01
First Law
ΔU = Q - W
The first law expresses conservation of energy for thermodynamic processes, with sign conventions depending on how work is defined.
02
Second Law
ΔS_total ≥ 0
The second law introduces the directionality of thermodynamic processes through entropy and limits the efficiency of heat engines.
03
Third Law
The third law describes the limiting behavior of entropy as temperature approaches absolute zero for systems satisfying its standard assumptions.