Unformatted text preview: TC (September 16, 2008) *Lecture 5 Notes* * Ideal Gas Behavior deviation characteristics: ‐ A temperature decrease results in more deviation from Ideal Gas Behavior. ‐ A higher amount of pressure results in more deviation from Ideal Gas Behavior. *IDEAL GAS BEHAVIOR characteristics: ‐ At higher temperatures, there are decreases in the deviation from Ideal Gas Behavior. In other words, gases behave more ideally at higher temperatures. ‐ At lower pressures, the more “Ideal” the gas behavior is. *Three Phases of Matter: >> Gases: ‐ Gas particles are in complete chaos as they all have the freedom of motion. In between the particles is empty space. >> Liquids: ‐ Liquid particles are close to each other and are in clusters/groups. Like gases, they are also in some disorder but, not like gas particles. If one liquid particle were to move, another one can move in relation to it. >> Solids: ‐ Solid particles are neatly combined together to form a pattern that all of the particles abide by. The particles are close‐knit and in fixed positions. Motion occurs as vibrations both as the whole solid vibrating together, or as individual particles vibrating in place. * Phase changes: ~ Kinetic Energy: It is the energy of Motion. ~Potential Energy: It is the energy of Separation. ‐ Melting = Solid to Liquid (energy must be added) ‐ Fusion/Freezing = Liquid to Solid (when energy is taken away). ‐ Vaporization/Boiling = Liquid to Gas (energy added, vaporization occurs at the surface of the liquid). ‐ Condensation = Gas to Liquid (when energy is taken away). ‐ Sublimation = Solid to Gas (energy added). ‐ Deposition = Gas to Solid (energy taken away) *Heating Curve: ‐ The relationship between the Temperature and the Heat Added. ‐ Rising, diagonal lines are the increase in Kinetic Energy. ‐ Horizontal, straight lines are the Potential Energy Increase. ‐ The opposite, Cooling Curve, is when the temperature changes when energy is removed. *Phase Diagram: ‐ Shows the relationship between Pressure and Temperature. ‐ Critical Point: > It is the exact pressure and temperature beyond which you can no longer tell the difference between the liquid and gas. ‐ Liquid, Solid, and Gas are represented with boundaries around them. The boundary lines are the equilibrium lines where both phases are present. * Vapor Pressure: ‐ It is the pressure exerted by the gas particles that boil/evaporate or sublime between the phase changes of a liquid and/or solid. ‐ When this reaches the pressure of whatever gas is around the substance, the substance is either “boiling” (Liquid to Gas) or “subliming” (Solid to Gas). ‐ If the pressure around the substance is equal to 760 mmHg = 1 atm, then the temperature where the vapor pressure equals that is called the normal boiling point. ‐ All liquid and most solids have vapor pressure. > At standard pressure, solids will go through a phase change to liquid when the temperature is raised. > At standard pressure, some solids will “sublime”. ‐ In a Liquid to Gas phase change, the temperature changes as you add heat to a liquid below its boiling point. > When the temperature increases, vapor pressure increases. > When the temperature decreases, vapor pressure decreases. ...
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This note was uploaded on 12/02/2011 for the course PHYSICS 235 taught by Professor Staff during the Fall '08 term at Rutgers.
- Fall '08