Solutions and Colloids



Solutions are homogeneous (evenly distributed) mixtures that form when a solute is dissolved or mixed with a solvent. To form a solution, solute particles must spread apart from one another, and solvent particles must spread apart from one another. Solute and solvent particles must then move together through an attractive intermolecular force. Solute and solvent particles must have similar structures and have intermolecular forces of similar strengths in order to form a homogeneous mixture. Ionic compounds are soluble in water because the high bond energy of ionic crystals is overcome by the hydration energy of the ion-dipole bond (attraction between an ion and a particle with partially charged ends) between ions and water. Colligative properties are a set of solution properties that are affected only by the concentration of the solution (number of particles present in the solution). Colligative properties include freezing point depression, boiling point elevation, vapor pressure reduction, and osmotic pressure. A mixture is a colloid if it is heterogeneous (unevenly distributed) with suspended particles that do not settled.

At A Glance