Final answer:
Effusion is the escape of gases through tiny openings in a container, where lighter gases effuse faster than heavier gases, according to Graham's law of effusion. Diffusion is the movement of gases from a region of higher concentration to one of lower concentration. When gases mix, they form a solution with increased entropy (disorder).
Step-by-step explanation:
When a mixture of gases is placed in a container with porous walls, the phenomena of effusion and diffusion occur. Effusion is when gases escape through tiny openings in a container, often resulting in a lighter gas effusing more quickly than a heavier gas. This is because the rate of effusion is inversely proportional to the square root of the mass of its particles, as described by Graham's law of effusion. In addition, gases will also diffuse, mixing from areas of higher concentration to areas of lower concentration. When two different gases are allowed to mix, they form a solution favored by the increase in entropy, which represents the increased disorder compared to the separate gases.