Kinetic-molecular theory diffusion

Transport of the gas to the surface and the initial interaction. The first step in heterogeneous reactions involving the uptake and reaction of gases into the liquid phase is diffusion of the gas to the interface. At the interface, the gas molecule either bounces off or is taken up at the surface. These steps involve, then, gaseous diffusion, which is determined by the gas-phase diffusion coefficient (Dg) and the gas-surface collision frequency given by kinetic molecular theory. 

The statistical basis of diffusion requires arguments that may be familiar from kinetic molecular theory. Elementary concepts from the theory of random walks and its relation to diffusion form the third topic, which is covered in Section 2.6. As is well known, the random walk statistics can also be used for describing configurational statistics of macromolecules under some simplifying assumptions this is outlined in Section 2.7. 

Diffusion and effusion According to the kinetic-molecular theory, there are no significant forces of attraction between gas particles. Thus, gas particles can flow easily past each other. Often, the space into which a gas flows is already occupied by another gas. The random motion of the gas particles causes the gases to mix until they are evenly distributed. Diffusion is the term used to describe the movement of one material through another. The term may be new, but you are probably familiar with the process. If you are in the den, can you tell when someone sprays perfume in the bedroom Perfume particles released in the bedroom diffuse through the air until they reach the den. Particles diffuse from an area of high concentration (the bedroom) to one of low concentration (the den). 

Understand the kinetic-molecular theory and how it explains the gas laws, average molecular speed and kinetic energy, and the processes of effusion and diffusion ( 5.6) (SP 5.13) (EPs 5.53-5.65)... 

We observe that the kinetic-molecular theory helps us account for such gas properties as effusion, movement through tiny openings, and diffusion, movement through another substance. 

Describe the kinetic-molecular theory of gases and how it explains the pressure and temperature of a gas, the gas laws, and the rates of effrision and diffusion. (Sections 10.7 and 10.8)... 

KINETIC-MOLECULAR THEORY OF GASES EFFUSION AND DIFFUSION (sections 10.7 and 10.8)... 

MOLECULAR EFFUSION AND DIFFUSION (SECTION 10.8) It Mows from kinetic-molecular theory that the rate at which a gas undergoes effusion (escapes through a tiny hole) is inversely proportional to the square root of its molar mass (Graham s law). The diffusion of one gas through the space occupied by a second gas is another phenomenon related to the speeds at which molecules move. Because moving molecules undergo frequent collisions with one another, the mean free path—the mean distance traveled between collisions—is short. Collisions between molecules limit the rate at which a gas molecule can diffuse. 

Key Terms Kinetic-molecular theory (KMT) Ideal gas Diffusion Effusion Graham s law of effusion... 

Kinetic Molecular Theory of Gases Macroscopic properties like pressure and temperature of a gas can be related to the kinetic motion of molecules. The kinetic molecular theory of gases assumes that the molecules are ideal, the number of molecules is very large, and that their motions are totally random. Both gas diffusion and gas effusion demonstrate random molecular motion and are governed by the same mathematical laws. 

How the Kinetic-Molecular Theory Explains the Gas Laws 170 Effusion and Diffusion 175... 

Collapsing Can Liquid Nitrogen and Balloons Charles s Law A Graphical View Charles s Law A Molecular-Level View The Ideal Gas Law PV - nRT Visualizing Molecular Motion Single Molecule Visualizing Molecular Motion Many Molecules Kinetic-Molecular Theory/Heat Transfer Diffusion of Gases... 

Use the kinetic-molecular theory to explain the following properties of gases expansion, fluidity, low density, compressibility, and diffusion. 

How does the kinetic-molecular theory explain the foUowing properties of Uquids (a) relatively high density, (b) abiUty to diffuse, and (c) abiUty to evaporate ... 

The random motion of gas molecules gives rise to two readily observable phenomena diffusion and effusion. Diffusion is the mixing of gases as the result of random motion and frequent collisions (Figure 11.20), while effusion is the escape of gas molecules from a container to a region of vacuum (Figure 11.21). One of the earliest successes of the kinetic molecular theory was its ability... 

In all the previous gas law discussions in this chapter, no particular gas has been specified. We have always made reference to a gas or an ideal gas without saying if the gas is air, oxygen, carbon dioxide, ammonia, helium, or what. One of the tenants of the kinetic-molecular theory of gases is that all gases behave the same way in terms of compressibility, expansion, diffusion, pressure, and so on, and this ideal behavior extends to the gas laws. Thus, as long as a gas exhibits this ideal behavior, the gas laws hold for that gas. 

The kinetic molecular theory also allows us to predict the mean free path of a gas particle (the distance it travels between collisions) and relative rates of diffusion or effusion. 

Gas Properties Relating to the Kinetic-Molecular Theory— The diffusion and effusion of... 

It follows from this discussion that all of the transport properties can be derived in principle from the simple kinetic dreoty of gases, and their interrelationship tlu ough k and c leads one to expect that they are all characterized by a relatively small temperature coefficient. The simple theory suggests tlrat this should be a dependence on 7 /, but because of intermolecular forces, the experimental results usually indicate a larger temperature dependence even up to for the case of molecular inter-diffusion. The Anhenius equation which would involve an enthalpy of activation does not apply because no activated state is involved in the transport processes. If, however, the temperature dependence of these processes is fitted to such an expression as an algebraic approximation, tlren an activation enthalpy of a few kilojoules is observed. It will thus be found that when tire kinetics of a gas-solid or liquid reaction depends upon the transport properties of the gas phase, the apparent activation entlralpy will be a few kilojoules only (less than 50 kJ). 

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