The problem analysis and solution technique is contained within the framework of the following set of questions that must be answered in the process of an orderly solution of a thermodynamic problem:
1. What is the control mass or control volume? Is it useful, or necessary, to choose more than one? It may be helpful to draw a sketch of the system at this point, illustrating all heat and work flows, and indicating forces such as external pressures and gravitation.
2. What is known about the initial state (i.e., what properties are known)?
3. What is known about the final state?
4. What is known about the process that takes place? Is anything constant or zero? Is there some known functional relation between two properties?
5. Is it helpful to draw a diagram of the information in steps 2 to 4 (for example, a T−v or P−v diagram)?
6. What is the thermodynamic model for the behavior of the substance (for example, steam tables, ideal gas, etc...)?
7. What is the analysis of the problem (i.e., should control surfaces for various work modes be examined or should the first law or conservation of mass be used)?
8. What is the solution technique?
When faced with a new and unfamiliar problem, one should always at least think through this set of questions to develop the ability to solve more challenging problems.