14-3 Factors Affecting Solution Formation The process of a solvent surrounding and dissolving a solute is called solvation…solvation in water is called hydration. The overall energy or heat energy change that occurs during solution formation is called heat of solution.

Factors That Affect Solution Formation Agitation Surface area Temperature Nature of solutions…soluable?

Solubility A solution that does not have all the solute it can hold at a temperature is unsaturated. A solution that has all the solute it can hold at a temperature is saturated. A solution that has more solute than it should have at a certain temperature is supersaturated.

Henry’s Law Solubility and pressure are directly proportional. S1 = S2 P1 P2 Solubility and pressure are directly proportional. Example: The solubility of a gas over water at 1.0 atm of pressure is .8 g/L. What is the solubility of the gas over water at 3.0 atm of pressure?

14-4 Colligative Properties The properties of a solution are different than those of the pure solvent…these changes are called colligative properties. Ionic compounds split into parts to multiply colligative properties. Molecular compounds do not split into parts and they count only as 1 particle.

Colligative Properties (Cont’d) Vapor pressure lowering. Boiling point elevation. See page 500 for chart. * DTb=K b m Freezing point depression. See page 502 for chart. * DTf=K f m

Osmotic Pressure Osmosis is the movement of a solvent (often water) through a semi-permeable membrane, from a higher concentration to a lower concentration. The additional pressure caused by the water that moves into the space with higher concentration is called osmotic pressure.