1. Chapter 12 topics Google-youtube: How Osmosis works Osmosis Demo Osmosis.mp4 Egg osmosis hypertonic vs hypotonic solution Seven Seas Water Seawater Reverse Osmosis Animation How detergents remove oil Henry‘s law (Henry’s Law)Bends USCG Medical emergency (Colloidal suspensions): Tyndell effect (Colloidal suspensions): Tyndell effect (english) Solutions, suspensions, and colloids What are colloids? Mr. Wizard Supermarket Science

2. Like dissolves like Polar solutes such as NH 3 are usually more soluble in polar solvents such as H 2 O than in non-polar solvents such as gasoline or mineral spirits. Non-Polar solutes such as motor oil are usually more soluble in non-polar solvents such as gasoline than in polar solvents such as water or methanol (wood alcohol). Determine the polarity of NH 3, CO 2, SO 2, CH 4, C 6 H 6 and H 2 O. Which compounds are more soluble in water? ANS: NH 3 and SO 2 are more soluble in water. Gogle-youtube: Like dissolves like. What does this mean? Water- universal solvent.

3. Raoult Raoults’s law: The vapor pressure of a solution is directly proportional to the solute mole fraction. The picture right shows vaporization in a pure liquid. Vapor pressure is Established when condensation rate = vaporization rate. NOTE: Boiling occurs when vapor Pressure = atmospheric pressure.

4. Raoult Adding a solute like antifreeze to a pure liquid like water will depress the freezing temperature (mp. < 0 o C). Solute (black) molecules prevent liquid (water) molecules from combining and freezing. The amount of freezing point depression is related to the number (moles) of solute molecules and is used to determine the molar mass of the solute.

5. Surface Tension Forces surround molecules within a liquid such as water but NOT at the surface. Surface tension arises from these sideways forces. Detergent companies also try to find molecules that are non polar at one end and polar (or ionic ) at the other end. WHY? HINT: Like dissolves like.

6. Osmosis Osmosis the movement of a solvent from a low concentration to high concentration.

7. Colloid - tyndell effect A colloid is finely divided substance in a dispersing medium. Sometimes they are macroscopic charged particles dispersed in a medium(upper picture). The tyndell effect (lower picture) distinguishes colloids(b)from solutions(a).

8. Henry’s Law Henry’s law: The solubility of gas in a liquid is directly proportional to the gas pressure above a liquid. The gas below the piston becomes more soluble in the liquid as the pressure increases.