Solution Formation Learning Targets: What is solubility? What factors affect the rate of dissolving?

List all factors you can think of that affect the formation of solutions.

Main Idea Factors such as

Formation of Solution In a solution forces hold the solute and the solvent particles together. Dissolving takes place at the of the solid. Solvation Clip

Formation of a solution Water molecules separate the and the from the ionic crystal. Once separated, the cations get surrounded by the end of the water molecules, and the anions are surrounded by the end of the water molecules.

Formation of Solution The interaction between solute and solvent particles is called solvation. If water is the solvent, the interaction is hydration. Separation of solute particles & solvent particles – Attraction of solvent particles – exothermic The overall energy change that occurs during solution formation is called the

Factors Affecting Solvation The rate at which a solid solute dissolves in a solution depends of 3 factors:

Stirring: Stirring a solute up the solution process. Surface Area: Surface Area ↑, Ex: sugar dissolves faster than cubed sugar. Stirring: Stirring a solute up the solution process. Temperature: the temperature of a solvent increases the at which the solute dissolves.

Solubility The amount of that will dissolve in a specific solvent under given conditions. Whether or not a solute will dissolves in a solvent and the extent to which it dissolves depends on . Solubility depends on the nature of the

Solubility - Saturation are solutions that contain less dissolved solute for a given temperature and pressure than a saturated solution. contain the maximum amount of dissolved solute for a given amount of solute at a specific temperature and pressure.

A contains more dissolved solute than a saturated solution at the same temperature. To form a solution, a saturated solution is formed at high temperature and then slowly cooled. Supersaturated solutions are .

Factors influencing Solubility:

Nature of solute and solvent Polar solutes dissolve in Example: water and salt (or any ionic compd.) Nonpolar solutes dissolve in Example: grease and turpentine, cholesterol and fat

Temperature Gases in liquids Solids in liquids Temperature , solubility of a gas Solids in liquids Temperature , solubility of a solid

Pressure Pressure does affect solids and liquids. Gas in liquid: Pressure of solvent , solubility of a gas Henry’s law states that at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P).