Chapter 6 Solutions and Colloids

1. Chemistry B11 Chapter 6 Solutions and Colloids

2. Mixtures Mixture:is a combination of two or more pure substances. Homogeneous: uniform and throughout Air, Salt in water Solution Heterogeneous: nonuniform Soup, Milk, Blood

3. Solutions Gas in gas (air) solid in solid (alloys) liquid in liquid (alcohol in water) Gas in liquid (cokes) solid in liquid (sugar in water) Solutions Well-mixed (uniform) – single phase homogenous transparent cannot be separated by filtration cannot be separated on standing sugar in water

4. Immiscible: two liquids do not mix. alcohol in water miscible: two liquids can mix. (in any quantities) Solutions (liquid in liquid) Solvent: greater quantity (water) Solute: smaller quantity (sugar) for liquid in liquid

5. Supersaturated:solvent holds more solute that it can normally hold (at a given T). (more than an equilibrium condition) Solutions Saturated:solvent contains or holds all the solute it can (at a given T). maximum solute that solvent can hold (Equilibrium). Unsaturated:solvent can hold more solute (at a given T). Is not the maximum solute that solvent can hold.

6. T  Solubility  Crystal is formed T  Temperature and Solutions Solubility:the maximum solute that will dissolve in a given amount of a solvent (at a given T).

7. T  Solubility  Temperature and Solutions Supersaturated solution Seeding A surface on which to being crystallizing.

8. Solubility ↓ gas in liquid: T ↑ Global Warming

9. Pressure and Solutions Henry’s law P  Solubility  (gas in liquid)

10. Concentration Concentration:amount of a solute dissolved in a given quantity of solvent. 1. Percent concentration: Weight solute × 100 Weight / volume (W / V)% = Volume of solution (mL) Weight solute × 100 Weight / Weight (W / W)% = Weight of solution Volume solute (mL) × 100 Volume / volume (V / V)% = Volume of solution (mL)

11. Concentration 2. Molarity (M): number of moles solute dissolved in 1 L of solution. moles solute (n) Molarity (M) = volume of solution (L) Molarity × V = number of moles (n) prepare the solution: M, V → n (mol) → m (g)

12. m (g) Volumetric flask Prepare the solution prepare the solution: M, V → n (mol) → m (g)

13. Concentration 3. Parts per Million (ppm): g solute ppm = × 106 g solvent Parts per billion (ppb): g solute ppb = × 109 g solvent

14. Dilution Dilute solution Concentrated solution (Stock solution)

15. Dilution M1V1 = moles(n) before dilution M2V2 = moles(n) after dilution M1V1 = M2V2 % V1 = % V2

16. Equivalent Number of Equivalents (Eq) in 1 mole of each ion is number of charges of that ion.

17. Equivalent Ex. 1: How many equivalents of CO32- are in 1 mole of Al2(CO3)3? The charge of CO32- is 2- → 1 mole Al2(CO3)3 has 2 Eq CO32-. Ex. 2: How many equivalents of Fe3+ are in 5 mole of Fe2O3? The charge of Fe3+ is 3+ → 1 mole Fe2O3 has 3 Eq. 5 moles: 5 × 3 = 15 Eq

18. Water in our body • About 60% of our body. • Most of the reactions occur in aqueous solution. • Participates in many biochemical reactions. • Transports reactants and products from one place in our body to another. 5. Eliminates the waste materials from cells and our body (urine).

19. Ions Hydrated by H2O Hydration Solvent and Solute polar dissolves polar Nonpolar dissolves nonpolar like dissolves like

20. Solvent and Solute All nitrates (NO3-) and acetate (CH3COO-) are soluble in water. Most chlorides (Cl-) and sulfates (SO42-) are soluble in water. (except AgCl, BaSO4, and …) Most carbonates (CO32-), phosphates (PO43-) and hydroxides (OH-) are insoluble in water. (except NaOH, LiOH, KOH, and NH4OH)

21. electrolyte + - Electrolytes bulb Electrolyte:conducts an electric current. Na+ Cl- Ionization (Dissociation) NaCl → Na+ + Cl- strong electrolytes:molecules dissociate completely into ions (NaCl). weak electrolytes:molecules dissociate partially into ions (CH3COOH). nonelectrolytes:molecules do not dissociate into ions (DI water).

22. Colloids Solutions:diameter of the solute particles is under 1 nm. Colloids:diameter of the solute particles is between 1 to 1000 nm. non transparent, non uniform, large particles, cloudy (milky) but a stable system

23. Colloids Tyndall effect: You can see the pathway of the light passes through a colloid. (particles scatter light.) emulsion:a mixture of immiscible substances (liquid-liquid). (milk and mayonnaise)

24. Suspension suspension:system does not stays stable and settle (> 1000 nm). (sand in water)

25. Brownian motion Random motion of colloid particles. Dust Why do colloidal particles remain in solution and do not stick together? 1. Surrounding water molecules prevent colloidal molecules from touching and sticking together. 2. A charged colloidal particle encounters another particle of the same charge, they repel each other.

26. Freezing and boiling point bp  fp  If we dissolve a solute in a solvent: ΔT: change of bp or fp (T2 - T1) i: number of particles K: constant (depend on solute) – Kb Kf M: molarity ΔT = ikM NaCl  Na+ + Cl- i = 2 K2SO4 2K+ + SO42- i = 3 C2H6O2 i = 1

27. Osmotic Pressure osmotic pressure Semipermeable membrane Higher concentration → Higher osmotic pressure

28. Osmotic Pressure Water flows from low concentration to high concentration.

29. Osmotic Pressure Osmolarity (osmol) = M × i M: molarity i: number of particles Osmolarity ↑→ Osmotic pressure ↑

30. Isotonic solution Hypotonic solution Hypertonic solution Hemolysis Crenation

31. The most typical isotonic solutions 0.9% (m/v) NaCl 5% (m/v) Glucose 0.9 g NaCl/100 mL of solution 5 g glucose/100 mL of solution Higher than these numbers → Hypertonic solution Lower than these numbers →Hypotonic solution

32. Dialysis Dilute solution