Second Law of Thermodynamics

SECOND LAW OF THERMODYNAMICS

The following are all Equivalent statements of the Second Law:

1. Heat Energy always flows from Hot to Cold.

2. The Entropy of an isolated system never spontaneously decreases. The Entropy of an isolated system either increases or at best remains constant.

3. The Maximum Efficiency of any Heat Engine operating between two heat Reservoirs (with temperatures T_hhot and T_ccold) is equal to that of a Carnot heat engine.

4. The order or complexity of an isolated system never spontaneously moves in the direction of more order or complexity, even if some subpart of the system becomes more ordered. If Ω is equal to the total number of states accessible to the system, then

5. The direction of a spontaneous change for an isolated system is from an arrangement of lesser probability to an arrangement of greater probability.

Corollaries to the Second Law

	The following are all Equivalent statements of the Second Law:
1.	Heat Energy always flows from Hot to Cold.


2.	The Entropy of an isolated system never spontaneously decreases. The Entropy of an isolated system either increases or at best remains constant.


3.	The Maximum Efficiency of any Heat Engine operating between two heat Reservoirs (with temperatures T_hhot and T_ccold) is equal to that of a Carnot heat engine.


4.	The order or complexity of an isolated system never spontaneously moves in the direction of more order or complexity, even if some subpart of the system becomes more ordered. If Ω is equal to the total number of states accessible to the system, then


5.	The direction of a spontaneous change for an isolated system is from an arrangement of lesser probability to an arrangement of greater probability.