Surface Chemistry

These flashcards cover key concepts from surface chemistry, focusing on adsorption, colloids, catalysis, and related terms.

Adsorption

The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid.

Adsorbate

The molecular species or substance that concentrates or accumulates at the surface during adsorption.

Adsorbent

The material on the surface of which adsorption takes place.

Physisorption

Physical adsorption where the accumulation of gas on the surface occurs due to weak van der Waals' forces.

Chemisorption

Chemical adsorption where molecules are held to the solid surface by chemical bonds.

Freundlich Adsorption Isotherm

An empirical relationship between the quantity of gas adsorbed by unit mass of solid adsorbent and pressure at a particular temperature.

Desorption

The process of removing an adsorbed substance from a surface on which it has been adsorbed.

Coagulation

The process of changing the colloidal particles in a sol into an insoluble precipitate by adding a suitable electrolyte.

Lyophilic colloids

Colloidal sols directly formed by mixing substances with a suitable liquid, known as liquid-loving colloids.

Lyophobic colloids

Colloids that require special methods to form and are easily precipitated, known as liquid-hating colloids.

Tyndall Effect

The scattering of light by colloidal particles, making the path of the light beam visible in a colloidal solution.

Brownian Movement

The zig-zag motion observed in colloidal particles due to unbalanced bombardment by molecules of the dispersion medium.

Catalyst

A substance that accelerates the rate of a chemical reaction without itself being consumed.

Heterogeneous Catalysis

Catalytic processes where the reactants and the catalyst exist in different phases.

Homogeneous Catalysis

Catalytic processes where the reactants and the catalyst are in the same phase.

Electrophoresis

The movement of colloidal particles under an electric field toward the electrode of opposite charge.

Micelles

Aggregates formed by surfactants at or above a specific concentration, containing both hydrophilic and hydrophobic parts.

Emulsification

The process of forming an emulsion by mixing two immiscible liquids with the help of an emulsifying agent.

Colloid

A heterogeneous system in which one substance is dispersed as very fine particles in another substance.