Graham's Law of Diffusion and Effusion

Introduction

• Thomas Graham: Scottish chemist, 19th century.
• Graham's law describes the relationship between the rate of diffusion of a gas and its molecular weight.
• Applies to both diffusion and effusion processes.

Key Concepts

Diffusion

• Definition: The process by which particles move from an area of high concentration to an area of lower concentration until equilibrium is reached.
• Equilibrium: State where the concentration of particles is the same throughout the space.

Graham's Law Basics

• Inverse Proportionality: Rate of diffusion ∝ 1 / √(Molecular Weight).
• Lighter gas molecules diffuse faster.
• Mathematically: (Rate1 / Rate2) = √(M2 / M1)
  • Rate1: Rate of diffusion of gas 1.
  • Rate2: Rate of diffusion of gas 2.
  • M1: Molar mass of gas 1.
  • M2: Molar mass of gas 2.

Solubility Coefficient

• Definition: Measure of how easily a gas dissolves in a liquid.
• Higher solubility = slower diffusion.
• Gas molecules are more likely to dissolve in liquid rather than move through a membrane if solubility is high.

Additional Insights

• Ideal Conditions: Graham's law assumes non-interacting gas molecules and no temperature or pressure differences.
• Real Conditions: Factors like temperature, pressure, and the presence of other molecules can affect diffusion rates.

Applications

• Atmospheric Chemistry: Understanding gas behavior in the atmosphere.
• Human Body: Study of gas behavior in biological systems.
• Industrial Processes: Diffusion of gases in various industrial applications.

Conclusion

• Graham's law is useful for understanding gas diffusion despite its limitations.
• Simple yet powerful for a wide range of contexts.

Outro

• Reminder that the video is for informational purposes and the creators are not doctors.
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