Final answer:
The equation dEsystem = dq - (psys - psurr)dV is not the correct expression for the change in system's energy. The piston's kinetic energy does not necessarily account for the net work in this scenario.
Step-by-step explanation:
The work-energy theorem states that the net work done on a system is equal to the change in its kinetic energy. In the given scenario, the work done by the system on the piston is Fsys ⋅ (ds), while the work done by the surroundings on the piston is Fsur ⋅ (-ds). The net work is stored in the piston as its kinetic energy.
The equation dEsystem = dq - (psys - psurr)dV is not the correct expression for the change in system's energy. It seems to be a misconception. The relationship between work, forces, and energy changes is more complex than indicated, as mentioned in option C.
Therefore, the correct option to choose is C. The piston's kinetic energy does not necessarily account for the net work in this scenario.