What does kinetic molecular theory describe?

Kinetic molecular theory specifically focuses on the behavior of gases, describing how gas particles are in a state of constant, random motion. It posits that the temperature of a gas is directly related to the average kinetic energy of its particles. This theory helps explain various gas behaviors, such as pressure, volume, and temperature relationships (as described by the ideal gas law) and phenomena such as diffusion and effusion.

In this context, the key point of kinetic molecular theory is that gases consist of small particles that are in constant motion and that these particles collide elastically with one another and the walls of their container. This understanding is crucial in explaining why gases can expand to fill their containers and why changes in temperature and pressure can significantly impact the properties of a gas.

The other options do not align with the core principles of kinetic molecular theory, as they address the behaviors of liquids, solids, and plasma under different conditions, which are governed by different sets of principles that account for intermolecular forces and the structure of matter.