WHAT about EXOTHERMIC REACTIONS ?
Consider 2 H2 (g) + O2 (g) ? 2 H2O (l)
- final state (liquid) is MUCH MORE ORDERED
(less random arrangement) than initial state (2 gases)
- BUT PROBABILITY of final state is higher when one
considers change in the surroundings. WHY ?
- Heat evolved increases motion of molecules in the surroundings
Increased disorder of surroundings
decreased disorder of system
MUST consider change in disorder in
BOTH SYSTEM and SURROUNDINGS
to predict DIRECTION of SPONTANEITY