Solution: a homogenous mixture made up of two or more substances (aka: aqueous). A solution is made up of a solute and a solvent. Solute: a substance like salt or sugar that dissolves in a solvent like water. Solvent: usually a liquid, for example water. If the solvent is water, then the solution is called an aqueous solution (aq). Factors Affecting the Rate of Dissolving Surface area Stirring Temperature Factors Affecting Solubility 1. Temperature: Solids and liquids: as temperature increases, solubility increases Gases: as temperature increases, solubility decreases 2. Nature of Solute/Solvent: “Likes dissolve in likes” Polar solutes will only dissolve in polar solvents Non-polar solutes will only dissolve in non-polar solvents Water is polar (polar= ionic or polar covalent) 3. Pressure: Pressure only has an affect on gases. Has NO affect on solids or liquids. This is how soda maintains its “FIZZ”, once the soda can is opened the CO2 in solution is released into the atmosphere and soda goes “FLAT”. Table G: Solubility Curve HCl NH3 SO2 There are three types of solutions: ◦ saturated ◦ unsaturated ◦ supersaturated The slopes on Table G represent SATURATED!!! Any amount above is supersaturated, any amount below is unsaturated. You can determine how much solute settles out, precipitates, re-crystalizes using this table as well. Soluble or Insoluble? (Table F) Soluble Insoluble Insoluble Soluble Molarity The molarity of a solution is the number of moles of solute in one liter of a solution. Molarity (M) = moles of solute liters of solution Parts Per Million (ppm) A unit of concentration that expresses the mass of a solute dissolved in 1 million parts of a very diluted solution. ppm = grams of solute x 1,000,000 grams of solution Percent by Mass Similar concept as percent composition (part/whole x 100). Looking to calculate the percent mass of solute in the whole solution. % Mass = grams solute x 100 grams solution Boiling Point Elevation: Rule: The presence of a solute (salt or sugar) raises the boiling point of the solvent. Freezing Point Depression: Rule: The presence of any solute (salt or sugar) lowers the freezing point of the solvent. This is how we are able to melt ice from pavement; make ICE CREAM; speed up cooking time when boiling water is required.