what is diffusion?

Question

s.b.a

Answer 1

invest in a dictionary

Answer 2

If you're talking about diffusion of a cell, then diffusion is molecules moving through the membranes of a cell. Like exchanging gases, taking in water, food, and eliminating wastes. There are two different ways these things can move through a membrane: active and passive transport. Active transport requires the cell to use energy. While Passive transport does not. Usually it occurs spontaneously.

Answer 3

Diffusion is the net action of matter (particles or molecules), heat, momentum, or light whose end is to minimize a concentration gradient. The process of diffusion, therefore, minimizes thermodynamic Gibbs free energy (though, it is not a chemical reaction), and is thus a spontaneous process (more familiarly known as a "passive" form of transport, rather than "active"). An example of diffusion is seen when one cooks spaghetti, where water diffuses into the sponge-like structure of the dry and stiff pasta. (Note that the heat provided by cooking does not cause but expedites this process).

The different forms of diffusion can be modeled quantitatively using the diffusion equation, which goes by different names depending on the physical situation. For instance - steady-state bi-molecular diffusion is governed by Fick's law, steady-state thermal diffusion is governed by Fourier's law. The diffusion of electrons in an electrical field leads essentially to Ohm's law that is further explained by Einstein relation. The generic diffusion equation is time dependent, and as such applies to non-steady-state situations as well.

In all cases of diffusion, the net flux of the transported quantity (atoms, energy, or electrons) is equal to a physical property (diffusivity, thermal conductivity, electrical conductivity) multiplied by a gradient (a concentration, thermal, electric field gradient). Noticeable transport occurs only if there is a gradient - for example in thermal diffusion, if the temperature is constant, heat will move as quickly in one direction as in the other, producing no net heat transport or change in temperature.

The second law of thermodynamics states that in a spontaneous process, the entropy of the universe increases. Change in entropy of the universe is equal to the sum of the change in entropy of a system and the change in entropy of the surroundings. A system refers to the part of the universe being studied; the surroundings is everything else in the universe. Spontaneous change results in dispersal of energy. Spontaneous processes are not reversible and only occur in one direction. No work is required for diffusion in a closed system. Reversibility is associated with equilibrium. Work can be done on the system to change equilibrium. Energy from the surroundings decrease by the amount of work expended from surroundings. Ultimately, there will be a greater increase in entropy in the surroundings than the decrease of entropy in the system working accordingly with the second law of thermodynamics.[1]

Diffusion can be measured, by the means of concentration gradient. A concentration gradient is the difference between the high concentration and the low concentration. It also determines how fast diffusion occurs.

Answer 4

Diffusion is the movement of materials from a high concentration to a lower.

Answer 5

dif·fu·sion
Pronunciation: \di-ˈfyü-zhən\
Function: noun
Date: 14th century
1: the action of diffusing : the state of being diffused
2: prolixity, diffuseness
3 a: the process whereby particles of liquids, gases, or solids intermingle as the result of their spontaneous movement caused by thermal agitation and in dissolved substances move from a region of higher to one of lower concentration b (1): reflection of light by a rough reflecting surface (2): transmission of light through a translucent material : scattering
4: the spread of cultural elements from one area or group of people to others by contact
5: the softening of sharp outlines in a photographic image
— dif·fu·sion·al \-ˈfyü-zhə-nəl\ adjective

Answer 6

a process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated

basically it means that the molecules in lsay a glass of water move around to maintain equilibrium

Answer 7

when molecules move from a higher and a lower concentration until equilibruim occrs(when the same amount of molecules are on both sides) they still continue to move afterwards, but not as rapidly =)

Answer 8

moving from a high concentration to a lower concentration in order to balance