Colloids

Colloids are mixtures that contain particles that are intermediate in size between those in solutions and suspensions. These particles are larger than the particles in a solution but smaller than those in a suspension.

Types of Colloids

Sol: A colloid in which solid particles are dispersed in a liquid.
Gel: A colloid in which a liquid is dispersed in a solid.
Emulsion: A colloid in which liquid droplets are dispersed in a liquid.
Aerosol: A colloid in which liquid or solid particles are dispersed in a gas.
Foam: A colloid in which gas is dispersed in a liquid.

Properties of Colloids

Particle Size: The particles in a colloid are larger than molecules in a solution but smaller than those in a suspension.
Scattering of Light: Colloidal particles scatter light, making the dispersion appear cloudy or opaque.
Brownian Motion: Colloidal particles exhibit Brownian motion, which is the random movement of particles in a fluid medium.
Stability: Colloids are generally stable and do not settle out on standing, unlike suspensions.

Applications of Colloids

Colloids are widely used in various industries and everyday products, including food (e.g., mayonnaise, milk), medicine (e.g., pharmaceutical formulations), and cosmetics (e.g., lotions, creams).