PROPERTY DIAGRAMS AND STEAM TABLESThermodynamicsTemperature-Entropy (T-s) DiagramA  T-s  diagram  is  the  type  of  diagram  most  frequently  used  to  analyze  energy  transfer  systemcycles.   This is because the work done by or on the system and the heat added to or removedfrom the system can be visualized on the T-s diagram.   By the definition of entropy, the heattransferred to or from a system equals the area under the T-s curve of the process.   Figure 13 isthe T-s diagram for pure water.   A T-s diagram can be constructed for any pure substance.   Itexhibits the same features as P-u  diagrams.Figure 13   T-s Diagram for WaterIn the liquid-vapor region in Figure 13, water and steam exist together.   For example, at pointA, water with an entropy (s_f) given by point B, exists together with steam with an entropy (s_g)given by point C.  The quality of the mixture at any point in the liquid-vapor region can be found by .s = xs_g  + (1 - x)s