(Finals) PhyPharm Lec Quiz 1 Flashcards
The boundary that exists between two
phases.
Interface
The properties of the molecules forming the
interface are often sufficiently different from those in the bulk of
each phase that they are referred to as
forming an
Interfacial phase
Complete
Separate phases; _________________
Boundary; ________________
Bulk phases
Interfacial phases
refers to the force between liquids-vapor and solid-vapor.
Surface tension
Involves vapor/gas as one of the bulk/phases
refers to the force between 2 liquids, between 2 solids and between liquid-solid interface.
Interfacial tension
Between 2 liquids, solids, or liquid and a solid
A phenomenon where the added molecules are partitioned in FAVOR OF THE INTERFACE
Positive adsorption
A phenomenon where the added molecules are partitioned in FAVOR OF THE BULK
Negative adsorption
Example of Positive Adsorption
Surface Active Agents (SAA’s)
Example of Negative Adsorption
NaCl electrolyte and water
Surface Active Agents AKA?
Surfactants or Amphiphilic molecules (amphiphiles)
They are classified to be wetting agents that lowers the surface tension of a liquid, allows easier spreading, and lowers the interfacial tension between two liquids.
SURFACE ACTIVE AGENTS
Surface active agents lower what?
Lowers the surface tension of a liquid
which ALLOWS EASIER SPREADING
Lowers the interfacial tension between two liquids
3 Main Properties of Surfactants
- are Surface Active Agents
- are Emulsifying agents
- reduce Surface tension
What is the head of the surfactant? Hydrophilic/Hydrophobic?
Hydrophilic
What is the tail of the surfactant? Hydrophilic/Hydrophobic?
Hydrophobic
something that brings two things together that do not come together, under normal circumstances.
Emulsifying agents
When surfactants are added to water, they rush to the surface because?
They are surface active agents
Hydrophile-Lipophile Balance (HLB) is devised by who
Griffin
the ratio of the weight percentages of the hydrophilic and hydrophobic groups in an emulsifier.
Hydrophile-Lipophile Balance (HLB)
Low contact angle
Good wetting
Higher contact angle
Bad wetting
Surface Active Agents can be these 3, what are these 3?
Anion (-)
Cationic (+)
Non-ionic (0)
What are the 6 different kinds of surfactants?
- Solubilizing Agents
- Detergents
- O/W Emulsifying agents
- Wetting and Spreading Agents
- Oil in Water Emulsifying Agents
- Most Antifoaming Agents
Emulsifiers with HLB Value: below 9
lipophilic