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CHAPTER 14

CHAPTER 14. SOLUTIONS And Mixtures. Immiscible = 2 liquids that can be mixed but separate shortly after you stop mixing (oil and vinegar) Miscible = two liquids that are soluble in each other (water and antifreeze). Soluble = if a substance dissolves in a solvent (homogeneous)

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CHAPTER 14

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  1. CHAPTER 14 SOLUTIONS And Mixtures

  2. Immiscible = 2 liquids that can be mixed but separate shortly after you stop mixing (oil and vinegar) • Miscible = two liquids that are soluble in each other (water and antifreeze)

  3. Soluble = if a substance dissolves in a solvent (homogeneous) • Insoluble = doesn’t dissolve (heterogeneous)

  4. Mixtures: Heterogeneous • Heterogeneous Mixture: two or more substances physically combined, but is not uniform throughout • Suspension: mixture that contains large particles that will settle out if left undisturbed (oil/vinegar)-can be filtered • Colloid: mixture of intermediate sized particles that will not settle out (like milk, blood)-can’t be filtered • Both disperse light in Tyndell effect

  5. Types of Colloids • Gas dispersed in liquid- foam (whipped cream) • Liquid dispersed in gas (fogs-mist), Liquid dispersed in liquid (emulsion-milk, mayo,blood) • Solid dispersed in gas (smokes), liquid dispersed in liquid (gelatin)

  6. Tyndell effect (light is reflected off the particles in the mixture)

  7. Mixtures: SOLUTION • DEF = homogeneous mixture containing two or more substances , uniform throughout (solute dissolved in a solvent)

  8. Solvation = the process of surrounding solute particles with solvent particles to form a solution Video “like dissolves like”

  9. TYPES OF SOLUTIONS • GAS IN GAS = AIR • GAS IN LIQUID = SODA • LIQUID IN GAS= humid air • LIQUID IN LIQUID = ANTIFREEZE (ethylene glycol/water) VINEGAR (acetic acid/water) • SOLID IN LIQUID= OCEAN WATER (salt/water) • LIQUID IN SOLID= DENTAL FILLING(Ag in Hg) • SOLID IN SOLID= STEEL (Fe in Carbon) • GAS IN A SOLID – pop rocks (mythbuster) (spangler)

  10. SOLUBILITY • Def= the maximum amount of solute that will dissolve in a given amount of solvent at a specific temperature and pressure • Three types of solutions: • Saturated • Unsaturated • supersaturated

  11. SATURATED SOLUTION • Contains the maximum amount of dissolved solute for a given amount of solvent

  12. UNSATURATED SOLUTION • Contains less dissolved solute than a saturated solution (more solute can still be dissolved)

  13. SUPERSATURATED SOLUTION • Contains more solute than a saturated solution, made by increasing the temperature and allowing the solution to cool slowly • Very unstable • Example: rock candy

  14. SEEDING IN A SUPERSATURATED SOLUTION Sodium acetate seeding Sodium acetate sculptures

  15. For those about to dissolve, we solute you

  16. FACTORS AFFECTING SOLUBILITY • TEMPERATURE- as temperature increases the solubility of a gas solute decreases • Note: most solids increase in solubility w/an increase in temperature • PRESSURE- the solubility of a gas in a solvent increases as it’s external pressure increases • ex: fizz keeper/soda

  17. Mentos and diet soda • Experiment 2- domino effect • Mythbusters explain • Merry Blastmus (mythbusters) • Why?: It’s a process called "nucleation," in which the particular chemistry of the Mentos candy (mint kind, not-glazed) interacts with the chemistry of the carbonated Diet Coke, causing the carbon dioxide gas, or CO2, to suddenly come out of suspension in the liquid and make a break for freedom. (diet coke instead of regular- no sugary mess for the ants will be left behind)

  18. moles M = Moles of solute liters Liters of solvent MOLARITY (M) • Def = concentration of a substance • Used to express the ratio between solute and solvent • Specifically, molarity is the ratio between:

  19. Remember: 1000ml = 1 L = 1000cm3 = 1 dm3 • 1. Grams to Molarity What is the molarity of a solution if you dissolved 35.2 g of NaCl in 500.0 ml of H2O? Steps: 1. first find molar mass of solute: NaCl = 58.5 g/mole

  20. 35.2 g NaCl 1 mole NaCl 58.5 g NaCl = 1.20 M or 1.20 mole/liter 2. Convert grams to moles 3. use M = mole/liter (convert if needed) .602 mol M = .602 mole .5000 L

  21. = .18 moles • 2. Molarity to grams How many grams of KBr do you need to make 250 ml of a 0.725 M solution? Steps: 1. convert molarity to moles M = mole liter .725 M = mole .25 L

  22. .18 mole 119.1 g 1 mole • 2. convert moles to grams (molar mass of KBr = 119.1 g/mole) = 21 g

  23. .10 mol 111.1 g = 11 g 1 mol PREPARING SOLUTIONS • 1. Going from molarity to grams (review) How many grams of CaCl2 would be dissolved in 1.0 L of a 0.10 M solution? M = mole liter .10 M = mol = .10 mol 1.0 L

  24. 2. DILUTION: using concentrated stock solutions and diluting them down to other concentration needed • The total number of moles does NOT change during dilution

  25. M = mole/V • moles (concentrate) = M1V1 • moles (dilute) = M2V2 • Moles concentrate =moles diluted So Dilution formula M1V1 = M2V2

  26. What volume of a 3.00 M KI solution would you need to make 0.300 L of a 1.25 M KI solution? • V1 = ? V2 = .300 L M1V1 = M2V2 M1 = 3.00 M M2 = 1.25 M (3.00 M)(V1) = (1.25 M)(.300 L) V1 = (1.25 M) (.300 L) = 0.125 L OF 3.00 M KI 3.00 M So: You would add .125 L of 3.00M KI to .175 L of water to make a 1.25 M solution

  27. FREEZING POINT DEPRESSION • As a pure solvent reaches freezing point, the molecules KE slows down and the attractive forces between particles take over • It freezes

  28. BUT…….. • When a solute is mixed in, the solute particles interfere w/the attractive forces, preventing the solvent from freezing at its normal point (lowers the freezing point) • FREEZING POINT DEPRESSION = the difference in temp. between a solution’s freezing point and the freezing point of the pure solvent • Simulation • http://www.worsleyschool.net/science/files/saltandfreezing/ofwater.html

  29. Types of road salt • Making Ice Cream (spangler)

  30. How its made- ice cream treats • http://www.youtube.com/watch?v=SiICaHAOrGE

  31. BOILING POINT ELEVATION • When a pure solvent reaches its boiling point it has enough kinetic energy to break free from the attractive forces and atmospheric pressure • BUT….when a solute is added to the solution it must be heated to a higher temp. to supply the additional kinetic energy for the solution to boil

  32. BOILING POINT ELEVATION = the temp. difference between a solution’s boiling point and a pure solvent’s boiling pt. • Simulation

  33. Quest • 12 multiple choice/short answer • Know vocab • Solution types • Ways to increase/decrease solubility • 4 calculations • Grams to molarity • Molarity to grams • Dilution • Formulas/periodic table will be given

  34. Song- For those about to dissolve- we solute you • Review quiz • Hangman • Jeopardy

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