The Kinetic Molecular Theory of Matter

The Kinetic Molecular Theory of matter attempts to describe all the states of matter and the conversion between the states by considering the structures of molecules comprising matter and how those molecules interact. There are three commonly encountered states of matter solids, liquids, and gases. There are a few other states of matter, such as plasmas, but these are encountered only under extremely high energy conditions. Therefore, we will restrict our conversation to the more mundane states. 

Rationalize the defining characteristics of the states of matter in terms of intermolecular forces and the kinetic molecular theory of matter. 

Demonstrate an understanding of the kinetic molecular theory of matter. 

SECTION 1 The Kinetic-Molecular Theory of Matter KEY TERMS ... 

There are general relationships of transport phenomena based on phenomenological theory, i.e., on the correlations between macroscopically measurable quantities. The molecular theories explain the mechanism of transport processes taking into account the molecular structure of the given medium, applying the kinetic-statistical theory of matter. The hydrodynamic theories are also applied especially to describe - convection. 

LIQUIDS OR SOLIDS IN MANY WAYS. MOLECULAR MOTION IN GASES IS TOTALLY RANDOM, AND THE FORCES OF ATTRACTION BETWEEN GAS MOLECULES ARE SO SMALL THAT EACH MOLECULE MOVES EREELY AND ESSENTIALLY INDEPENDENTLY OF OTHER MOLECULES. SUBJECTED TO CHANGES IN TEMPERATURE AND PRESSURE, GASES BEHAVE MUCH MORE PREDICTABLY THAN DO SOLIDS AND LIQUIDS. ThE LAWS THAT GOVERN THIS BEHAVIOR HAVE PLAYED AN IMPORTANT ROLE IN THE DEVELOPMENT OF THE ATOMIC THEORY OF MATTER AND THE KINETIC MOLECULAR THEORY OF GASES. 

The answer is yes and we will digress a bit at this point to introduce these concepts as we did earlier in the chapter. The temperature and pressure conditions that govern physico-chemical behavior of liquids are defined in terms of thermodynamics. The Gibbs Phase Rule is a direct outcome of the physical chemistry of changes in the state of matter. The phase rule helps to interpret the physico-chemical behavior of solids, liquids, and gases within the framework of the kinetic-molecular theory of phase equilibria. 

Gases, the subject of this chapter, are simpler than liquids and solids in many ways. Molecular motion in gases is totally random, and the forces of attraction between gas molecules are so small that each molecule moves freely and essentially independently of other molecules. Subjected to changes in temperature and pressure, it is easier to predict the behavior of gases. The laws that govern this behavior have played an important role in the development of the atomic theory of matter and the kinetic molecular theory of gases. 

In the chapter States of Matter, you read about the kinetic-molecular theory, which is based on the idea that particles of matter are always in motion. In this section, you will study the implications of the kinetic-molecular theory of gases. 

For a quantitative description of the behavior of gases, we will employ some simple gas laws and a more general expression called the ideal gas equation. These laws will be explained by the kinetic-molecular theory of gases. The topics covered in this chapter extend the discussion of reaction stoichiometry from the previous two chapters and lay some groundwork for use in the following chapter on thermochemistry. The relationships between gases and the other states of matter— liquids and solids—are discussed in Chapter 12. 

Although the kinetic-molecular theory was developed to explain the behavior of gases, the model can be applied to liquids and solids. When applying the kinetic-molecular theory to these states of matter, you must consider the forces of attraction between particles as well as their energy of motion. 

I See the Saunders Interactive General Chemistry CD-ROM, Screen 1 3.2, Phases of Matter the Kinetic-Molecular Theory. This screen contains an animated version of Figure 13-1. 

COMPETENCY 15.0 APPLY KNOWLEDGE OF THE KINETIC MOLECULAR THEORY TO THE STATES OF MATTER, PHASE CHANGES, AND THE GAS LAWS. 

The Kinetic Molecular Theory provides a simple model of the nature of matter. It has the following components ... 

We can apply the kinetic-molecular theory quantitatively to phase changes by means of a heating-cooling curve, which shows the changes that occur when heat is added to or removed from a particular sample of matter at a constant rate. As an example, the cooling process is depicted in Figure 12.3 for a 2.50-mol sample of gaseous water in a closed container, with the pressure kept at 1 atm and... 

The ideas presented above are expressed in a general theory of the physical properties of matter called the kinetic-molecular theory. The theory is based on the following propositions ... 

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