Chapter 11 - dont remember prof PDF

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Chapter 11 Gases 

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Kinetic Molecular Theory o Gases are the least dense phase of matter o Consist of free gaseous atoms/molecules in constant random motion, colliding with other molecules and their container Gas Behavior o Expand to fill container o Compressible o Pressure is the result of gas molecules colliding with their container o Earth’s atmosphere exerts pressure at its surface due to its mass o This pressure is assigned a value of 1 atmosphere (atm) at sea level o Common units of pressure  1 atm = 14.7 lb/in2(psi) = 101,325 Pa =101.325 kPa  Perfect vacuum is 0 atm  Pressure of outer space is 10-13 torr Atmospheric Pressure o Supports the column to a height of 760 mmHg o Units of pressure  1 atm = 760 mm Hg  1 atm = 29.92 in Hg  1 atm = 760 torr  1 atm = 14.7 psi Kinetic Molecular Theory o Four key description of an ideal gas  Collection of particles in constant motion  No attractions or repulsions between molecules; collisions are inelastic  Space between molecules are much, much larger than molecules themselves  Average kinetic energy (KE = ½ mv2) proportional to temperature; increasing velocity of molecules increases temperature o This theory is sufficient for describing gas behavior in many cases o It is not appropriate in all circumstances. When would it fall?  If the gas molecules become too close together (high pressure)  If the assumption that there are no forces between gas molecules is incorrect (as it is in some cases) o Gases are compressible because of the large average distance (empty space) between molecules o Random motion will cause a gas introduced to a container to fill it o Gases less dense than solids and liquids because of the space between molecules o If 12 oz of water is boiled, the steam would fill 595 L (158 gal). Most of this is empty space...