How is a closed thermodynamic system defined_________________________?
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Answer: A. mass does not cross boundaries of the system, though energy may do so
Explanation
In a closed thermodynamic system, mass does not cross boundaries of the system. However, energy in the form of heat or work may freely cross the system boundaries. This distinction separates closed systems from open systems and isolated systems in thermodynamics. Thermodynamic systems are classified by how mass and energy interact across their boundary walls. A closed system maintains a fixed total mass while allowing thermal or mechanical energy transfer. Pistons sealing gas inside a cylinder represent classic examples of closed thermodynamic systems.
Thermodynamic cycle analysis for reciprocating engines treats the working fluid as a closed system. First law energy balances for closed systems account strictly for heat added and work done. Chemical engineers use closed system models to analyze batch reactor energy transformations. Option B describes a system allowing mass entry while blocking energy, which does not exist physically. Option C describes an isolated system where neither mass nor energy crosses boundaries. Option D describes an open system where both mass and energy cross the control boundaries.
- Subject
- Engineering
- Category
- Mechanical Engineering
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- —
- Difficulty
- medium
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