2013-2-27 Phase Pure Substance 3-1 State Principle for Simple Compressible Systems ar imple co The intensive state of a simple compressible system at equilibrium is described by its intensive properties,including temperature,pressure, specific volume,density,specific internal energy, and specific enthalpy. Properties such as velocity and elevation are excluded because their values depend on arbitrary datum choices.such as zero values at the surface of the earth.For the state principle,these properties are not relevant. 3-8 4 2013-2-27 4 Phase & Pure Substance 3-7 State Principle for Simple Compressible Systems ►Systems of commonly encountered pure substances are called simple compressible systems. These substances include those in appendix tables A-2 through A-18, A-22, and A-23. ►The intensive state of a simple compressible system at equilibrium is described by its intensive properties, including temperature, pressure, specific volume, density, specific internal energy, and specific enthalpy. ►Properties such as velocity and elevation are excluded because their values depend on arbitrary datum choices, such as zero values at the surface of the earth. For the state principle, these properties are not relevant. 3-8