01 Notes - Phase Changes

01 Notes - Phase Changes - Endothermic Process that...

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Pluchino – Regents Chemistry Phases of Matter – 01 Phase Changes Aim: What is occurring during phase changes? Do Now: How can you change the phase of matter? Temperature: the average kinetic energy of the molecules of a substance T K = T C + 273 As temperature increases the molecules of a substance have more freedom to move around. Pressure: the force area applied on a surface in a direction perpendicular to that surface 1 atm = 760 torr = 760 mm of Hg = 101.3 kPa As pressure increases, molecules are forced closer together and their movement is restricted. Practice: Convert. 1. If oxygen exists as a liquid at -223 o C, what is that temperature in Kelvin? 2. Thermite burns at 2500 o C, what is that in K? 3. The pressure in an oxygen tank is roughly 1.55 x 10 5 torr. How many atmospheres is that? Critical Point: Gas and liquid are indistinguishable Triple Point: All phases of matter exists simultaneously Exothermic: Process that releases heat/energy into the environment, thus increasing the temp of the surroundings
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Unformatted text preview: Endothermic: Process that requires heat/energy from the environment, thus decreasing the temp of the surroundings Change Name Exo or Endo? Solid to liquid Melting Endo Liquid to gas Vaporization Endo Solid to gas Sublimation Endo Liquid to solid Freezing Exo Gas to liquid Condensation Exo Gas to solid Deposition Exo What is happening to all that energy if the temperature is not increasing? Energy is used to break intermolecular attractions between molecules Conclusions: Know how to convert between units when dealing with temperature and pressure The triple point on a phase diagram shows the conditions when a solid, a liquid and a gas all exist simultaneously Know the phase changes and whether they are exothermic or endothermic Temperature remains constant during a phase change...
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This note was uploaded on 01/01/2012 for the course CHEM 101 taught by Professor Donahue during the Spring '11 term at Long Island U..

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01 Notes - Phase Changes - Endothermic Process that...

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