chem 211 6 notes

chem 211 6 notes - Systems states and energy Systems Energy...

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Systems states and energy Systems Energy my be transformed from one form into another, transformed from one place to another Region we are interested is the system, what it is immersed in is the surroundings Open system can exchange mater and energy w/ surroundings Closed system has fixed amount of matter, but can exchange energy Isolated system has no contact w/ surroundings Work and energy Work is motion against an opposing force Capacity of a system to do work in thermodynamics is its internal energy , U U=w expansion work work of expansion against an external force ex. Gas in a cylinder expanding against atmosphere (change in volume) nonexpantsion work does not involve a change in volume if external pressure is zero w= 0 a system does no work when it expands into a vacuum— free expansion reversible process one that can be reversed by infinitesimal change in a variable ex. If external pressure exactly matches internal pressure, a small change will change the volume irreversible process is one where an infinitesimal change will not change the volume reversible processes most important ln( ) final initial V w nRT V = - heat heat is energy transferred as a result of a temperature difference U=q sign of q indicates whether heat has left or entered the system exothermic when heat is released into surroundings endothermic when heat is absorbed by process measurement of heat heat capacity is ratio of heat supplied to rise in temperature q C T = heat capacity related to size of sample
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This note was uploaded on 08/17/2009 for the course CHEM 211 taught by Professor Crane, b during the Fall '06 term at Cornell.

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chem 211 6 notes - Systems states and energy Systems Energy...

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