Chapter 4 Solutions


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Chapter 4 Solutions

  1. 1. Chemical Interactions <ul><li>Chapter 4: Solutions </li></ul>
  2. 2. Section 4.1 A Solution is a Type of Mixture
  3. 3. The parts of a solution are mixed evenly. <ul><li>A solution is a homogeneous mixture: all portions have identical properties. </li></ul><ul><li>The solute is the substance that is dissolved. </li></ul><ul><li>The solvent dissolves the solute. </li></ul>
  4. 4. Page 112 <ul><li>Solutes, solvents, and solutions can be liquids, solids, or gases. </li></ul><ul><li>The solute and solvent can be in the same or in different physical states. </li></ul>
  5. 5. Page 113 <ul><li>A suspension is a mixture with large particles. </li></ul><ul><ul><li>The particles do not dissolve. </li></ul></ul><ul><ul><li>The mixture is not a solution. </li></ul></ul>
  6. 6. Solvent and solute particles interact. <ul><li>When a solid dissolves in a liquid, the solute breaks apart. </li></ul><ul><li>Solute particles are surrounded by solvent particles and are evenly distributed in the solution. </li></ul>
  7. 7. Page 114
  8. 8. Page 114 <ul><li>Ionic compounds break up into individual ions when they dissolve. </li></ul><ul><li>When covalent compounds dissolve, the molecules separate from each other, but covalent bonds remain intact and the individual molecules remain whole. </li></ul>
  9. 9. Properties of solvents change in solutions. <ul><li>A solute changes the physical properties of a solvent. </li></ul><ul><ul><li>The freezing point of a solution is lower than the freezing point of the pure solvent. </li></ul></ul><ul><ul><li>The boiling point of a solution is higher than the boiling point of the pure solvent. </li></ul></ul>
  10. 10. Section 4.2 The Amount of Solute That Dissolves Can Vary.
  11. 11. A solution with a high concentration contains a large amount of solute. <ul><li>The concentration of a solution is the amount of solute dissolved in it at a particular temperature. </li></ul><ul><li>Solutions can be made more concentrated by adding solute. </li></ul><ul><li>Solutions can be made more dilute by adding more solvent . </li></ul>
  12. 12. Page 118 Degrees of Concentration Low Solubility High Solubility
  13. 13. Page 118 <ul><li>A saturated solution holds as much of a given solute as it can at a given temperature. </li></ul><ul><ul><li>If it holds more solute than normal, it is supersaturated . </li></ul></ul><ul><ul><ul><li>Very unstable </li></ul></ul></ul><ul><ul><ul><li>Disturbing the solution could cause excess solute to come out of the solution as a precipitate. </li></ul></ul></ul>
  14. 14. Page 119
  15. 15. Page 119 <ul><li>Every substance has a characteristic solubility , the amount that will dissolve in a certain amount of a certain solvent at a given temperature. </li></ul>
  16. 16. The solubility of a solute can be changed. <ul><li>Changes in temperature will change the solubility. </li></ul>
  17. 17. Page 121
  18. 18. Page 122 <ul><li>The solubility of liquid and solid solutes are not usually affected by changes in pressure. </li></ul>
  19. 19. Solubility depends on molecular structure. <ul><li>Solubility depends on changes of solute particles. </li></ul><ul><li>Molecules with regions of electrical charge (polar molecules) and ions dissolve in polar solvents such as water. </li></ul><ul><li>Nonpolar molecules (oils) do not have charged regions and do not dissolve in polar solvents, but they dissolve in nonpolar solvents. </li></ul>
  20. 20. Page 123
  21. 21. Section 4.3 Solutions can be Acidic, Basic, or Neutral
  22. 22. Acids and bases have distinct properties. <ul><li>Acids: </li></ul><ul><ul><li>A substance that can donate a hydrogen ion to another substance when the acid is dissolved in water. </li></ul></ul><ul><ul><ul><li>HCl is an acid and donates a H + ion in a water solution. </li></ul></ul></ul>
  23. 23. Page 126 <ul><li>Acids also: </li></ul><ul><ul><li>Taste sour </li></ul></ul><ul><ul><li>React with carbonates to form CO 2 . </li></ul></ul><ul><ul><li>React with many metals. </li></ul></ul><ul><ul><li>Turn litmus red. </li></ul></ul><ul><li>Common acids: </li></ul><ul><ul><li>Milk, beer, cheese, sauerkraut, wine, vinegar, lemon juice </li></ul></ul>
  24. 24. Page 126 <ul><li>Bases: </li></ul><ul><ul><li>A substance that can accept a hydrogen ion from another substance. </li></ul></ul><ul><ul><li>In water, the base NaOH releases a hydroxide ion, which can accept a hydrogen ion. </li></ul></ul>
  25. 25. Page 126 <ul><li>Bases also: </li></ul><ul><ul><li>Taste bitter </li></ul></ul><ul><ul><li>Feel slippery or soapy </li></ul></ul><ul><ul><li>Turn litmus blue. </li></ul></ul><ul><li>Common bases: </li></ul><ul><ul><li>Borax, milk of magnesia, ammonia, oven cleaner, peroxide </li></ul></ul>
  26. 27. The strength of acids and bases can be measured. <ul><li>Strong acids and bases break apart completely into individual ions. </li></ul><ul><ul><li>No complete molecules of the acid or base remain in the solution </li></ul></ul>
  27. 28. Page 129 <ul><li>Weak acids and bases don’t break apart completely into ions. </li></ul><ul><ul><li>It contains both molecules of the acid/base and its ions. </li></ul></ul>
  28. 29. Page 128 <ul><li>The acidity of a solution is measured on the pH scale. </li></ul><ul><ul><li>Acids produce higher hydrogen ion concentration and have a low pH – from 0 – 7. </li></ul></ul><ul><ul><li>Bases produce a low hydrogen ion concentration and have a high pH – from 7 – 14. </li></ul></ul><ul><ul><li>Solutions of pH 7 are neutral. </li></ul></ul>
  29. 30. Acids and bases neutralize each other. <ul><li>When an acid and base come into contact, they undergo a neutralization reaction. </li></ul><ul><ul><li>The hydrogen ion from the acid and the hydroxide ion from the base combine to form water. </li></ul></ul><ul><ul><li>The negative ion from the acid and the positive ion from the base combine to form a salt. </li></ul></ul><ul><ul><li>The products of a neutralization reaction – water and salt – are both neutral substances. </li></ul></ul>
  30. 31. Section 4.4 Metal Alloys are Solid Mixtures
  31. 32. Humans have made alloys for thousands of years. <ul><li>Alloy: a solid mixture that has many of the characteristics of a solution. </li></ul><ul><ul><li>In an alloy, a solid (usually a metal) solute is mixed with a solid metallic solvent. </li></ul></ul><ul><ul><li>Made by melting the metal components and mixing them in the liquid state. </li></ul></ul><ul><ul><li>The physical properties of the alloy are different from those of the solvent metal. </li></ul></ul>
  32. 33. Page 135 <ul><li>Two types of alloys: </li></ul><ul><ul><li>Substitutional alloy: atoms of one metal are replaced by the other metal (brass). </li></ul></ul><ul><ul><li>Interstitial alloy: (Steel) Carbon atoms occupy the gaps between the iron atoms. </li></ul></ul>
  33. 34. Page 135
  34. 35. Alloys have many uses in everyday life. <ul><li>Automotive - pistons, cylinder blocks and liners, sliding bearings, wheels. </li></ul><ul><li>Aerospace - actuators and gears, structural elements, bearings and wheels, gas turbines. </li></ul><ul><li>Oil, gas and chemical - valves, pumps, hydraulic and pneumatic systems. </li></ul><ul><li>Cookware - frying pans, saucepans, knife sharpeners. </li></ul><ul><li>Medical - prostheses. </li></ul><ul><li>Printing - anilox rolls. </li></ul>