Final answer:
Gases diffuse because gas particles move from areas of higher concentration to lower concentration until evenly distributed, influenced by pressure and temperature.
Step-by-step explanation:
The diffusion of gases happens because gas particles are in constant motion and tend to move from areas of higher concentration to areas of lower concentration. This movement continues until the concentrations are equal in every part of the container, a process driven by the inherent properties of gases. The random, constant motion of gas particles, paired with the elastic collisions between them and the walls of the container, ensures that when gases like helium (He), argon (Ar), hydrogen (H₂), or oxygen (O₂) are placed in a container, they will diffuse and eventually become uniformly dispersed. The pressure and temperature also influence the rate of diffusion as they affect the average speed of gas particles.