Final answer:
Distillation cannot occur in a closed system because the process requires the transfer of matter, which is not possible in a closed system where only energy can be exchanged. The distillation setup involves evaporating a substance and then condensing it in a separate location, making an open or partially open system necessary.
Step-by-step explanation:
Distillation cannot take place in a closed system because the process requires the transfer of matter, specifically the removal of the distilled substance from the system. In distillation, components of a mixture are separated based on differences in volatility by evaporating and then condensing the vapor.
This process necessitates that the vapor can leave the system where it was evaporated, enter a condenser, and be collected elsewhere. For example, the parts of a distillation setup typically include a heat source such as a Bunsen burner to evaporate salt water in a distilling flask, a condenser to cool down and condense the vapor, and a receiving flask for the collection of pure water.
A closed system, however, allows for the exchange of energy but not matter with its surroundings. Thus, a distillation process, which needs to transport matter (the condensate) out of the system, cannot be conducted in a perfectly closed environment, as the entire concept of distillation involves the dispersal and collection of vapor in a new location.
The dynamic equilibrium between liquid and vapor that would be established in a closed system with a fixed volume prevents the successful separation and removal of the distilled product. Therefore, distillation is conducted in an open or partially open system (distillation apparatus), allowing for the necessary phase transitions and transport of matter.