Phase Rule and Phase Equilibrium Flashcards
(19 cards)
Phase
homogeneous and physically disinct zone of a system that is separated from other zones of the same system by overlapping surfaces
Phase transition
Spontaneous conversion of one phase to another phase
Characteristic temperature for a given pressure
Components
Smallest number of constituents that can describe the composition of each phase in the system at equilibrium in the form of a chemical formula
Ice, iiquid and water = 1
Degrees of freedom
Least number of intensive variables
Intensive properties
Independent of mass
Temperature, pressure, specific volume, density
Extensive property
Varies directly with mass
Mass and total volume
Gaseous system
2 degrees of freedom
Vapor curve
OA
Sublimation curve
OC
Melting point curve
OB
Critical sollution
Maximum temperature at which the two phase region can exist
Tie line
Separate into phases o constant composition (conjugate phases)
Critical temperature
temperature above which a gas cannot exist in liquid form
Critical pressure
Pressure required to liquefy a gas at critical temperature
Eutectic mixture
A mixture of two elements which has a lower melting temperature than any of its constituents
Eutectic point
Smallest melting temperature of any possible mixture of two compounds
Solid dispersions
eutectic mixtures
intimate cyrstalline mixtures of one component in the other
Ternary systems/diagrams
Oil, water and alcohol component amount
Application of phase diagrams
Prepare solid dispersion and increase solubility and dissolution of poorly soluble drugs
Mixing on solid with another
Determine ratio at which a single liquid phase of two or three liquid phase can be achieved
