PHA 317 Exam 2 Interfacial Phenomena Questions with Correct Answers Latest Update
2025/2026
adsorption - Answers primarily a surface phenomenon
absorption - Answers occurs throughout th entire bulk of a substance
surface active agents, surfactants, or amphiphies - Answers molecules that can be adsorbed
and reduce surface tension.
what must be present on a molecule for it surface to have activity? - Answers the molecule
must be hydrophilic group (facing the bulk) and lipophilic group (facing the air)
micelles - Answers clusters of molecules in the bulk of the solution. these are formed when the
surface and of liquid is fully saturated. this minimize interfacial energy
monomers - Answers individual molecules on the surface of the liquid
how can micelles solubilize lipophilic drugs? - Answers the interior of a micelle is lipophilic
(assuming molecules are in a aqueous solution), this lipophilic center can trap lipophilic drugs
and because like dissolves like the drug can solubilize
critical micellar concentration (CMC) - Answers The concentration above which the monomers
of surfactant start associating to form micelles
CMC and water properties - Answers before CMC is reached surface properties of the liquid
(surface and interfacial tension, vapor pressure) are affected. after CMC is reached bulk
properties of the liquid (density, conductivity) are affected.
how can you use micelles to suspensions and emulsions? - Answers lipophilic core of micelles
can be used to solubilize drug molecules in solutions and suspensions. The core can also be
used to solubilize droplets of oil that is ordinarily immiscible in water.
HLB (hydrophile-lipophile balance) - Answers a measurement tool for surface activity. The
higher the HLB of an agent, the more hydrophilic it is. According to this classification, Spans, or
sorbitan esters, have low HLB values of 1.8 to 8.6, whereas Tweens, or polyoxyethylene
derivatives of spans, are hydrophilic and have high HLB values of 9.6 to 16.7.
solid-gas adsorption - Answers used in the removal of objectionable odors from rooms or food,
operation of gas masks, and measurement of dimensions of particles in a powder.
solid-liquid adsorption - Answers used in decolorizing solutions, adsorption chromatography,
detergency, and wetting.
what affects solid-gas adsorption? - Answers the physical and chemcial nature of the adsorbent
(the material used to adsorb the gas), and the adsorbate (the substance being adsorbed)
2025/2026
adsorption - Answers primarily a surface phenomenon
absorption - Answers occurs throughout th entire bulk of a substance
surface active agents, surfactants, or amphiphies - Answers molecules that can be adsorbed
and reduce surface tension.
what must be present on a molecule for it surface to have activity? - Answers the molecule
must be hydrophilic group (facing the bulk) and lipophilic group (facing the air)
micelles - Answers clusters of molecules in the bulk of the solution. these are formed when the
surface and of liquid is fully saturated. this minimize interfacial energy
monomers - Answers individual molecules on the surface of the liquid
how can micelles solubilize lipophilic drugs? - Answers the interior of a micelle is lipophilic
(assuming molecules are in a aqueous solution), this lipophilic center can trap lipophilic drugs
and because like dissolves like the drug can solubilize
critical micellar concentration (CMC) - Answers The concentration above which the monomers
of surfactant start associating to form micelles
CMC and water properties - Answers before CMC is reached surface properties of the liquid
(surface and interfacial tension, vapor pressure) are affected. after CMC is reached bulk
properties of the liquid (density, conductivity) are affected.
how can you use micelles to suspensions and emulsions? - Answers lipophilic core of micelles
can be used to solubilize drug molecules in solutions and suspensions. The core can also be
used to solubilize droplets of oil that is ordinarily immiscible in water.
HLB (hydrophile-lipophile balance) - Answers a measurement tool for surface activity. The
higher the HLB of an agent, the more hydrophilic it is. According to this classification, Spans, or
sorbitan esters, have low HLB values of 1.8 to 8.6, whereas Tweens, or polyoxyethylene
derivatives of spans, are hydrophilic and have high HLB values of 9.6 to 16.7.
solid-gas adsorption - Answers used in the removal of objectionable odors from rooms or food,
operation of gas masks, and measurement of dimensions of particles in a powder.
solid-liquid adsorption - Answers used in decolorizing solutions, adsorption chromatography,
detergency, and wetting.
what affects solid-gas adsorption? - Answers the physical and chemcial nature of the adsorbent
(the material used to adsorb the gas), and the adsorbate (the substance being adsorbed)
