General Terms Flashcards
Adiabatic
Condition of zero heat interaction at system boundaries
Association
Description of complex formation where all molecules in the complex are of the same type
Azeotrope
Mixture which does not change composition upon vapor-liquid phase change
Barotropy
The state of a fluid in which surfaces of constant density (or temperature) are coincident with surfaces of constant pressure
Binodal
Condition of binary phase equilibrium
Dead state
A description of the state of the system when it is in equilibrium with the surroundings, and no work can be obtained by interactions with the surroundings.
Diathermy
Heat conducting, and without thermal resistance, but impermeable to mass
EOS
Equation of State
Heteroazeotrope
Mixture that is not completely miscible in all proportions in the liquid phase and like an azeotrope cannot be separated by simple distillation. The heteroazeotropic vapor condenses to two liquid phases, each with a different composition than the vapor. Upon partial or total vaporization, the original vapor composition is reproduced.
Infinite Dilution
Description of a state where a component’s composition approaches zero
Irreversible
A process which generates entropy
Isenthalpic
Condition of constant enthalpy
Isentropic
Condition of constant entropy
Isentropic efficiency
Ratio characterizing actual work relative to ideal work for an isentropic process with the same inlet (or initial) state and the same outlet (or final) pressure.
Isobaric
Condition of constant pressure
Isochore
Condition of constant volume
Isopiestic
Constant or equal pressure
Isopycnic
Condition of equal or constant density
Isolated
A system that has no interactions of any kind with the surroundings (e.g. mass, heat, and work interactions) is said to be isolated
Isosteric
Condition of constant density
LLE
Liquid Liquid equilibrium
Master Equation
U(V,T)
Measurable Variables
Variables from the set {P, V, T, Cp, Cv} and derivatives involving only {P, V, T},
Meta stable
Signifies existence of a state which is non equilibrium, but not unstable, e.g. superheated vapor, sub cooled liquid, which may persist until a disturbance creates movement of the system towards equilibrium.
Nozzle
A specially designed device which nearly reversible converts internal energy to kinetic energy. See Throttling.
Polytropic Exponent
The exponent n in the expression PV^n = constant
Quality
The mass fraction of a vapor liquid mixture that is vapor
Rdf
Radical distribution function
Reference State
A state for a pure substance at a specified (T, P) and type of phase (S, L, V). The reference state is invariant to the system (P, T) throughout an entire thermodynamic problem. A problem may have various standard states, but only one reference state. See also standard state.
Sensible Heat Changes
Heat affects accompanied by a temperature change
Specific Property
An intensive property per unit mass
SLE
Solid Liquid Equilibria
Solvation
Description of complex formation where the molecules involved are of a different type.
Spinodal
Condition of instability, beyond which meta stability is impossible
Standard Conditions
273.15 K and 0.1 MPa (IUPAC), standard temperature and pressure
Standard State
A state for a pure substance at a specified (T, P) and type of phase (S, L, V). The standard state T is always at the T of interest for a given calculation within a problem. As the T of the system changes, the standard state T changes. The standard state P may be a fixed P or the P of the system. Gibbs energies and chemical potentials are commonly calculated relative to the standard state. For reacting systems, enthalpies and Gibbs.energies of formation are commonly tabulated at a fixed pressure of 1 bar and 298.15 K. A temperature correction must be applied to calculate the standard state value at the temperature of interest. A problem may have various standard states, but only one reference state.
State of aggregation
Solid, liquid, gas
Steady State
Open flow system with no accumulation of mass and where state variables do not change with time inside system boundaries
STP
Standard Temperature and Pressure, 273.15 K and 1 atm. Also referred to as standard conditions
Subcooled
Description of a state where the temperature is below the saturation temperature for the system pressure, e.g., subcooled vapor is metastable or unstable, subcooled liquid is stable relative to the bubble point temperature; superheated liquid is metastable or unstable relative to the dew-point temperature; subcooled liquid is metastable or unstable relative to the fusion temperature.
Superheated
Description of a state where the temperature is above the saturation temperature for the system pressure.
Thermal efficiency
The ratio or work obtained to the heat input to a heat engine. No engine may have a higher thermal efficiency than a Carnot engine.
Thermodynamic Efficieny
Ratio characterizing actual work relative to reversible work obtainable for exactly the same change in state variables for a process. The heat transfer for the reversible process will differ from the actual heat transfer.
Throttling
A pressure drop without significant change in kinetic energy across a valve, orifice, porous plug, or restriction, which is generally irreversible
Unstable
A state that violates thermodynamic stability, and cannot persist
Wet Steam
A mixture of water vapor and liquid
