Kinetic molecular theory

Kinetic Molecular Theory (KMT)

A simplified model that describes the behavior of ideal gases based on a series of postulates about the nature of the gas particles.

KMT Postulate 1 (Particle Size)

The size of gas particles is so small compared with the distances between them that the volume of the particles is negligible (ignored for an "ideal gas").

KMT Postulate 2 (Particle Motion)

Gas particles are in continuous, random motion, traveling in straight lines until they collide.

KMT Postulate 3 (Interparticle Forces)

Particles are assumed to have no attractive or repulsive forces between them, meaning IMFs are ignored (for an "ideal gas").

KMT Postulate 4 (Kinetic Energy and Temperature)

The average kinetic energy of a sample of a gas is proportional to the Kelvin temperature of the gas.

Kinetic Energy Equation

KE 1/2mv^2 (m is mass in kg; v is velocity in m/s; KE is in Joules).

Average Kinetic Energy and Temperature

The Kelvin temperature of a sample of matter is proportional to the average kinetic energy of the particles in the sample.

Maxwell-Boltzmann Distribution

A graphical representation that shows the distribution of the kinetic energies (or velocities) of the particles at a given temperature.

Effect of Increasing Temperature (Maxwell-Boltzmann)

Increasing the temperature shifts the Maxwell-Boltzmann distribution curve to the right, showing that the average kinetic energy and average speed of the particles increase.

Graham's Law of Effusion

The rate at which a gas effuses (diffuses through a small hole) is inversely related to the square root of its molar mass.

Graham's Law (Formula)

Rate 1/Rate 2 = sqrt(Molar mass 2/Molar mass 1).

Effusion

The ability of a gas to diffuse through a small hole.