Environment

Properties of Gases Kinetic Theory of Gases Many independent particles Random motion at high speed Separated by great distances Kinetic Theory of Gases Interact only when they collide 5. Elastic collisions Physical Properties of Gases Diffusion Effusion Permeability Compressibility Expansibility Diffusion spontaneous mixing due to particle motion Effusion gas particles passing through a tiny opening into an evacuated area Both diffusion and effusion are directly related to the speed of the gas molecules. rate of effusion for gas 1 Graham?s Law of Effusion rate of effusion for gas 2 = molar mass2 molar mass1 molar massN = 28.02 g/mol Sample Problem 1 Calculate the ratio of effusion rates between nitrogen (N2) and Argon (Ar). molar massAr = 39.95 g/mol rate of effusion for gas 1

Energy and Matter Energy Energy the ability to do work Work Work a force moving matter through a distance Both energy and work are measured in joules (J). Forms of Energy Mechanical ? objects Kinetic ? moving Potential ? stored Thermal ? kinetic energy of atoms and molecules Forms of Energy Acoustic (sound) ? periodic, wave-like motion of atoms and molecules Electromagnetic ? moving electrons Chemical ? breaking and forming bonds Forms of Energy Nuclear ? from center of atom 6 Energy Conservation Despite Change ?the study of the flow of energy? Thermodynamics ?the law of conservation of mass-energy? (Conservation doesn?t refer to turning off the lights.) First Law of Thermodynamics ?the law of conservation of mass-energy?