States of Matter and Phase Change - Assignment Example

Submitted by: XXXXXXXX Number: XXXXXXXX XXXXXXXX XX – XX – 2009 Matter Matter, in simple words, is everything that has a mass and can occupy a volume. The basic components of matter include atoms and molecules. Atoms and molecules are the building blocks of matter in this universe. Matter exists in different states and can also change from one state to another. This is known as the phase change (Templer, 2009). 1. States of Matter: State of matter can be best described as the amount of heat contained within the molecules. When more heat is added, the molecules move far from one another. The state of matter can thus be linked closely to the temperature and the pressure of the substance under consideration (Bayrock & Fiona, 2007). Traditionally, states of matter were classified based upon the density and the space between the molecules. However, with recent advancements, the classifications are mainly based on the molecular interrelationships. There are totally five states of matter, namely, Solid, Liquid, Gas, Plasma and Bose- Einstein condensate. The first four have been identified a long time ago, whereas the Bose-Einstein condensate was recently identified in 1995 (Giancoli, 2004). 2. Phase Change: It is a known fact that ‘Matter can neither be created nor be destroyed. It can only transform from one state to another’ (Giancoli, 2004). There are a total of six phase change processes, namely, melting, vaporization, freezing, sublimation, condensation and deposition. It is imperative to note that the phase change does not affect the chemical composition and the chemical properties of matter. Only the arrangement of particles (atoms, ions or molecules) and their interrelationships change. For instance, each molecule of liquid oxygen has two atoms of oxygen as that of oxygen gas, and both these states have the same chemical properties. In liquid oxygen, the molecules however exist in a cooler state and are closely arranged, when compared to that of the gaseous state (Bayrock & Fiona, 2007). 3. Solids: In solid matter, the space or the void between the atoms and molecules are minimal. The average distance between two molecules in solids is of the order of 10-8 cm. Hence they exist in incompressible state and their movements are completely restricted. Solids also have a definite shape and size. Kinetic energy refers to the energy of a particle attained due to its state of motion. In the case of solids, the kinetic energy of the particles is at a minimum level as the motion is restricted. It is also difficult to compress the solid, as the molecules are already very closely packed (Bodach, 2005). 4. Liquids: When solids are heated and melted, the void between the particles increases and they become unstable. Evidently the solid loses its shape, whereas the volume remains definite. This state of matter is known as Liquid State. Liquids tend to fill up the shape of the container and their flow is mainly controlled by gravity. It is also difficult to compress the liquids, as liquids have moderate cohesive forces that keep the molecules close to one another (Giancoli, 2004). The process of heating the solid above its melting point to transform into a liquid is referred to as the melting process. Above this melting point, the binding or the cohesive force between the molecules are broken by transferring energy into the particles in the form of heat. In other words, more energy is transformed into the particles by heating and the kinetic energy of the particles increase. This results in the solid being transformed into a liquid. Similarly, a liquid can also be cooled down below its freezing temperatures and the molecular distances will reduce, making it a solid. This process of transforming liquid into a solid is known as the freezing or the fusion process. In this case, energy is released to the universe, i.e., kinetic energy is released in the form of heat (Tillery, 2004). 5. Gases: The third state of matter is the gas state, in which the particles are freely arranged. The gas molecules possess energy due to their motion. This kinetic energy of the gas molecules makes the intermolecular forces to be negligible. In an ideal case, the intermolecular forces are equal to zero (Gaincoli, 2004). The liquids can be transformed into gases by heating them above their boiling points. The molecular forces will decrease forcing them to detach and undergo a phase change to form a vapor. This process is known as vaporization. In this case also, the heat energy is transformed into kinetic energy and the intermolecular forces are reduced. Heat is transferred from the surrounding universe into the particles and hence this phenomenon is mainly applied in air conditioning systems. Similarly, the gas molecules can be cooled below their boiling points and pressurized to suppress the kinetic energy and transform them to liquids. This process is known as condensation. As heat is being transferred into the universe in this process, it is mainly applied in heaters (Tillery, 2007). The gases can be converted to solids directly. For instance, at sub- freezing air temperatures, water vapor transforms directly into ice without first becoming water. This process is known as deposition. The reverse of this process, in which, solids are directly converted to gases, is termed as sublimation. A classic example will be that of dry ice transforming to vapor CO2 (Carbon di- oxide) at room temperature (Oxtoby & Nachtrieb, 1996). 6. Governing Laws: In 1802, Gay – Lussac proposed that gases tend to expand when heated. This was initially proposed by Jacques Charles in 1780s, but first published by Gay – Lussac. Hence this law was named as the Charles Law. This law was more perfected and the modern Charles Law states that ‘At constant pressure, the volume (V) of a given mass of an ideal gas increases or decreases by the same factor as its temperature (T) on the absolute temperature scale (i.e. the gas expands as the temperature increases)’ (Tillery, 2007). V α T This law is based on an ideal gas assumption, which indicates that pressure and number of molecules are kept constant, and that the intermolecular forces are equal to zero. Another important law to be considered is the Boyle Law, proposed by Robert Boyle in 1662. The law states that for a fixed amount of gas kept at a constant temperature, pressure (p) and volume (V) are inversely proportional (Gaincoli, 2004). p α 1 / V pV = Constant Both the Charles Law and Boyles Law were combined by Emile Clapeyron in 1834 to form the ideal gas equation, which states that pV = nRT where n is the constant (amount of gas substance at the given pressure p) (Tillery, 2007). 7. Plasma: Plasma is considered to be a distinct state of matter, as it is a partially ionized gas. Part of the electrons of the atoms, are free to move independently and hence they are electrically conductive and respond to strong electromagnetic fields. Plasmas do not have a definite shape and volume and take up the shape of the container, similar to a gas. Ionization or the formation of free ions (charged particles) is necessary for plasma to exist. The degree of ionization of plasma is the ratio of number of charged ions to the sum of neutral and charged ions present. This measure indicates the plasma density, that is, the number of free electrons per unit volume. Matter made of plasma can be controlled using magnetic fields, to form filaments and other structures (Goldston & Lutherford, 1995). The most commonly used plasmas are the fluorescent and neon lights. When electricity is passed through the tube, the electrons and ions in the gas are excited and they form plasma with free electrons and ions. Plasma glows in a particular color depending on the type of gas filled in the tube (Giancoli, 2004). 8. Bose- Einstein Condensate: The Bose- Einstein condensate which was recently added to the list of states of matter was first proposed by Albert Einstein and Satyendranath Bose. According to them, the matter that exists at a colder temperature than the solid is the Bose- Einstein condensate. This state of matter was finally produced experimentally in 1995 by Wolfgang Ketterle. The Bose- Einstein condensate is produced when the building atoms of the matter exist at equivalent quantum levels and at a temperature very close to -273 oC (Griffin & Stringari, 1995). This temperature of -273 oC is referred to as the absolute zero temperature or 0 Kelvin. This temperature is impossible to attain by a matter, as there will be energy transformations at all times with the universe. In other words, there should not be any movement of molecules and hence no kinetic energy should exist. It is theoretically impossible to separate matter from universe and hence absolute zero is impossible to attain (Helmenstine, 2009). Works Cited Bayrock, and Fiona States of Matter: A Question and Answer Book. USA: Capstone Press, 2007. Bodach, Vijaya .K.. States of Matter (Reading Essentials in Science - Physical Science). USA: Perfection Learning, 2005. Giancoli, D. C. . Physics: Principles with Applications. New York: Prentice Hall Publishers, 2004. Goldston, R. J., and Rutherford, P. H. . Introduction to Plasma Physics. London: Taylor and Francis, 1995. Griffin , Allan D. W., and Stringari Snoke, S. . Bose-Einstein condensation. Melbourne: Press Syndicate of the University of Cambridge, 1995. Helmenstine, Ph.D., Anne Marie . "What Is Absolute Zero?". About.com. 30th September 2009 . Oxtoby, and Nachtrieb Principles of Modern Chemistry, 3rd ed... Saunders College Publishing: 1996. Templer, Inner. What is Matter?. LLC: Bibliolife, 2009. Tillery, B. . Physical Science. London: Mc – Graw Hill – Science, 2007. Read More