Effusion

Definition

Effusion is the process by which gas particles pass through a tiny opening from one container to another. It occurs when gas molecules escape from a container into a vacuum or less pressurized area through a small hole.

5 Must Know Facts For Your Next Test

1. Effusion rate is inversely proportional to the square root of the molar mass of the gas, according to Graham's law.
2. Graham's law of effusion mathematically states that $\text{rate}_1 / \text{rate}_2 = \sqrt{M_2 / M_1}$, where $\text{rate}_1$ and $\text{rate}_2$ are the effusion rates of gases 1 and 2, and $M_1$ and $M_2$ are their molar masses.
3. Lighter gases effuse faster than heavier gases due to their lower molar mass.
4. Effusion differs from diffusion in that effusion involves movement through a small hole, whereas diffusion involves spreading throughout a space.
5. Real-life applications of effusion include separation of isotopes in nuclear processes and leakage detection in containers.

Review Questions

• What is Graham's law of effusion and how is it mathematically expressed?
• How does the molar mass of a gas affect its rate of effusion?
• What is the primary difference between effusion and diffusion?

Related terms

Diffusion: The process by which gas molecules spread out in response to a concentration gradient within an enclosed space.

Graham's Law: A law stating that the rate of effusion (or diffusion) of a gas is inversely proportional to the square root of its molar mass.

Molar Mass: The mass of one mole of a substance, typically measured in grams per mole (g/mol), which influences properties like density and rate of effusion.