A puff of gas is released into one corner of an otherwise empty vacuum chamber. According to the source, what happens to the gas over time, and does the reverse ever occur spontaneously?
AThe gas fills the chamber and never regroups in the corner
BThe gas stays fixed in the corner unless heated from outside
CThe gas spreads out, then regularly returns to the corner
DThe gas splits evenly between the corner and the center
Answer & Solution
Correct answer: A. The gas fills the chamber and never regroups in the corner
1. Once released, the gas molecules move randomly and spread out until they occupy the entire chamber uniformly.
2. Although the random motion of the molecules could in principle take them all back to the corner, this is never observed to happen.
3. This rules out option C, which claims a regular spontaneous return, and option B, which wrongly claims the gas stays put without spreading at all.
4. The gas does not settle into an even split between the corner and the center either; it disperses throughout the whole available volume, ruling out option D.
_Source: OpenStax College Physics (CC BY 4.0), Ch 15 "Thermodynamics", section 15.3 Introduction to the Second Law of Thermodynamics: Heat Engines and Their Efficiency_
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