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Regents Review

Regents Review. Unit 9 – Gas Laws Unit 10 – Solutions Unit 11 – Acids & Bases Unit 12 – Equilibrium. Gas Laws. Chapter 14. Ideal Gas. Don’t exist Model to explain behavior of all gases Review 1 mole of ANY gas occupies 22.4L of volume at STP. Kinetic Molecular Theory.

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Regents Review

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  1. Regents Review Unit 9 – Gas Laws Unit 10 – Solutions Unit 11 – Acids & Bases Unit 12 – Equilibrium

  2. Gas Laws Chapter 14

  3. Ideal Gas • Don’t exist • Model to explain behavior of all gases • Review • 1 mole of ANY gas occupies 22.4L of volume at STP

  4. Kinetic Molecular Theory • The particles in a gas are constantly moving in rapid, random, straight-line motion. • Gas particles have no volume compared to the volume of the gas. • No attraction between particles • All collisions are completely elastic

  5. Boyle’s Law • Relationship between pressure and volume • Constant Temperature and amount of gas • Mathematical relationships • As pressure is increasing, volume is decreasing • As pressure is decreasing, volume is increasing

  6. P V Boyle’s Law

  7. Example • The pressure of a 25 L sample is changed from 2 atm to 0.4 atm. What is the new volume of the gas? • P1V1 = P2V2 • (2atm)(25L) = (0.4atm)V2 • V2 = 125 L

  8. Charles’s Law • Relationship between volume and temperature • Constant Pressure and amount of gas • Mathematical relationships • As temperature is increasing, volume is increasing • As temperature is decreasing, volume is decreasing • Temperature must be in Kelvin

  9. V T Charles’s Law

  10. Example • A gas occupying 45L at 27°C is cooled until its volume is 15L. What is the new temperature of the gas?

  11. Gay-Lussacs'sLaw • Mathematical relationships • As temperature increases, pressure increases • As temperature decreases, pressure decreases • Also known as Gay-Lussac’s Law • Temperature must be in Kelvin

  12. P T Gay-Lussacs'sLaw

  13. Combined Gas Law • Combines Boyle’s, Charles’s, and Gay-Lussacs'sLaws together

  14. Example • A gas at 5atm is heated and compressed from 10L at 100K to 5L at 200K. What is the new pressure?

  15. Example • A gas at 2atm and 27°C occupies 10L of space. What is the new volume when it is cooled to STP?

  16. Avogadro’s Law • Equal volumes of gas at the same Temperature and Pressure have the same number of particles • At the same temperature and pressure, which sample contains the same number of moles of particles as 1 liter of O2(g)? (1) 1 L Ne(g) (3) 0.5 L SO2(g) (2) 2 L N2(g) (4) 4 L H2O(g)

  17. Ideal Gases • Ideal Gases follow assumptions of the Kinetic Molecular Theory • When do real gases act most like an ideal gas? • High Temperature • Low Pressure • When do real gases act least like an ideal gas? • Low Temperature • High Pressure

  18. Solutions and Solubility Chapters 15, 16 Reference Tables F, G

  19. Solution • Homogeneous Mixture • Uniform Throughout • Solvent • Dissolving medium in mixture • Solute • Dissolved particles in solution • Aqueous Solution • Solution with water as the solvent • NaCl(aq)

  20. Solubility • measure of the amount of solute (how much) that can dissolve in a given quantity of solvent at certain conditions • Affected by Temperature, Pressure, and Chemical Nature • Soluble • Solute will dissolve in solvent • Insoluble • Solute will not dissolve in solvent

  21. Temperature • increasing temperature increases solubility of solids and liquids in other solids and liquids • decreasing temperature increases solubility of gases in liquids • Ex: Cold soda is fizzy

  22. Pressure • Increasing partial pressure of gas above liquid increases solubility of the gas in the liquid • Example • Soda Bottles

  23. Chemical Nature • “Like dissolves Like” • Polar and ionic substances will dissolve in polar solvents • Nonpolar substances will dissolve in nonpolar solvents

  24. Dissolving Speed • Stirring • stirring increases speed of dissolving • Temperature • Increasing temperature increases speed of dissolving solids and liquids • Particle Size • decrease particle size or increase surface area, increase speed of dissolving

  25. Table G • Shows the relationship between temperature and amount of solute for a number of different compounds

  26. Types of Solution • Saturated • maximum amount of solute for a given quantity of solvent • At Equilibrium • Unsaturated • contains less than the maximum amount of solute • Supersaturated • Contains more solute than it can theoretically hold

  27. Solution Types • Saturated • On the line • Unsaturated • Under the line • Supersaturated • Above the line

  28. Electrolytes • Compounds that conduct an electrical current when dissolved or in a molten state (melted) • Ionic compounds • NaCl, KNO3, HCl

  29. Dissolving vs. Dissociation • Dissolving • Molecules separate as solvent molecules mix • C6H12O6(s) + H2O(l)  C6H12O6(aq) • Dissociation • Ions separate as solvent molecules mix • NaCl(s) + H2O(l)  Na+(aq) + Cl-(aq)

  30. Separating Mixtures • Mixtures can be separated based on their physical properties • Boiling Pt, Freezing Pt, Density, Molecular Polarity, Particle Size • Process Examples • Filtering, Distillation, Evaporation, Crystallization, Chromatography, Desalination, Extraction

  31. Molarity • Molarity = Moles of Solute Liters of Solution • 1 mol/L = 1 M • Often used for solids dissolved into liquids • Most common concentration system

  32. Molarity Example • What is the molarity of 2 moles of glucose dissolved in 5 Liters of solution? • Molarity = Moles of Solute Liters of Solution

  33. Example • How many moles of HCl are dissolved in 4L of a 3M solution of HCl? • Molarity = Moles of Solute Liters of Solution

  34. Percent Composition • Percent Comp = Part x 100% Whole

  35. Example • A solution contains 80g of NH4Cl in a 1000g solution, what is the percent by mass composition of this solution?

  36. Example • A solution contains 60 mL of NH3 in a 1 Liter solution, what is the percent by volume composition of this solution?

  37. Parts Per Million (ppm) • Used for very small concentrations • ppm = grams of solute x 1,000,000 grams of solution • Units = ppm

  38. ppm example • A 2 kg bar of silver contains 0.05 g of gold, what is the parts per million concentration of gold in the silver bar? 25 ppm Au

  39. Colligative Properties of Solutions • Properties of a solution that depend only on the number of particles dissolved • Vapor Pressure • Boiling Point • Melting Point • Added solute particles get in the way of the solvent molecules changing the above properties

  40. Colligative Properties of Solutions • Adding more solute particles to pure solvent decreases vapor pressure • Adding more solute particles to pure solvent increases boiling point • Adding more solute particles to pure solvent decreases freezing point

  41. Number of Particles • When a covalent compound dissolves the compound stays intact. • When an ionic compound dissociates the compound splits into its ions. • More particles, larger change in property

  42. Acids and Bases Chapter 19 Reference Tables K, L, M

  43. Electrolyte • A substance that conducts an electrical current when melted or in solution • Ionic compounds • Acids and bases

  44. Acid-Base Theories • Arrhenius • Acid • Compounds that ionize to produce hydrogen ions (H+) in aqueous solutions • Examples: HCl, HBr, H2SO4,CH3COOH • Base • Compounds that ionize to produce hydroxide ions (OH-) in aqueous solutions • Examples: KOH, NaOH, LiOH

  45. Acid - Base Theories • Bronsted-Lowry • Acid • Hydrogen ion donor • Base • Hydrogen ion acceptor • Lewis • Acid • Accepts a pair of electrons • Base • Donates a pair of electrons

  46. Acid-Base Theory Lewis Arrhenius Bronsted- Lowry

  47. Properties • Acids • Taste Sour • Will change color of acid – base indicator • Can be strong or weak electrolytes in an aqueous solution • Bases • Taste Bitter • Feel Slippery • Will change color of acid – base indicator • Can be strong or weak electrolytes in an aqueous solution

  48. Ionization • Electrolytes will dissociate into ions when dissolved in water • Strong Electrolytes will completely dissociate • Weak Electrolytes will only partially dissociate

  49. Ionization of Water • Water can be split into 2 ions • H+ and OH- • Ionization of Water • H2O  H+ + OH- • H2O + H2O  H3O+ + OH-

  50. Strong Acids • Completely dissociate when in solution • HCl(s) H+(aq) + Cl-(aq) • HNO3(s) H+(aq) + NO3-(aq)

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