K

Kinetic Molecular Theory

KE_avg = (3/2)kT; PV = nRT
Quick Reference
Formula / NotationKE_avg = (3/2)kT; PV = nRT
Also Known AsKinetic theory of gases, KMT, molecular kinetic theory, ideal gas kinetic theory

What is Kinetic Molecular Theory?

A model that explains the behavior of gases by describing gas molecules as small particles in constant random motion with elastic collisions. The theory explains gas laws, temperature as average kinetic energy, and diffusion. It forms the basis for understanding gas behavior at the molecular level.

Formula & Notation

KE_avg = (3/2)kT; PV = nRT

Other Names / Synonyms: Kinetic theory of gases, KMT, molecular kinetic theory, ideal gas kinetic theory

Properties & Characteristics

The Kinetic Molecular Theory (KMT) of gases explains the macroscopic properties of gases from the motion of molecules at the molecular level. Key postulates: (1) Gas molecules are in constant, random motion; (2) Molecular volume is negligible compared to container volume; (3) No intermolecular forces (ideal); (4) Collisions are perfectly elastic; (5) Average kinetic energy is proportional to absolute temperature: KE_avg = (3/2)kT. KMT derives the ideal gas law and explains gas diffusion, effusion, and pressure.

Uses & Applications

KMT is used to derive: the ideal gas law (PV = nRT), Graham's law of effusion, Maxwell-Boltzmann speed distribution, mean free path, and collision frequency. It explains why gases expand to fill containers, why pressure increases with temperature (more energetic collisions), and why diffusion is faster at higher temperatures.

Safety Information

KMT assumptions (no intermolecular forces, negligible volume) fail at high pressures and low temperatures, where real gas deviations lead to unexpected condensation or pressure behaviour. Process safety calculations must use real gas equations of state for conditions near the critical point.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Kinetic Molecular Theory
Formula KE_avg = (3/2)kT; PV = nRT
Synonyms Kinetic theory of gases, KMT, molecular kinetic theory, ideal gas kinetic theory

Frequently Asked Questions

A model that explains the behavior of gases by describing gas molecules as small particles in constant random motion with elastic collisions. The theory explains gas laws, temperature as average kinetic energy, and diffusion. It forms the basis for understanding gas behavior at the molecular level.

More "K" Terms

View all "K" terms →
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z