Diffusion

Matter flow velocity

(I) is number of particles that pass within a given time.

Diffusion

is faster in low viscosity media than in high viscosity media.

Matter flow velocity

(I) is number of particles that pass within a given time.

Diffusion

is faster in low viscosity media than in high viscosity media.

Average distance

(R) is proportional to the square root of Diffusion coefficient (D) × time.

Matter flow density

(J) is amount of particles with time divided by area (A)

gas exchange

In between lungs and bloodstream, oxygen and nutrient transport to tissues and cells from bloodstream, waste products of metabolism is transported to the blood.

Particle properties

determining diffusion coefficient.

constant motion

A container split into two parts, the molecules in both sides are in and collide with themselves and the wall of the container.

Ficks 1st law matter flow density

is linearly proportional to concentration and diffusion gradient.

spherical particles

In , environmental factors relate with the diffusion coefficient.

higher concentration

The particles move from a solution of to lower concentration till we achieve a homogeneous distribution.

Diffusion

is the movement of particles from an area of higher concentration to an area of lower concentration over time by random thermal motion.

diffusion

It indicates that is faster for smaller particles.

Example

gaseous exchange between the blood and the lungs; for CO2 R is 1micrometer, D is 1.2 × 10^-8 time is about 0.5s

Stokes

D = 𝑘/6𝜋 × 𝑇/𝜂𝑟

Relationship between diffusion time and mean displacement

R~√2𝐷𝑡 ×𝑡

Diffusion for particle size

diffusion is faster for smaller particles.

Diffusion coefficient

particle properties determining diffusion coefficient.

Effect of concentration on diffusion

Increase in concentration leads to increased diffusion rate

Cause of diffusion

Due to the uneven(inhomogeneous) distribution of particles

Difference between diffusion and osmosis

Diffusion needs no permeable material