chapter 12 solutions 12.1 types of mixtures. classification of matter solutions are homogeneous...

Download Chapter 12 Solutions 12.1 Types of Mixtures. Classification of Matter Solutions are homogeneous mixtures!

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  • Slide 1
  • Chapter 12 Solutions 12.1 Types of Mixtures
  • Slide 2
  • Classification of Matter Solutions are homogeneous mixtures!
  • Slide 3
  • Solute A solute is the dissolved substance in a solution. A solvent is the dissolving medium in a solution. Solvent Salt in salt water Sugar in soda drinks Carbon dioxide in soda drinks Water in salt water Water in soda
  • Slide 4
  • Types of Solutions Gaseous mixturesGaseous mixtures Air is a solution Solid solutionsSolid solutions Metal alloys Liquid solutionsLiquid solutions Liquid dissolved in a liquid (alcohol in water) Solid dissolved in a liquid (salt water)
  • Slide 5
  • Concentrated vs. Dilute
  • Slide 6
  • Suspensions and Colloids Suspensions and colloids are NOT solutions. Suspensions: The particles are so large that they settle out of the solvent if not constantly stirred. Particles can be filtered out. Example: Oil & Water Colloids: The particles intermediate in size between those of a suspension and those of a solution. Particles cannot be easily filtered out. Example: Milk
  • Slide 7
  • Slide 8
  • Smoke is a solid in a gas. Fog is a liquid in a gas. Milk of Magnesia is a sol with solid magnesium hydroxide in water Mayonnaise is oil in water Gelatin is protein in water. Quicksand is sand in water
  • Slide 9
  • The Tyndall Effect Colloids scatter light, making a beam visible. Solutions do not scatter light. Which glass contains a colloid? solution colloid
  • Slide 10
  • The ammeter measures the flow of electrons (current) through the circuit. If the ammeter measures a current, and the bulb glows, then the solution conducts. If the ammeter fails to measure a current, and the bulb does not glow, the solution is non-conducting. Electrolytes vs. Nonelectrolytes
  • Slide 11
  • An electrolyte is: A substance whose aqueous solution conducts an electric current. A nonelectrolyte is: A substance whose aqueous solution does not conduct an electric current. Try to classify the following substances as electrolytes or nonelectrolytes Definition of Electrolytes and Nonelectrolytes
  • Slide 12
  • 1.Pure water 2.Tap water 3.Sugar solution 4.Sodium chloride solution 5.Hydrochloric acid solution 6.Lactic acid solution 7.Ethyl alcohol solution 8.Pure sodium chloride Electrolytes?
  • Slide 13
  • Electrolytes:Nonelectrolytes: Tap water (weak) NaCl solution HCl solution Lactate solution (weak) Pure water Sugar solution Ethanol solution Pure NaCl But why do some compounds conduct electricity in solution while others do not?
  • Slide 14
  • Chapter 12 Solutions 12.2 The Solution Process
  • Slide 15
  • Dissolution of sodium Chloride The Hydration Process
  • Slide 16
  • Saturation of Solutions A solution that contains the maximum amount of solute that may be dissolved under existing conditions is saturated. A solution that contains less solute than a saturated solution under existing conditions is unsaturated. A solution that contains more dissolved solute than a saturated solution under the same conditions is supersaturated.
  • Slide 17
  • Slide 18
  • Factors Affecting the Rate of Dissolution Increasing the Surface Area of the SoluteIncreasing the Surface Area of the Solute Finely divided substances dissolve more rapidly Agitating a SolutionAgitating a Solution Stirring or shaking brings solvent into contact with more solute particles Added energy temporarily increases solubility HeatingHeating Heating almost always increasing the rate of dissolution of solids in liquids
  • Slide 19
  • Like dissolves like Polar substances dissolve in polar solventsPolar substances dissolve in polar solvents Nonpolar substances dissolve in nonpolar solventsNonpolar substances dissolve in nonpolar solvents Examples:Examples: Polar and ionic compounds are not soluble in nonpolar solventsPolar and ionic compounds are not soluble in nonpolar solvents Fats, oils and many petroleum products are soluble in nonpolar solventsFats, oils and many petroleum products are soluble in nonpolar solvents Nonpolar solvents include CCl 4 and toluene (methyl benzene), C 6 H 5 CH 3Nonpolar solvents include CCl 4 and toluene (methyl benzene), C 6 H 5 CH 3
  • Slide 20
  • Liquid Solutes and SolventsLiquid Solutes and Solvents Immiscible - Liquid solutes and solvents that are not soluble in each other Ex: Oil and water Miscible - Liquids that dissolve freely in one another in any proportion Ex: Benzene and carbon tetrachloride (both nonpolar) Ex: Water and ethanol (both polar) HydratesHydrates Ionic substances that incorporate water molecules into their structure during the recrystallization process Ex: CuSO 4 5H 2 O
  • Slide 21
  • Slide 22
  • Saturation and Equilibrium The physical state in which the opposing processes of dissolution and crystallization of a solute occur at equal rates
  • Slide 23
  • Effects of Pressure on Solubility Pressure has no real effect on the solubilities of liquids and solids in liquid solventsPressure has no real effect on the solubilities of liquids and solids in liquid solvents Increasing pressure increases the solubility of gases in liquidsIncreasing pressure increases the solubility of gases in liquids Henry's LawHenry's Law The solubility of a gas in a liquidThe solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid EffervescenceEffervescence The rapid escape of a gas from a liquid in which it is dissolvedThe rapid escape of a gas from a liquid in which it is dissolved
  • Slide 24
  • Effects of Temperature on Solubility Solubility of solids increases with temperatureSolubility of solids increases with temperature Solubility of gases decreases with temperatureSolubility of gases decreases with temperature
  • Slide 25
  • Solubility Trends The solubility of MOST solids increases with temperature. The rate at which solids dissolve increases with increasing surface area of the solid. The solubility of gases decreases with increases in temperature. The solubility of gases increases with the pressure above the solution.
  • Slide 26
  • Therefore Solids tend to dissolve best when: o Heated o Stirred o Ground into small particles Liquids & Gases tend to dissolve best when: o The solution is cold o Pressure is high
  • Slide 27
  • Heat of Solution The Heat of Solution is the amount of heat energy absorbed (endothermic, positive) or released (exothermic, negative) when a specific amount of solute dissolves in a solvent. Substance Heat of Solution (kJ/mol) NaOH-44.51 NH 4 NO 3 +25.69 KNO 3 +34.89 HCl-74.84
  • Slide 28
  • Chapter 12 Solutions 12.3 Concentration of Solution
  • Slide 29
  • Molarity (M) The concentration of a solution measured in moles of solute per liter of solution. mol = M L Pronounced molar
  • Slide 30
  • Slide 31
  • Slide 32
  • Molality (m) The concentration of a solution in moles of solute per kilogram of solvent. Since the most common solvent, water, has a density of 1 kg/L, one kilogram of water is the same as one liter of water! m mol = m kg
  • Slide 33
  • Dilutions If a solution of known concentration and volume has been diluted, we can calculate the new concentration:If a solution of known concentration and volume has been diluted, we can calculate the new concentration: M 1 V 1 = M 2 V 2 Example: 20.00 mL of a 0.500 M KBr solution is diluted to 100.00 mL. What is the new molarity? (20.00mL)(0.500M) = (100.00mL)(M 2 ) M 2 =0.100 M Additional practice problems located in Appendix D p. 902

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