List of top Thermodynamics Questions on Properties of pure substances

Four different Entropy (S) - Temperature (T) diagrams, representing liquid to vapour phase transition process of a pure substance in a closed system under constant pressure are shown. The diagram, which correctly represents the process, is: 
 

For the Refrigerant R-134 (at 1 MPa and 50°C), the difference between the specific volume computed by assuming it to be an ideal gas and its actual specific volume is: \( v_{\text{ideal}} - v_{\text{actual}} = 4.529 \times 10^{-3} \, \text{m}^3/\text{kg} \). If the compressibility factor associated with this state is \( Z = 0.84 \), then \( v_{\text{com}} - v_{\text{actual}} = \underline{\hspace{2cm}} \times 10^{-3} \, \text{m}^3/\text{kg} \) (3 decimal places).

A rigid tank contains 1.0 kg of pure water consisting of liquid and vapour phases in equilibrium at 10 bar. If the liquid and vapour phase each occupies one half of the volume of the tank, then the net enthalpy of the contents of the tank is \(\underline{\hspace{2cm}}\) kJ (1 decimal place).
The liquid phase of a pure substance is termed as \(\underline{\hspace{2cm}}\), if its temperature is lower than the saturation temperature corresponding to its pressure \(P\).