When 4 kg moles of an ideal gas undergo free expansion into a vacuum, the total work performed is_________________?
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Answer: C. 0
Explanation
Free expansion of an ideal gas into a vacuum occurs against zero opposing external pressure. Mechanical work done by a system is calculated by multiplying external pressure by volume change. Since the external pressure is zero, the total work performed during the expansion is zero. Joule performed famous free expansion experiments demonstrating that internal energy remains constant. An ideal gas has no intermolecular forces, so its temperature does not change during free expansion. Thermodynamic processes in vacuums represent classic irreversible expansions in engineering.
Understanding work calculations in thermodynamics is vital for analyzing power cycles and turbines. Vacuum systems are widely used in chemical processing and semiconductor manufacturing industries. Free expansion illustrates why work is a path function dependent on external resistive forces. Four Joules incorrectly assigns a nonzero numerical work value to an unresisted expansion. Infinity is an absurd mathematical limit that does not apply to bounded thermodynamic systems. Eight Joules is another arbitrary nonzero value that contradicts the definition of vacuum expansion.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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