a quantity of matter or a region in space chosen for study
physical space outside the system boundary
real or imaginary surface that separates the system from its surroundings. It may be fixed or movable.
exchange of energy but NOT matter
(control volume), exchange of energy and matter
boundary of an open system
can exchange NEITHER energy nor matter
a characteristic of a system in equilibrium. It is independent of the path used to arrive at the system condition.
independent of amount of material (i.e.temperature, pressure, age, color, etc.)
Ratio of two extensive = intensive
Dependent of amount of material (mass, volume, total energy, etc.)
a force. W = mg
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.
Any change from one state to another
operating for long periods of time under the same conditions
a thermodynamic state of a simple compressible sysem is completely specified by two independent, intensive properties
a process with identical end states
measured relative to absolute zero (absolute vacuum)
P abs = P atm +/- P gage
aka gage or vacuum pressure
energy content of a mass
(Q) transfer; the difference in temperature that causes energy to flow between bodies
Also 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
physically homogeneous/mechanically separable part of system (i.e. vapor, liquid, mineral)
Expresses compositional variations in system. H20 is one-component system, only if phases are interest
Stable: at rest in LOWEST energy state
Metastable: in low-energy perch
equilibrium is NOT steady state
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.
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.
Idealized process, proceeds through sequence of equilibrium states. No finite deviation from equilibrium.
real/natural process where internal state of system changes to approach equilibrium from initial non-equilibrium state