BOILING AND FREEZING POINT

• Colligative Properties


  Properties dependent on the number of solute particles that are dissolved in a given quantity of the solvent

  
• Colligative Properties


  • Examples are boiling point and freezing point

  
• Adding salt to water


  Increases the boiling point of the solution
• Adding salt to water

  Decreases the freezing point of the solution
• Boiling Point Elevation


  The phenomenon that occurs when the boiling of a liquid (a solvent) is increased when another compound is added, such that the solution has a higher boiling point than the pure solvent

  
• Calculating Boiling Point Elevation

  Consider the molality of the solution

  
• Freezing Point Depression


  The temperature at which water changes form a liquid to a solid at 0 °C or 32 °F, lowered by adding another compound to it
• Calculating Freezing Point Depression

  Consider the molality of the solution

  
• Solution with 4.0 g sucrose in 200 g water


  • Boiling point = 100.03 °C
  • Freezing point = -0.11 °C
• Solution with 15.0 g salt in 750 g water


  • Boiling point = 100.82 °C
  • Freezing point = -0.65 °C
• Adding solute to pure solvents will cause a decrease in freezing point and an increase in boiling point