2nd Exam-Colloidal Dispersions Flashcards
Particle size of colloidal dispersion
1 nm - 5 um
Particle size of coarse dispersion
> 0.5 um
T/F Coarse dispersions are microheterogenous
F. Colloidal ang microheterogenous
Example of solid dispersed phase in gas dispersion medium
Solid aerosols, smoke, dust
Example of gas DP in gas DM
wala.
Foams have ___ DP in __ DM
Gas. Liquid
Liquid in solid examples
Absorption bases
Solid in liquid examples
Sols
Visibility of colloidal dispersion
Electron microscope
substances that do not diffuse through a semi-permeable membrane
Colloid
Heterogenous
Lyophobic
Homogenous
Lyophilic
Amphiphiles
Association
how do hydrophilic colloids aquire a charge
Ionization
acid treated gelatin –> charge? pH?
+ 4-4.5
base treated gelatin –> charge? pH?
8
composed of materials that do not have affinity to the dispersion medium & are not solvated (solvent-hating) → due to the absence of solvent sheath around the particle
Lyophobic colloids
characterized by having two distinct regions of opposing solution affinities within the same molecule or ion
association colloids
other name for association colloids
amphiphilic colloids
size of molecular dispersoin
excess surfactant that aggregates in the bulk of the solution
micelle
aggregates that contain 50 or more monomers
micelles
diameter ranges from ____
50 – 80 angstroms
may increase the solubility of poorly water soluble compounds
Micelles
concentration of monomer at which the micelles is formed
Critical Micelle Concentration
number of monomers that aggregate to form a micelle
Aggregation number
T/F In aqueous solutions, the CMC is reduced by the addition of electrolytes
T
colloidal particles appear as tiny points of light in constant motion when examined under an ultramicroscope
Brownian movement
particles are kept dispersed throughout the dispersing medium by random collisions with other molecules
Brownian movement