Question

Question: Using the postulates of the kinetic molecular theory, explain why a gas uniformly fills a container of any shape.

Short answer

The first postulate of the kinetic molecular theory suggests that gas molecules collide with walls of a container and fills a container of any shape.

Step-by-step solution

Concept Introduction

The following postulates, or assumptions, underpin the kinetic molecular theory.

• Gases consist of a vast number of particles, which acts like hard, spherical objects moving in a random manner.
• These particles travel in a straight line until they clash with another particle or a container's walls.
• The space between the particles is substantially smaller than the size of the particles. As a result, the majority of a gas's volume is empty space.
• No attraction exists between gas particles or between the particles and a container's walls.
• When a gas particle collides with another particle or with the ground, none of its energy is wasted.

Postulate of Kinetic Molecular Theory

From the first postulate of the kinetic molecular theory, gas molecules are in continuous motion, traveling in straight lines and changing directions only when they collide with other molecules or with the walls of a container. Gas molecules in a container constantly collide with each other and with the walls of a container, due to which they change their direction, and these collisions are completely random due to which the gas molecules distribute uniformly. It can also fill a container of any shape. Therefore, gases fill a container completely.