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Solutions/Acid & Bases

Solutions/Acid & Bases. Chapter 15 & 19. Solution are homogenous mixtures. Solutions are made up of 2 things: A solute & a solvent. Water is the most common solvent in liquid solutions. Dissolves in a solvent Example: Sugar in water. Will not dissolve in a solvent Example:

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Solutions/Acid & Bases

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  1. Solutions/Acid & Bases Chapter 15 & 19

  2. Solution are homogenous mixtures. • Solutions are made up of 2 things: • A solute & a solvent. • Water is the most common solvent in liquid solutions.

  3. Dissolves in a solvent Example: Sugar in water Will not dissolve in a solvent Example: Sand is insoluble in water. Soluble & Insoluble

  4. Two liquids that are soluble in one another Example: Antifreeze & water Acetic acid & water Two liquids not soluble in one another Example: Oil & vinegar Oil & water Miscible & Immiscible

  5. What gets dissolved. The lesser amount of substance in a solution. Example: Sugar Salt What things dissolve in. The greater amount of substance in a solution. Example: Water Ethanol Solute & Solvent

  6. Solvation • Rules: • Like dissolves like. • Polar dissolves polar. • Nonpolar dissolves nonpolar.

  7. Solvation of salt cont… • Formula units break apart & ions become attracted to charges of the water molecules.

  8. Solvation of salt

  9. Solvation of sugar (covalent) • In polar molecules, water molecules have a stronger attraction to the polar molecules than they have to each other.

  10. “What can affect solubility?” Two factors that affect rates of solutions. • Temperature • Pressure

  11. Surrounding solute particles with solvent particles. Breaking apart. “Dissolving” Hydration Particles coming together. Dehydration Solvation & Crystallization

  12. Max amount of solute dissolves in a solvent at a temp/pres. Ex: Concentrated or strong tea Less solute is dissolved than saturated. It can dissolve more. Ex: Diluted or weak tea Saturated & Unsaturated

  13. Factors that affect solubility 1. Temperature: • For solids- ↑ temperature, ↑ solubility • For gases- ↑ temperature, ↓ solubility 2. Pressure: • For gases in liquid- ↑ pressure, ↑ solubilty

  14. Super saturated solution- a solution that contains more solute than saturated solutions at the same temp/pressure

  15. http://www.youtube.com/watch?v=D1PDE5OawuI&edufilter=iaYy5cltW5JHB2qLmddDPghttp://www.youtube.com/watch?v=D1PDE5OawuI&edufilter=iaYy5cltW5JHB2qLmddDPg

  16. Henry’s Law- at a given temperature, solubility of a gas in a liquid is directly proportional to the pressure of a gas above the liquid. • Example: a soda

  17. 15.2 Solution Concentration • How much solute is dissolved in a specific amount of solvent is concentration

  18. Describing concentration • Qualitative: • Concentrated or diluted

  19. Describing concentration • Quantitative: • Percent by volume • Molarity (M) • Molality • Normality

  20. Molarity: (M)(mol/L)= moles of solute liters of solution

  21. Example 1 • A 100.5 mL intravenous solution contains 5.10 g of glucose (C6H12O6). What is the molarity of this solution? • Hint: glucose molar mass is 180. g/mol. • Practice 1-3

  22. 15-3 Colligative Properties of Solutions • Physical properties that are affected by the number of particles and not by their identity are colligative properties.

  23. Examples of colligative properties include: • 1. vapor pressure lower • 2. boiling point elevation • 3. freezing point depression • 4. osmotic pressure

  24. Solutions: • Solutes will not settle out • Will not scatter light • Cannot filter

  25. 15-4 Heterogeneous Mixtures • Suspensions: • Settles out • Scatters light • Can be separated by filtering • Are large particles (>1000 nm) • Examples: muddy water, fine sand in water

  26. Colloids: • Don’t settle out • Scatters light • Can’t be filtered • Medium to small sizes (<1000 nm) • Examples: milk

  27. Brownian motion is the random movement of colloid particles. • Causes collision of particles preventing them from settling.

  28. Tyndall effect: • Particles scatter light • Can be seen in suspensions & colloids • Examples: ray of light through fog or smoke

  29. Acid & Bases Chapter 19 • Acids, bases, & salts are electrolytes because they conduct electrical current. • An indicator is a compound that changes color to indicate the presences of an acid or base.

  30. Characteristics of acids • Sour taste • Reacts with metals • Neutralizes bases • affects indicators • turns blue litmus red/pink • keeps phenolphthalein colorless • turns methyl orange red

  31. Common Acids: • Citric acid- in citrus fruits • (Lemons, oranges, etc) • Acetic acid- vinegar • Malic acid- apple • Butyric acid- sour butter • Lactic acid- sour milk; builds up in muscles during exercise.

  32. Industrial acids: • Sulfuric acid- (H2SO4) most manufactored chemical in US; fertilizers • Phosphoric acid- (H3PO4) fertilizers; detergents • Nitric acid- (HNO3) fertilizers; explosives • Hydrochloric acid- (HCl) used to “pickle” steel (remove surface impurities)

  33. Review: Naming acids • 1. Binary acids- (only 2 elements) “hydro________ic acid” • Ex. HBr • Ex. H2S • 2. Oxyacids- (has polyatomic ions) “________ic acid” • Ex. HClO3 • Ex. H2SO4

  34. Characteristics of Bases • tastes bitter • feels slimy • affects indicators • pink litmus turns blues • phenolphthalein turns bright pink • methyl orange turns yellow

  35. Common Bases: • Ammonia- (NH3) cleaning agent • Lye- (NaOH) draino • Milk of magnesia- (Mg(OH)2) laxative • Lime- (Ca(OH)2) mortar for bricks, foul lines on fields

  36. What is pH? • pH is the negative logarithm of H+1 ion concentration • pH= -log[H+] • pH range- 014 • pH scale: acids  0-6.99, neutral  7, base  7.01-14

  37. Example 2 • What is the pH of a solution with the concentration [H+]= 1.0 x 10-7 M? • Practice 4. What is the pH of [H+]=1.0x10-2? 5. What is the pH of [H+]=3.0x10-6? pOH? 6. What is the pOH of [OH-]=8.2x10-6?

  38. Ex. 3 What is the concentration (Molarity) of H+ of an acidic solution with the pH of 3.20? • Practice: • 7. Calculate the concentration of H+ of an acidic solution with the pH of 6.55.

  39. Neutralization • Neutralization Reaction- reaction between an acid & base to produce a salt & water • Salt- made of the positive ion (from base) & the negative ion (from acid) • Example: • Mg(OH)2 + HCl  • Practice: • H3PO4 + Ca(OH)2 • Al(OH)3 + H2SO4 

  40. Acid is the sub. containing H Base is the sub. containing OH Ex. HCl & NaOH Acid is the sub. that loses the H+ Base is the sub. that gains the H+. involves conj. acid & bases H2O + NH4+ NH3 + H3O+ Arrhenius vs Bronted-Lowry

  41. Practice: • Identify the following Bronsted-Lowry acids & bases. • HC2H3O2 +H2O  H3O+ + C2H3O2-

  42. Anhydrides are compounds that can become acids or bases when water is added. • Ex. Which is the anhydride? • CO2 + H2O  H2CO3 • Practice. Which is the anhydride? • CaO + H2O Ca(OH)2 • H2O + SO2  H2SO4

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