Surface Chemistry

= Adsorption = Adsorption is the process of accumulation of absorbate particles on the adsorbent surface.

Physisorption & Chemisorption
Physisorption is the process of adsorption of particles on a surface by weak Vaan der Waals Forces.

Chemisorption is the process of adsorption of particles on a surface by stronger chemical bonds.

Adsorption of Gases on Solids
x/m = kPn  (where n is 0 for high pressure and n is 1 for low pressure)

Factors Affecting Adsorption
= Catalysis = Catalysis is the process of speeding up a reaction by adding certain specific materials. The phenomenon of Adsorption is useful for Catalysis.

Catalytic Activity
Catalyst makes the chemical reaction easier or faster by reducing it's activation energy or providing a surface for attack of reagent.

Catalytic Selectivity
Catalytic Selectivity refers to the idea that each chemical reaction needs a certain, specific catalyst and that catalysts are not universal.

Enzyme Catalysis
= Colloids =

Types of Solutions
True Solutions

Particle Size = less than 10-10m

Colloidal Solutions

Particle Size = 10-7 to 10-9m

Suspension

Particle Size = More than 10-6 m

Sols
Lyophilic Sols : Liquid loving sols. They can be prepared directly by mixing solid with liquid. Relatively stable as they have affinity for liquid.

Lyophobic Sols : Liquid hating sols. Special methods are employed to prepare lyophobic sols and additional stabilizers are required during their preparation. They are less stable.

Electrophoresis : It is similar to electrolysis.

Surfactants and Micelles
(Only definition and examples)

Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants. are compounds that lower the surface tension (or interfacial tension) between two liquids or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants.

A micelle (/maɪˈsɛl/) or micella (/maɪˈsɛlə/) (plural micelles or micellae, respectively) is an aggregate of surfactant molecules dispersed in a liquid colloid. A typical micelle in aqueous solution forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre.