1. CHAPTER 16 SOLUTIONS

2. Theme of the Chapter Solutions vs. Pure Liquids

3. Henry’s law as the pressure of the gas above the liquid increases, so does the solubility of a gas in the liquid ex: carbonated soda ex: carbonated soda

4. Henry’s Law As Pressure increases As Pressure increases Solubility increases Solubility increases This is a direct proportion This is a direct proportion

5. Henry’s Law ex 1: If the solubility of a gas in water is.77g/L at 350 kPa of pressure, what is the solubility, in grams per liter at 100 kPa of pressure?

6. Molarity 1. Tells how concentrated a solution is. 2. the # of moles of solute dissolved in 1L of solution

8. Molarity ex1: How many moles of solute are present in 1.5L of.20M Na 2 SO 4 ? -we are looking for moles of solute

9. How to Make Dilutions If you have a solution and the molarity is too high, you need to dilute the solution to lower the molarity (concentration). Use this equation to make a more dilute solutiion:

10. How to Make Dilutions Ex 1: How would you prepare 200. mL of 0.60M MgSO 4 from a stock solution of 3.0 M MgSO 4 ? The dilute solution is 0.60M MgSO 4, and we want to make 200.mL of it. The dilute solution is 0.60M MgSO 4, and we want to make 200.mL of it. The concentrated solution is 3.0M MgSO 4. The concentrated solution is 3.0M MgSO 4. We need to remove some of this stock solution and then add some distilled water to it to dilute it. So, lets figure out how much distilled water to add. M 1 V 1 = M 2 V 2 = (200.mL)(.60M) = (3.0M)(V 2 ) V 2 = 40mL therefore, V 2 = 40mL therefore, 1. you would take 40mL of the stock solution (3.0M), and since we need 200mL, 2. you would add 160mL (200mL -40mL = 160mL) of distilled water in order to make a.60M solution of distilled water in order to make a.60M solution So, now we have 200.mL of our dilution 0.60M solution

11. How to Make Dilutions 1. Add 40 mL of stock to empty container stock solution 3.0M MgSO 4 Dilute solution 0.60M MgSO 4 2. Add 160 mL of distilled water to empty container (need 200mL, added 40 mL, need 160 mL to top off)

12. Colligative Properties How are solutions different from pure liquids? When you add a solute to a liquid the Freezing point, Boiling point, and Vapor Pressure of the solution change

13. Water: The freezing point of pure water is 0°C. The normal boiling point of water is 100°C. But if you make a solution using water as the solvent, the freezing point of that solution will not be 0°C nor will the boiling point be 100°C. A SALT WATER SOLUTION: The freezing point will be lower than 0°C, boiling point will be higher than 100°C, & the vapor pressure will decrease. Colligative Properties

14. So… 1. Freezing point depression 2. Boiling point elevation 3. Vapor pressure lowering Colligative Properties

16. Vapor Pressure Lowering The pressure over a liquid or solution that results when molecules escape the liquid and enter the gaseous phase. In order for a molecule in the liquid phase to enter the gaseous phase, the molecule must be at the surface of the liquid and have enough kinetic energy to break the surface. The addition of a nonvolatile hinders this situation in two ways: In order for a molecule in the liquid phase to enter the gaseous phase, the molecule must be at the surface of the liquid and have enough kinetic energy to break the surface. The addition of a nonvolatile hinders this situation in two ways: The solute particles occupy space at the surface. The solute particles occupy space at the surface. The solute particles introduce a new set of attractive forces with the solvent molecules. The solute particles introduce a new set of attractive forces with the solvent molecules.

17. The more dissolved solute the greater the changes. The more dissolved solute the greater the changes. Ex: the more salt you add to salt water the higher the Boiling Point, the lower the vapor pressure and freezing point Ex: the more salt you add to salt water the higher the Boiling Point, the lower the vapor pressure and freezing point Which will have a higher boiling point? Which will have a higher boiling point? 1M solution of CuCl 2 vs. 1M solution C 6 H 12 O 6 1M solution of CuCl 2 vs. 1M solution C 6 H 12 O 6 1M solution of CuCl 2 Because there are more ions in solution that hold onto the water molecules

18. Freezing Point Depression

19. Vapor Pressure Lowering