Thermodynamics Paper - Essay Example

of Learning: Thermodynamics Paper In general a phase diagram demonstrates the variations between different states of element matter in regards to their response to pressure and temperature. This paper is aimed at closely analyzing the pressure- temperature phase (P-T) diagrams of both water (H2O) and carbon dioxide (CO2). In addition to this paper illustrating the phase diagrams, it will go deeper into evaluating all the possible phase changes that this pure substance can make at atmospheric pressure.

Lastly, the paper will discuss the Common applications of these phase changes.Phase diagrams plots pressure (normally in the atmospheres) against temperature (classically in degrees Celsius). With most substances, the temperature and pressure related to the triple point lie below standard temperature and pressure and the pressure for the critical point lies above standard pressure.  Generally, at normal pressure, as temperature rises, most substances convert from their solid state, to liquid and lastly to a gaseous state.

In the same reverse sequence, at standard temperature as pressure decreases, most substances change from the gaseous state to liquid and eventually to the solid state.The phase diagram of H2O and CO2 Phase diagrams for CO2 Phase diagrams for H2O (diagrams n.p)Possible phase changes that pure water can make at atmospheric pressureAs noted earlier there are three states of matter, these state are commonly referred to as the phases and they are gas, liquid, and water.

In addition to this it is well evidenced that most substances can exist in different states under different conditions, mainly the surrounding temperature and pressure. In the case of water it exists as a solid i.e. ice at temperatures below 0o C, and as a gas at temperatures above 100o C.It is important to understand that in most cases the evaluation of these different states is commonly carried out in the near earth environment. This is important to be noted because any given environment is mainly characterized by the temperature and pressure (Gupta 180).

Hence under these two parameters, water is in its liquid state at normal atmospheric pressure and at a temperature of 99o C, however, when the pressure is at 71 cm and the temperature remain constant at 99o C the phase is changed to a gas. In most substances their boiling points are lowered as the pressure decreases, moreover, their melting point reduces as the pressure decreases. However, the melting point of water is an exception to this rule; ‘It gets lower as the pressure gets higher’ (Gupta 79)Possible phase changes that pure Carbon dioxide can make at atmospheric pressureReal gases react in the same way just like ideal gases at high temperatures.

However, under low temperatures the connections between the molecules and their volume is very important. For example the molecules are very close therefore causing condensation in addition, to the volume reducing. As such the phase changes from a gas to a liquid. Consequently if the liquid phase is subjected to extremely low temperatures the phase is change to solid. Conversely, the volume is reduced but can never reach zero due to the finite volume of its molecules.Moreover, pressure also causes a phase change in carbon dioxide.

At room temperature and atmospheric pressure carbon dioxide is a gas, however if the pressure is considerably increased, it changes its state from a gas to a liquid. Contrarily, when the pressure is reduced, it causes the temperature to decrease resulting to a further change in phase of the liquid to solidify (Gupta 182). Common applications of these phase changes.1. Telecom Shelters where phase change materials (PCMs) are use so that they can absorb heat in the absence of power. They store energy and release it in the absence of power thus saving diesel costs.2. Transportation perishable goods like foods, pharmaceuticals sundry electronics and explosives.3. House heating, warm water; in the case where there are power failures the PMCs will release their stored power thus keeping the temperatures in check.4. Construction materials: Construction materials; they are used to release the same properties that thick walls have in controlling the room’s temperature.5. Automobiles; where they are used to store power that is used during a cold start event in addition to regulation the interior driving comfort.6. Green Houses; where they are used to regulate and maintain a stable temperature inside the greenhouse.7. Temperature Peak Stabilization; mainly required in the chemical industry because refrigeration and heating are necessary in a single batch. 8. Catering; to keep the food in the right temperature without being overcooked.9. Electronics: They are used to regulate the internal temperature of the machine so that it can work efficiently.

Works CitedDiagrams, Phase. Phase Diagrams. n.d. 15 Feb 2013 .Gupta, S. C. . Thermodynamics. Indianapolis: Pearson Education India, 2005.