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Unformatted text preview: System Boundary 3) T hermodynamic properties : For engineering purposes, we want "averaged" information, i.e., macroscopic not microscopic (molecular) description. (Knowing the position and velocity of each of 1020+ molecules that we meet in typical engineering applications is generally not useful.) 4) S t ate of a syste m : The thermodynamic state is defined by specifying values of a (small) set of measured properties which are sufficient to determine all the remaining properties. 0-3 5) E quilibrium : The state of a system in which properties have definite (unchanged) values as long as external conditions are unchanged is called an equilibrium state. Properties ( P , pressure, T , temperature, , density) describe states only when the system is in equilibrium. ? ? Mg + PoA = PA Gas at Pressure, P Mass Mechanical Equilibrium Po Insulation Copper Partition Thermal Equilibrium Gas T1 Over time, T1 T2 Gas T2...
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- Fall '10