A gas that is described perfectly by the kinetic molecular theory is called a(n)?

• A. Real Gas
• B. Monatomic Gas
• C. Ideal Gas
• D. Diatomic Gas

Answer: (C)

Ideal gas behavior is described by the kinetic molecular theory, which imagines gas particles as point particles with negligible volume, no attractive or repulsive forces between them except during elastic collisions, and whose average kinetic energy depends only on temperature. A gas that follows these assumptions exactly is called an ideal gas. The ideal-gas model leads to the simple PV=nRT relationship and to gas properties that depend only on temperature, pressure, and amount, not on the particular identity of the molecules. In reality, no gas is perfect; deviations arise when particle size becomes significant or intermolecular forces matter, especially at high pressure or low temperature, which is why real gases require corrections like the van der Waals equation. The terms monatomic or diatomic describe how many atoms are in a molecule rather than how closely the gas follows the kinetic molecular theory, so they do not by themselves define the idealized behavior.