Unit 8: Solubility Factors + dissociation Objectives What factors affect solubility What is the difference between Dissolve and dissociate. Words to know Solution Dissolve Soluble Insoluble Dissociate Surface Area

Dissolve vs Dissociate The terms dissolve and dissociate are often used interchangabley (people think they mean the same thing) Anything that dissociates can also be described as dissolving. Anything that dissolve CANNOT always be described as dissociating. The word dissociate (opposite of associate) means to split apart. This means the + and – parts of an ion split from each other. The word dissolve means that the water particles (or other solvent) simply surround the solute (solid) on a molecular/particle level. NaCl can be described as both dissolving and dissociating in water. How about O2 Gas?

Factors Affecting Solubility Solublity describes how well a substance (solute) dissolves in another substance (solvent). We can say that the solubility of NaCl (solute) in water (solvent) is relatively high because NaCl dissolves “well” in water. Anything that dissolve CANNOT always be described as dissociating. Facts: Solubility of solids generally increase with increasing temperature. However, Solubility of Gases decrease with increasing temperature. Why? How would increasing global temperature affect marine life?

Pressure and Surface Area Pressure is a factor that ONLY affects gases. Would Increasing pressure increase or decrease the solubility of a gas? Consider Soda. Surface area is a factor that DOES NOT increase nor decrease solubility. Surface area only affect the rate at which a substance will react/dissolve Consider a 100g sugar cube vs 100g of granulated sugar, which would dissolve faster?