PROBABILITY - predictor of most stable state
WHY DO PROCESSES with ? H = 0 occur ?
Consider expansion of gases to equal pressure:
This is spontaneous because the final state,
with equal # molecules in each flask,
is much more probable than the initial state,
with all molecules in flask 1, none in flask 2
SYSTEM CHANGES to state of HIGHER PROBABILITY
For entropy-driven reactions - the more RANDOM state.