Simple Distillation

Chemistry

1. CHAPTER 3 Separation and Purification © 2013 Marshall Cavendish International (Singapore) Private Limited

2. 3.1 Obtaining Pure Substances from Mixtures 3.2 Separating a Solid from a Liquid 3.3 Separating Solids 3.4 Separating a Liquid (Solvent) from An Aqueous Solution 3.5 Separating Liquids 3.6 Chromatography 3.7 Determining Purity Separation and Purification Chapter 3 2

3. Learning Outcome describe a method to separate and purify a solvent from a solution. At the end of this section, you should be able to: 3.4 Separating a Liquid (Solvent) from a Solution 3

4. Recall from Chap 4: Aqeuous Solutions are Mixtures. 4 3.4 Separating a Liquid (Solvent) from a Solution SOLUTE

5. Simple Distillation Simple distillation is used to separate a pure solvent (liquid) from a solution . Examples: 5 3.4 Separating a Liquid (Solvent) from a Solution Mixture (Aqueous Solutions) Soluble Solid (Solute) Liquid (Solvent) Sugar solution Sugar (any solute) Water (the solvent) Aqueous potassium bromide Potassium bromide (Ionic Compound) Water (the solvent)

6. Setting Up the Distillation Apparatus Thermometer bulb should be just beside the side arm leading to the condenser. Water enters the condenser from the bottom and leaves from the top. Condenser must be sloping downwards. Boiling chips are placed in the flask to ensure smooth boiling. Volatile liquids can be kept in the liquid state by placing receiver on ice. water in water out 6 3.4 Separating a Liquid (Solvent) from a Solution

7. Simple distillation of salt solution 2. Water boils and becomes vapour. Thermometer measures temperature of the vapour. 3 . Water vapour is cooled and condenses into pure liquid ( distillate ). 5. Pure water is collected as distillate. 4. The salt solution becomes more concentrated as distillation continues. Salt will be collected as residue . 1. Boiling chips are added to ensure smooth boiling . Water vaporises , rises and enters the condenser. 7 3.4 Separating a Liquid (Solvent) from a Solution