Entropy change of an incompressible substance
For most liquids and all solids, the density is not changed as pressure changes, that is, dv=0. Gibbsian equation states that Tds=du+pdv=du, du=CdT, for an incompressible substance Cp=Cv=C is a function of temperature only. Therefore, ds=du/T=CdT/T
- Specific heats for some common liquids and solids can be found in thermodynamic tables such as Table A-14 to A-19