Chemistry and Chemical Reactivity Essay
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The Kinetic Molecular Theory of Gases (KMT) is an explanation and description of the motion and behavior of molecules. It looks into the kinematics of molecules, wherein focus on the forces exists between molecules and the energy generated by the motion of these molecules (Poseidon Software and Invention, 1997). Etymologically, the KMT comes from “kinetic” which means moving, and “molecular” which comes from the root word molecule, classically the smallest unit of particle.
The KMT includes several postulates which describe how the molecules of gases behave.
The following are characteristics of how gas molecules behave: (1) Gases are composed of very small particles called molecules; (2) the molecules are very large in number; (3) they are perfectly spherical in shape and elastic in nature; (4) their volume is negligible which implies that they can move freely (Dogra, 1984); (4) the average distance between molecules is relatively large as compared to their size (Kotz, et al. , 2008); (5) they behave in a state of constant, random motion following Newton’s Laws (Selvaratnam, 1998); (6) they move in a straight line until they “collide with another [particle or with] the walls of the container” (Whitley, 2005, n.
(7) the collisions of the gas molecules with other particles or with the walls of the container are perfectly elastic such that the total kinetic energy after the collision is equal to the total kinetic energy before the collision; (8) there are no attractive or repulsive forces between the molecules, and only during collisions do the particles exert forces on each other (Wulfsberg, 2000); (9) there is no energy lost during the collisions; energy is conserved; and (10) the average kinetic energy of the particles depends on the temperature of the system.
These postulates can be further illustrated in terms of the interpretation of the temperature and pressure of a gas. Temperature, being a macroscopic characteristic of matter, is “interpreted in terms of the kinetic energy of the molecules” (Selvaratnam, 1998, p. 183). There is a directly proportional relationship between the temperature and the kinetic energy of the molecules of a gas. This means that an increase in temperature causes a similar increase in the kinetic energy or rapid movement of the molecules.
“The hotter the gas is, the faster its particles move” (Whitley, 2005, n. p. ). Pressure, on the other hand, is “due to the incessant bombardment of the walls of the container vessel by the billions and billions of molecules present” (Selvaratnam, 1998, p. 183). This only means that if more collisions occur, the pressure is higher. The individual gas laws could be put into perspective in relation to the KMT. According to Boyle’s Law, “at constant number of moles and temperature, pressure and volume are inversely proportional” (Whitley, 2005, n. p. ).
Charle’s Law, on the other hand, states that “at constant number of moles and pressure, the volume and the temperature are directly proportional” (Whitley, 2005, n. p. ). A third Gas Law consists of the theory that “at constant number of moles and pressure, the volume and the temperature are directly proportional” (Whitley, 2005, n. p. ). These individual gas laws, if combined, would produce an “ideal” gas. In relation to the motion of the molecules, the molecular activities in the three states of matter differ in several aspects.
In the solid state, the particles are packed in a more closely manner. They are held closely to one another by their attractive forces (Poseidon Software and Invention, 1997). These strong, attractive forces between the particles cause them not to move freely and instead, vibrate. This feature results in a definite shape and volume of solids. In the liquid state, the intermolecular forces only permit the particles to flow or glide over one another. As compared to solid, the motion of the molecules is more random.
The shape and volume of a liquid is dependent on its container. The intermolecular forces are also essential in understanding the dissolution of things. In the dissolving process, the molecules of the solute are surrounded by the molecules of the solvent. Here, “molecular bonds between molecules of solute have to be broken and molecular bonds of the solvent also have to be disrupted” (Educating Online, 2007, n. p. ).
Blauch, D. N. (2001). Kinetic Molecular Theory. Retrieved March 6, 2009 from http://www. chm. davidson. edu/chemistryapplets/kineticmoleculartheory/BasicConcepts. html. Dogra, S. (1984). Physical Chemistry through Problems. India: New Age International. Educating Online. (2007). Solubility of things. Retrieved March 6, 2009 fromhttp://www. solubilityofthings. com/basics/why_things_dissolve. php Kotz, J. C. , Treichel, P. & Weaver. (2008).
Chemistry and Chemical Reactivity. U. S. : Cengage Learning EMEA Poseidon Software and Invention. (1997, November 16). Kinetic Molecular Theory. Retrieved March 6, 2009 from http://www.psinvention. com/kinetic. htm. Selvaratnam, M. (1998). A Guided Approach to Learning Chemistry. South Africa: Juta and Company Limited. The Kinetic Molecular Theory. (2009). Bodner Research Web. Retrieved March 6, 2009 from http://chemed. chem. purdue. edu/genchem/topicreview/bp/ch4/kinetic4. html. Whitley, K. (2005, May 13). Kinetic Molecular Theory of Gases. Retrieved March 6, 2009 from http://www. chemprofessor. com/kmt. htm. Wulfsberg, G. (2000). Inorganic Chemistry. U. S. :University Science Books.