Solubility Notes

1. Solubility Notes Chemistry 5/5/14

2. Drill • Use the table from pg. 10 to give the amount of substances that will dissolve in 100 g of H2O: • NH3 at 10°C and 80°C • Why does solubility of NH3 decrease at higher temperatures? • KCl at 10°C and 70°C • If 50 g of KCl were dissolved in 100 g of water, and it was cooled to 50°C, what kind of solution would you have? • HW: Back of pg. 5 (Cross out “Henry’s Law” and #9)

3. Objectives • IWBAT • List factors that increase rate of solution. • List factors that increase degree of solubility. • Explain dissolution of a solid in a liquid. • Define suspension, colloid, and emulsion.

4. Like dissolves like. • Substances with similar bonds dissolve into each other. • Polar & Polar • Water and Isopropanol (Rubbing Alcohol) • Polar & Ionic • Water and most Salts (NaCl, CaCl2, KI, etc.) • Nonpolar & Nonpolar • Nail Polish and Nail Polish Remover • Oil Paint and Terpentine

5. Oil - No charge on the molecule H H O Water - Separation of Charge Why doesn’t oil dissolve in H2O? • Oils are non-polar molecules. • Water is a polar molecule. • Molecules with unlike bonds do not dissolve into each other.

6. Animation of Salt Dissolving

7. Describe NaCl dissolving in H2O • Water is a dipole. • NaCl dissociates into Na+ ions and Cl- ions. • The - end of the H2O molecule is attracted to the Na+ ion in the salt crystal and pulls it into the water. • The + end of the water is attracted to the Cl- ion.

8. http://nobel.scas.bcit.ca/chem0010/unit9/9.4_solubilityionic.htmhttp://nobel.scas.bcit.ca/chem0010/unit9/9.4_solubilityionic.htm

9. http://nobel.scas.bcit.ca/chem0010/unit9/9.4_solubilityionic.htmhttp://nobel.scas.bcit.ca/chem0010/unit9/9.4_solubilityionic.htm

10. YOU ANSWER • What are the different ways to buy juice? • If you watered down a drink, what would you be doing?

11. Dilution and Solutions • Dilute vs. Concentrated: • Dilute – small amount of solute, large amount of solvent • Concentrated – small amount of solvent, large amount of solute • Molarity -- the measurement of the number of moles of solute per liter of solvent • M = n / V • M -- molarity • n -- number of moles • V -- total volume of solution

12. Mixtures that are like Solutions, but aren’t Solutions! • Suspension • Mixture where particles eventually settle to the bottom • Particles are MUCH bigger than a solution. They may be visible • ex. Chocolate is suspended in hot chocolate or chocolate milk • ex. Tiny particles of dirt (silt) are suspended in river or pond water

13. Like Solutions, but not, cont. • Colloid • Mixture containing particles of a size between suspension and true solution • The particles are not actually dissolved, but also not as large as a suspension’s particles. • Particles remain dispersed (do not settle out), but not dissolved: • may appear cloudy: ex. fog, aerosols, smoke, plain milk • may appear as something between two phases: ex. Jell-o

14. Suspension, Colloid, Solution (L to R) A Solution’s particles DON’T reflect light - looks clear! Notice that the particles have settled out of the Suspension A Colloid’s particles reflect light http://dl.clackamas.cc.or.us/ch105-03/similar.htm

15. Like Solutions, but not, cont. • Emulsions • Colloidal dispersions of liquid in liquid • Tiny particles of one liquid dispersed in another liquid, but NOT dissolved. • These are held together by an emulsifier: • An emulsifier causes two immiscible liquids to mix because one end is polar and one is nonpolar. • ex. egg in mayonnaise, soap in soapy water

16. Soap Molecule Soap molecules immersed in grease stain Nonpolar molecule of grease

17. The End! How many solutions do you think you encounter on a daily basis?