Surface Chemistry is the study of phenomena occurring at the interface between two phases.
Key Concepts
Adsorption
- Adsorbent: The solid or liquid on whose surface adsorption occurs.
- Adsorbate: The substance adsorbed on the surface.
- Types:
- Physical adsorption: Weak Van der Waals forces, reversible.
- Chemical adsorption: Strong chemical bonds, irreversible.
- Factors affecting adsorption:
- Nature of adsorbent and adsorbate
- Temperature
- Pressure or concentration
- Langmuir adsorption isotherm: Mathematical equation describing adsorption at constant temperature.
Catalysis
- Catalyst: Substance that alters the rate of a reaction without being consumed.
- Types:
- Homogeneous: Catalyst and reactants are in the same phase.
- Heterogeneous: Catalyst and reactants are in different phases.
- Enzyme catalysis: Biological catalysts, proteins.
Colloids
- Dispersed phase: Substance present in small quantity.
- Dispersion medium: Substance present in large quantity.
- Types:
- Lyophilic: Solvent loving.
- Lyophobic: Solvent hating.
- Properties:
- Brownian motion
- Tyndall effect
- Electrophoresis
- Coagulation: Process of converting a colloidal solution into a precipitate.
- Hardy-Schulze rule: Coagulating power of an ion is directly proportional to its charge.
Emulsions
- Emulsion: Stable mixture of two immiscible liquids.
- Types:
- Oil in water (O/W): Oil droplets dispersed in water.
- Water in oil (W/O): Water droplets dispersed in oil.
- Emulsifying agents: Substances used to stabilize emulsions.
Applications
- Drug delivery
- Water purification
- Heterogeneous catalysis
- Detergents and soaps
- Food industry
Remember to practice numerical problems and diagrams to reinforce your understanding.
