Chapter 16 Properties of Solutions

• Solution


  Homogenous mixture that may be a solid, liquid or gas
• Factors that determine if a solute will dissolve in a solvent

  • Compaction of solvent
  • Temperature
  • Solubility
• If a substance is insoluble, no amount of stirring will dissolve it
• Stirring will speed up the dissolution rate but does not determine the AMOUNT that a solvent can dissolve
• At higher temperatures


  The kinetic energy of the solvent is greater than at lower temperatures creating more COLLISIONS with the solute
• Many smaller particles have more surface area than 1 large particle. Ex: sugar cube vs. granulated sugar
• Solubility


  The amount of solute that can dissolve in a given amount of solvent at a specific temperature
• Saturated solution


  Contains the maximum number of dissolved solute particles. Adding any more solute will cause some of the solute to crystallize and settle on the bottom of the container. It will not dissolve.
• Unsaturated solution


  Contains more solute that it can theoretically hold. Adding more solute will dissolve.
• Supersaturated solution


  Contains more solute than it can theoretically hold
• Solubility


  The ability of a substance to dissolve in a solvent
• As temperature increases


  The solubility of gases in liquid solvents increases
• As temperature decreases


  The solubility of gases in liquid solvents decreases
• Gases become less soluble in warm water
• Molarity


  A measure of concentration - the number of moles of solute per liter of solution
• Calculating molarity


  Divide the moles of solute by the volume of the solution
• Colligative properties


  Properties of a solution that differ from the pure solvent, and depend on the number of solute particles in the solution
• Important colligative properties


  • Vapor pressure lowering
  • Boiling point elevation
  • Freezing point depression
• Vapor pressure


  The pressure exerted by the vapor of a liquid
• Solutions have lower vapor pressure than pure solvents

  Because solute particles reduce the number of free solvent particles able to escape the liquid
• Freezing point depression


  The freezing point of a solution is lower than the freezing point of a pure substance
• Freezing point depression


  Is directly proportional to the number of solute particles in solution
• Boiling point elevation


  The boiling point of a solution is higher than the boiling point of a pure substance
• Boiling point elevation


  Is directly proportional to the number of solute particles in solution
• Ionic compounds dissociate into more particles in solution than covalent compounds
• Molarity Equation

  M=Moles/Liters
• Molarity and Volume Equation

  MV=MV