1. UNIT IX Lesson #3 Like dissolves like! (Miscibility)

2. Polar Vs Non-Polar nonpolar = symmetrical polar = asymmetrical (if one end of the molecule differs from the other) Methane Hydrogen fluoride

3. Which compounds dissolve in what?? Experimentally, it is found that… “LIKE DISSOLVES LIKE” POLAR dissolves------- POLAR ------- IONIC NONPOLAR dissolves ------- NONPOLAR *Miscible = soluble

4. E XAMPLES E X #1: WATER AND CARBON TETRACHLORIDE

5. E XAMPLES E X #2: I ODINE IN WATER

6. E XAMPLES E X #3: I ODINE IN CARBON TETRACHLORIDE

8. E XAMPLES E X #4: SUGAR IN WATER

9. E XAMPLES E X #5: SUGAR IN C ARBON TETRACHLORIDE

11. E XAMPLES E X #6: ETHANOL, CH 3 CH 2 OH Ethanol in water Ethanol in carbon tetrachloride

13. M ETHANOL & ETHANOL CH 3 OH CH 3 CH 2 OH W HICH ONE DO YOU THINK IS SLIGHTLY BETTER AT DISSOLVING NON - POLAR COMPOUNDS ?

14. Common solvents: p.204 Water - the most common polar solvent… Methanol (polar and non-polar ends) Ethanol (polar and non-polar ends) benzene ethoxyethane Acetone ( polar and non polar ends) acetic acid Chloroform carbon tetrachloride (non-polar) heptane liquid ammonia

15. D ISSOLVING PROCESS http://www.northland.cc.mn.us/biology/biology11 11/animations/dissolve.html

17. Why can’t non-polar solvents dissolve ionic compounds? Non-polar solvents can only attach to solutes using London forces ; these forces cannot overcome the strong bonds that hold ionic compounds together Ionic solutes are held by very strong ionic bonds when they are in the solid phase, so they need the most polar solvent, such as water, to dissolve them.

18. HOMEWORK Hebden p. 207 # 18, 19, 20, 22 Hebden p. 208 # 23 (be careful if they are asking for inter or intra molecular forces) #24 ( determine the forces that exist first between the molecules, to decide which is stronger. The stronger= the higher the melting point) #25