Gel

Definition

A gel is a semi-solid system in which a liquid is dispersed within a solid network, forming a three-dimensional structure. Gels exhibit properties of both solids and liquids.

5 Must Know Facts For Your Next Test

1. Gels are classified as colloidal systems where the dispersed phase is liquid and the continuous phase is solid.
2. The formation of gels involves the process of gelation, where molecules in the liquid phase form a network structure.
3. Common examples of gels include gelatin desserts, toothpaste, and certain types of medical dressings.
4. Gels can exhibit thixotropic properties, meaning they become less viscous when shaken or agitated.
5. The stability of gels can be influenced by factors such as temperature, pH, and the presence of electrolytes.

Review Questions

• What phases are present in a gel?
• How does temperature affect the stability of gels?
• Give two examples of common substances that are considered gels.

Related terms

Colloid: A mixture where one substance is dispersed evenly throughout another at microscopic or nanoscopic scales without settling out.

Gelation: The process by which molecules in a liquid form a network structure to create a gel.

Thixotropy: A property of certain gels or fluids that become less viscous when subjected to shear stress, such as shaking or stirring.