Diffusion is the movement of particles from regions of high
concentration towards regions of lower concentration.
LEARNING OBJECTIVES [ edit ]
Discuss results of diffusion
Describe process of diffusion
Identify factors that affect rate of molecular diffusion
KEY POINTS [ edit ]
Molecular diffusion, often called simply diffusion, is the thermalmotion of all (liquid or gas)
particles at temperatures aboveabsolute zero.
The result of diffusion is a gradual mixing of material. In aphase with uniform temperature,
absent external net forcesacting on the particles, the diffusion process will eventually result in
complete mixing.
It is important to note that diffusion also occurs when there is no concentration gradient.
At equilibrium particles are still moving around their container.
TERMS [ edit ]
equilibrium
The state of a body at rest or in uniform motion, the resultant of all forces on which is zero.
diffusion
Diffusion is the movement of particles from regions of high concentration toward regions of lower
concentration.
concentration
The proportion of a substance in a mixture.
Give us feedback on this content: FULL TEXT [edit ]
Diffusion is the movement of particles
move from an area of high concentration
to an area of low concentration until
equilibrium is reached . A distinguishing
feature of diffusion is that it results in
mixing or mass transport without
requiring bulk motion. Thus, diffusion
should not be confused with convection or
advection, which are other transport
mechanisms that use bulk motion to move
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particles from one place to another.
Diffusion
Particles moving from areas of high concentration to areas of low concentration.
From the atomistic point of view, diffusion is considered a result of the random walk of the
diffusing particles. In molecular diffusion, the moving molecules are self-propelled
by thermalenergy. Random walk of small particles in suspension in a fluidwas discovered in
1827 by Robert Brown and the aptly namedtheory of Brownian motion and the atomistic
backgrounds of diffusion were further developed by Albert Einstein. At present, the concept
of diffusion is widely used in science: from physics (particle diffusion) to economics and
finance (diffusion of people, ideas and of price values). It appears every time the concept of
random walk in ensembles of individuals is applicable.
Molecular diffusion, often called simply diffusion, is the thermal motion of all (liquid or gas)
particles at temperatures above absolute zero. The rate of this movement is a function of
temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the
net flux of molecules from a region of higher concentration to one of lower concentration, but
it is important to note that diffusion also occurs when there is no concentration gradient. The
result of diffusion is a gradual mixing of material. In a phase with uniform temperature,
absent external net forces acting on the particles, the diffusion process will eventually result
in complete mixing.