Concept:The simple gas laws (Boyle's, Charles's, Gay-Lussac's) explore the relationships between Pressure (P), Volume (V), and Temperature (T) within a closed system.
Solution:- A "closed system" strictly implies that gas is neither allowed to enter nor escape the container.
- Therefore, the mass, or the number of moles (n), remains inherently constant across all these foundational gas laws.
- For example: Boyle's law requires constant \( T \) and \( n \). Charles's law requires constant \( P \) and \( n \). In all cases, \( n \) must be locked to observe the P-V-T dynamics.
Why other options are incorrect:- Options A, B, & C: While one of these variables is held constant in specific laws (e.g., T in Boyle's, P in Charles's), only the number of moles (mass) is held constant universally across all these standard simple gas laws.
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