Difference Between Effusion and Diffusion

Effusion and diffusion are two commonly used terms in chemistry and these two terms are nothing but two different properties of gases. However, while studying the terms, it can get quite confusing for many who are just starting to learn about gases. They might sound similar but diffusion and effusion are entirely different terms. They mean different things and they cannot be used interchangeably.

Diffusion is defined as the ability of gases to mix with each other without requiring bulk motion. Effusion is also the ability of a gas to escape or travel through a small hole with a small aperture and from a place of high concentration to low concentration.

In essence, diffusion and effusion are processes that happen everyday in our lives. Diffusion normally occurs inside the body where exchanges of nutrients, energy and oxygen happen within our body. That being said, It is quite important to know the differences between effusion and diffusion.

Difference Between Effusion and Diffusion

The main difference between effusion and diffusion is the barrier that either exists or is absent when a certain volume of gas moves from one place to another space. However, we will look at some of the main differences below.

Difference Between Effusion and Diffusion



Effusion is said to occur when gas molecules escape through a pinhole into a vacuum.

During diffusion one gas mixes with another usually by thermal random motion resulting in the collision between each other while releasing molecular energy.

Effusion in simple terms is the ability of gas to travel through a small opening.

Diffusion is the ability of gases to mix with each other usually in the absence of a barrier.

Effusion occurs when the size or aperture of the hole is smaller than the mean free path of the molecules.

Diffusion happens when there are no holes or if holes in the barrier are larger than the mean free path.

During effusion particles move faster than diffusion because there is no collision between molecules.

Diffusion rate is limited by the size and kinetic energy of the other particles.

Effusion occurs or is facilitated by a difference of pressures.

Diffusion occurs due to difference in concentrations.

These are some of the differences between effusion and diffusion. To know more about and other chemistry topics you can keep visiting BYJU’s or download our app for interesting content and learning experience.

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