Role of Adsorption in Surface Chemistry
For Example: Gages such as H2, O2 , N2 adsorbs on the surface of activated charcoal.
Enthalpy of Adsorption : Amount of heat energy liberated when one mole of gas is adsorbed on the unit surface area of adsorbent is known as enthaply of adsorption.
ADSORPTION
* Adsorption is the phenomenon of attracting and retaining the molecules of substance on the surface of a liquid of solid, resulting in a higher concentration of molecules on the surface.
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* The attachment of particles to a surface is called Adsorption.
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* The phenomenon of concentration of molecules of a gas or liquid at a solid surface is called Adsorption. Adsorption is a surface phenomenon, Adsorption examples Alimina gel, silica gel, zeolites, activated carbon, graphite, finely divided metals, etc are some examples of good adsorbents.
* Adsorbate :- The substance being adsorbed is called adsorbate.
* Adsorbent :- The substance on whose surface it is being adsorbed is called adsorbent.
* Specific surface area :- Surface area of adsorbate per unit mass of adsorbent is known as specific surface area.
* Sorption is a term used when both adsorption and adsorption occur simultaneously.
* Desorption is the reverse of adsorption, i. e. the removal of the adsorbed substance from the surface of the adsorbent.
* Occlusion is a term used for adsorption of gages on a metal surface.
* Positive adsorption occurs when concentration of adsorbate is more on surface of the adsorbent than in the bulk.
* Negative adsorption occurs when concentration of adsorbate on the surface of the adsorbent is less than that in the bulk.
* Physical Adsorption or Physidorption is the process in which the adsorbate particles are held on the surface of adsorbent by weak van der Waal's surface.
* Chemical Adsorption or Chemisorption is the process in which the adsorbate molecules are held by the adsorbent by chemical forces.
Tags:
Adsorbate
Adsorbent
Adsorption
ADSORPTION- Enthalpy of Adsorption
Sorption
Specific surface area