In a 350 ton R-11 chiller at 0 psig, what is the approximate amount of vapor that will remain after all liquid is removed?

In the context of refrigerant R-11 and the operation of a chiller, understanding the behavior of refrigerants in different phases is crucial. After all liquid refrigerant is removed from a system, the remaining vapor is significantly influenced by the properties of the refrigerant at particular pressures and temperatures.

For R-11 at 0 psig, it is important to recognize that this refrigerant has specific characteristics defined by its pressure-temperature relationship. At 0 psig, R-11 vapor will be at a low temperature point but still exists as vapor at this pressure, which means there is a notable volume of vapor that remains in the system after all the liquid is extracted.

The approximate amount of vapor that remains—about 100 pounds—stems from considerations of the total charge of the system and characteristics of R-11. This value is also consistent with the estimated quantities generally found in similar systems based on their capacity and the refrigerant type.

Hence, stating that around 100 pounds of vapor remains after liquid removal aligns with the expected behavior of R-11, reflecting both its physical properties and the system design in which it operates. This is why the choice indicating 100 pounds is considered the correct answer.