Define a system and simplify the energy balance for each of the following cases. Clearly define the system and state whether the system is open or closed and justify simplifications you have applied. State, when possible, if the nonzero heat and work terms are positive or negative.

a$.$ Flue gas is continuously fed to a cryogenic cooling installation to solidify and separate the $C{O}_2$ as a means of a $C{O}_2$ capture process.

b$.$ A batch reactor producing acetaminophen from p$-$aminophenol and acetic anhydride, which is an endothermic reaction, operating at constant temperature.

c$.$ Water is pumped up from Lake Louise $($the lake$)$ to the ski resort to be used in snow cannons to produce snow. You can assume that the pipe has a constant diameter and that the pipes are well$-$insulated.