Sample Problems on Fick’s Law of Diffusion
Problem 1: A membrane has a diffusion coefficient (D) of 1 × 10−5cm2/s. The concentration gradient (dx/dc) across the membrane is 2 × 10−3mol / cm4, and the cross-sectional area (A) is 2cm2 . Calculate the diffusion flux (J).
Solution:
Given: D = 1 × 10−5cm2/s
dx/dc = 2 × 10−3mol / cm4
and A is 2 cm2
J = −D⋅A⋅ dx/dc
⇒ J = −(1 × 10−5cm2/s) × (2cm2) × (2 ×10−3mol/cm4)
⇒ J = −4 × 10−8 mol/s
The negative sign indicates that the substance is moving in the direction of decreasing concentration.
Problem 2: Suppose a gas with a diffusion coefficient (D) of 4 × 10−6 m2/s is diffusing through a sheet of material with a thickness (x) of 0.02m. The concentration gradient (dx/dc ) across the sheet is 2 mol/m4, and the area (A) is 0.1 m2. Calculate the diffusion flux (J).
Solution:
Given: D = 4 × 10−6 m2/s
dx/dc = 2 mol/m4
and A is 0.1 m2
J = −D⋅A⋅ dx/dc
⇒ J = −(4 ×10−6m2/s) × (0.1 m2) × (2mol/m4)
⇒ J = −8 × 10−7mol/s
The negative sign indicates the direction of decreasing concentration.
Fick’s Law of Diffusion
Fick’s Law of Diffusion is an important principle in physics and chemistry. This law describes the rate at which particles (such as molecules, atoms, or ions) diffuse through a medium. It was formulated by Adolf Fick, a German physiologist, in the 19th century. It helps us understand how molecules move and diffuse in space, and in which direction they migrate.
In simple words, Fick’s law states that molecules diffuse in space from a point of higher concentration to a point of lower concentration. In this article, we will learn about all related topics to Fick’s Law of Diffusion. This article includes both the first and second laws along with their derivations. Additionally, we will discuss some common applications of this law.
Table of Content
- What is Diffusion?
- What is Fick’s Law of Diffusion?
- Fick’s Law of Diffusion Formula
- Fick’s First Law of Diffusion
- Fick’s Second Law of Diffusion
- Application of Fick’s Law of Diffusion
- Conclusion
- Sample Problems on Fick’s Law of Diffusion
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