Mixtures and Solutions

1. Mixtures and Solutions

2. Types of Mixtures • Heterogeneous – • Homogeneous

3. Heterogeneous mixtures • Suspensions – • Particle size:

4. Colloids – • Particle size: • Brownian motion: • Tyndall effect:

6. Homogeneous Mixtures • Solutions • Solute • Solvent • Can be solid, liquid, or gas

7. Soluble - • Insoluble - • Miscible - • Immiscible -

8. Solution Concentration • Measure of how much solute is dissolved in a specific amount of solvent or solution • Qualitative: Concentrated vs. Dilute • Quantitative: % by mass, % by volume, Molarity

9. % by mass: • In order to maintain a sodium chloride concentration similar to ocean water, an aquarium must contain 3.6 g NaCl per 100.0 g of water. What is the percent by mass of the NaCl in the solution?

10. You have 1500.0 g of a bleach solution. The percent by mass of the solute (NaOCl) is 3.62%. How many grams of NaOCl are in the solution?

11. % by volume – used when both solute and solvent are liquid

12. What is the percent by volume of ethanol in a solution that contains 35mL of ethanol dissolved in 155 mL of water? • What is the percent by volume of isopropyl alcohol in a solution that contains 24 mL of isopropyl alcohol in 1.1 L of water?

13. Molarity (M) • What is the molarity of a solution containing 3 moles of solute in 1.5 L of solution?

14. What is the molarity of 155 mL of solution containing 1.55 g dissolved KBr?

15. Preparing molar solutions • How many grams of CaCl2 would be dissolved in 1.0 L of a 0.10 M solution of CaCl2?

16. What mass of NaOH is in 250 mL of a 3.0 M NaOH solution?

17. Diluting molar solutions: • What volume of 2.00M CaCl2 stock solution would you use to make 0.50L of 0.300M CaCl2 solution?

18. How many mL of 5.0 M H2SO4 stock solution would you need to prepare 100.0 mL of 0.25M H2SO4?

19. Factors Affecting Solvation • Temperature • Pressure • Polarity

20. Solvation Process • To form a solution solute particles must separate and the solute and solvent particles must mix • Solvent particles surround surface of the solid solute • Forces between solute and solvent > forces holding solute together

21. Solvation -

22. Ways to increase solvation • Increase collisions between solute and solvent particles • Agitation • Increase surface area • Increase temperature

23. Solubility • Unsaturated solutions • Saturated solutions • Supersaturated solutions

25. Solubility of gases – less soluble at higher temperatures • http://youtu.be/HaDNWZuYKfw

26. Pressure & Henry’s law – solubility of a gas increases as pressure increases

27. Colligative Properties of Solutions • Colligative properties depend on number of solute particles in a solution

28. Vapor pressure lowering – • Vapor pressure: • Adding a nonvolatile solute to a solution lowers the solvent’s vapor pressure

29. Boiling point elevation – • Boiling point • Because vapor pressure is lowered, boiling point increases

30. Freezing point depression – solute particles interfere with attractive forces holding solvent particles together

31. Osmotic Pressure • Osmosis – • Additional pressure caused by water molecules that moved into the concentrated solution