just from a practical standpoint its kinda pointless. |