Thermo, set 1

 system a quantity of matter or a region in space chosen for study surroundings physical space outside the system boundary boundary real or imaginary surface that separates the system from its surroundings. It may be fixed or movable. closed system exchange of energy but NOT matter open system (control volume), exchange of energy and matter control surface boundary of an open system isolated system can exchange NEITHER energy nor matter property a characteristic of a system in equilibrium. It is independent of the path used to arrive at the system condition. Intensive property independent of amount of material (i.e.temperature, pressure, age, color, etc.) Ratio of two extensive = intensive extensive property Dependent of amount of material (mass, volume, total energy, etc.) weight a force. W = mg equilibrium a system that maintains thermal (uniform temperature), mechanical (uniform pressure), phase (mass of two phases), and chemical equilibrium. Microscopic processes still occur and rate of process is balances by reverse process. Process Any change from one state to another steady-flow process operating for long periods of time under the same conditions state postulate a thermodynamic state of a simple compressible sysem is completely specified by two independent, intensive properties cycle a process with identical end states Pressure Force/Area. absolute pressure measured relative to absolute zero (absolute vacuum)P abs = P atm +/- P gage atmospheric pressure aka gage or vacuum pressure Temperature energy content of a mass heat (Q) transfer; the difference in temperature that causes energy to flow between bodiesAlso difference in enthalpy! zeroth law of thermo if two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other Phase physically homogeneous/mechanically separable part of system (i.e. vapor, liquid, mineral) component Expresses compositional variations in system. H20 is one-component system, only if phases are interest Energy states Unstable: falling/rollingStable: at rest in LOWEST energy stateMetastable: in low-energy perchequilibrium is NOT steady state thermal equilibrium No net transfer of energy as heat between two regions contacted by diathermic wall (same temp). Different temp, heat would flow from hot to cold region. Mechanical Equilibrium Two regions separated by a wall have equal pressure. But if one region had high pressure, it would move the wall toward the region with low pressure. reversible Idealized process, proceeds through sequence of equilibrium states. No finite deviation from equilibrium. spontaneous real/natural process where internal state of system changes to approach equilibrium from initial non-equilibrium state Endothermic absorbs heat (+Q, or delta H > 0 ) Exothermic releases heat (-Q, or delta H < 0) AuthorKatieMac ID4937 Card SetThermo, set 1 DescriptionChemical Thermodynamics Updated2010-03-13T14:56:05Z Show Answers