How do we know the internal energy of a system is always zero for a cyclic process?
(2 students) The internal energy of the system is not zero. The net change in internal energy is zero since the system returns to the same thermodynamic state (the definition of a cyclic process) and internal energy is a property and therefore only a function of the state of the system. So for a cyclic process, Q=W. A little unclear on why DU is path independent and Q & W are path dependent. (2 students) The above should address the first part. Relative to why Q and W depend on path — it is just a reflection of the way things work in the world around us. All it says is that the net energy change of a system must balance the sum of that which crosses the system boundaries (Q-W); beyond that, some processes (paths) lead to more or less energy change, more or less energy transferred as heat at the boundary and more or less energy transferred as work at the boundary. Hence they are path dependent. 7) In a cyclic process, how is the surrounding affected? (2 students) Typically for heat eng
