Adiabatic process: a process where no heat is gained or lost. it is my understanding, however, that this is a hypothetical system. There is no insulator on earth good enough to allow this system to exist, except to approximations. So, what happens is you have a system where whatever is inside the system is held at the same temperature as the surrounding environment? Is that considered adiabatic? Now, what if you add energy to the system, how do you maintain an adiabatic system? Do you alleviate the pressure? Isochoric process: a process where the volume doesn't change. no work can be done on an isochoric system because the volume is not allowed to change. Is this why the thermodynamic equation describing change in energy cannot be based solely upon work but, rather, it has to include a term for heat transfer? Isobaric process: a process where pressure remains constant. In reality, is this system only possible if you adjust temperature and volume in equal proportion, so as to avoid increases or decreases in pressure? Is there another scenario where an isobaric process is possible? Isothermal process: a process where temperature does not change. Does an isothermal system have to be adiabatic? Or does heat flux make the system not adiabatic? In what system do you add energy and keep temperature the same? Thank you.