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### Water Notes

1. 1. Water<br />The Universal Solvent<br />
2. 2. Water Walk<br />10 Different pictures/scenarios with brief description<br />Write Down Number of Station and the scenario you are looking at. <br />Start at the number of the station you are at<br />Move clockwise<br />Answer the following questions for each…<br />How does the structure of water relate to this action/scenario?<br />
3. 3. A little bit about water<br />Water is the biological medium on Earth<br />Universal Solvent<br />Solvent: the substance that the solute (salt) is dissovled in (water)<br />Solute: substance (salt) that is dissolved in a liquid<br />Solution: when solutes are uniformly distributed throughout a water solvent<br />All living organisms require water more than any other substance<br />Most cells are surrounded by water, and cells themselves are about 70-95% water<br />The abundance of water is the main reason the Earth is habitable<br />
4. 4. The Solvent of Life<br />A solution is a liquid that is a homogeneous mixture of substances<br />A solvent is the dissolving agent of a solution<br />The solute is the substance that is dissolved<br />Water is a versatile solvent due to its polarity<br />An aqueous solution is one in which water is the solvent<br />
5. 5. Mixture, Solutions and Suspensions…oh my!<br />
6. 6. <ul><li>Mixtures
7. 7. physically, not chemically mixed compounds
8. 8. Not necessarily evenly distributed
9. 9. Homogenous
10. 10. Evenly distributed
11. 11. Cannot see the different parts
12. 12. Heterogenous
13. 13. Not uniformly distributed
14. 14. you can see the parts
15. 15. Solution
16. 16. Homogenous Mixture
17. 17. components are uniformly distributed
18. 18. Solutes and solvents
19. 19. Ex. Salt water
20. 20. Suspension
21. 21. Mixture of water and non-dissolved material
22. 22. Some of the most biologically important substances are both solutions and suspensions
23. 23. Ex. blood</li></li></ul><li>
24. 24. Water<br />Chemical Formula <br /><ul><li>H2O</li></ul>How water is formed<br /><ul><li>Covalent compound
25. 25. Which atom has a stronger pull for electrons?</li></ul>The one that is bigger…oxygen<br />Electrons are shared but they spend more time around Oxygen atom than the hydrogen atoms<br />This makes water a…<br />Polar Molecule<br /><ul><li>Uneven sharing of electrons
26. 26. slight positive charge by hydrogens
27. 27. Slight negative charge by oxygen
28. 28. POLARITY
29. 29. What do opposites do?</li></ul> Water molecules are attracted to other water molecules to form HYDROGEN BONDS<br /><ul><li>Weak attraction between hydrogen atom of one molecule and an oxygen, nitrogen or sulfur bond of another molecule.</li></li></ul><li>LE 3-2<br />
30. 30.
31. 31.
32. 32. Properties of water<br />Versatility as a solvent<br />Cohesiveand Adhesivebehavior<br />Expansion uponfreezing<br />Temperaturemoderation<br />
33. 33. Water as the Universal Solvent<br />Water is an effective solvent because it readily forms hydrogen bonds <br />When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules, a hydration shell<br />Water can also dissolve compounds made of nonionic polar molecules<br />Even large polar molecules such as proteins can dissolve in water if they have ionic and polar regions<br />
34. 34. LE 3-6<br />–<br />Na+<br />+<br />–<br />+<br />–<br />+<br />–<br />–<br />Na+<br />–<br />+<br />+<br />Cl–<br />Cl–<br />+<br />–<br />–<br />+<br />–<br />+<br />–<br />–<br />
35. 35.
36. 36. LE 3-7a<br /> Lysozyme molecule<br />in a nonaqueous environment.<br />
37. 37. LE 3-7b<br />Lysozyme molecule in a aqueous environment.<br />
38. 38. Transpiration:<br />Evaporation of water through the leaves of plants<br />“stomata” are the tiny pores in the leaves of plants through which water (and oxygen) escapes…carbon dioxide enters here…<br />
39. 39. Cohesive and Adhesivebehavior<br /><ul><li>Cohesion: whensimilarmolecules stick together (droplet of water)</li></ul>hydrogen bonds hold water molecules together<br />Cohesion helps the transport of water against gravity in plants<br /><ul><li>Adhesion: whenunlikemolecules stick together (water on glass)</li></ul>Adhesion of water to plant cell walls also helps to counter gravity<br /><ul><li>How does water getfromroots to the leaves of a talltree?</li></li></ul><li>Capillary Action<br />DEF: The movement of water within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension<br />Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules. <br />
40. 40. Capillary Action<br />Think of what happens when you dip a paper towel in water<br />What happens when you put celery in colored water<br />
41. 41. Cohesion accounts for SURFACE TENSION<br />Surface tension is a measure of how hard it is to break the surface of a liquid<br />
42. 42. Heat and Temperature<br />Kinetic energy is the energy of motion<br /><ul><li>Heat is a measure of the total amount of kinetic energy due to molecular motion
43. 43. Temperature measures the intensity of heat due to the average kinetic energy of molecules</li></li></ul><li>Expansion Upon Freezing<br />Liquid H2O WATER!<br />Molecules of a liquid move how?<br />Slide past each other!<br />Hydrogen bonds between water molecules keep breaking and reforming<br />Solid H2OICE!<br />Hydrogen bonds become stuck on whatever nearby water molecule they are attached to<br />Now molecules cannot slide past each other…therefore, they CANNOT pack densely together<br />Liquid water is more dense, therefore…<br />ICE FLOATS!!!<br />
44. 44.
45. 45.
46. 46. What Happens When Hydrogen Bonds Form Between Water Molecules?<br /><ul><li>ENERGY is Released!!!
47. 47. Energy=HEAT
48. 48. So…when water freezes, is energy released or absorbed?
49. 49. RELEASED!
50. 50. When water freezes, its warms up its surroundings.</li></li></ul><li>What Happens When Hydrogen Bonds Between Water Molecules Break???<br /><ul><li>This REQUIRES ENERGY!!!
51. 51. Energy or HEAT MUST Be absorbed
52. 52. To break hydrogen bonds, you just need to add heat…</li></li></ul><li>Moderation of Temperature<br />Water absorbs heat from warmer air and releases stored heat to cooler air<br />Water can absorb or release a large amount of heat with only a slight change in its own temperature<br />
53. 53. Weather and Water<br />Coastal Areas<br />During the hot day, the ocean/lake will absorb energy from the air so that it feels cooler<br />At night, when the air is cooler, the water releases all the stored energy, making it warmer at night<br />“moderate” temperature<br />Inland areas (no water nearby)<br />During the hot day, there is NO water to absorb heat so it is realllllyy hot (think desert)<br />At night, no energy is release, so it gets very cold<br />
54. 54. Water’s High Specific Heat<br />The specific heat of a substance is the amount of heat that must be absorbed or lost for 1 gram of that substance to change its temperature by 1ºC<br />Water’s high specific heat minimizes temperature fluctuations to within limits that permit life<br />Heat is absorbed when hydrogen bonds break<br />Heat is released when hydrogen bonds form<br />
55. 55. Evaporative Cooling<br />Evaporation is transformation of a substance from liquid to gas<br />Heat of vaporization is the heat a liquid must absorb for 1 gram to be converted to gas<br />As a liquid evaporates, its remaining surface cools, a process called evaporative cooling <br />Evaporative cooling of water helps stabilize temperatures in organisms and bodies of water<br />“Sweating” liquid to gas requires heat…this heat comes from inside our body<br />What does the saying “It’s not the heat, it’s the humidity”mean?<br />Humidity: water vapor in the air<br />If there is more water in the air, it is harder for water molecules to evaporate off your skin…so how do you feel?<br />Hot and sticky!<br />
56. 56. Types of Attractions<br />Covalent<br />Ionic<br />Hydrogen<br />Van der Waals Forces<br />Intermolecular force of attraction<br />Due to uneven sharing of electrons in covalent bonds<br />Slight attraction between oppositely charged regions of molecules that are closely packed together<br />Holds large molecules together<br />
57. 57. Hydrophilic and Hydrophobic Substances<br />A hydrophilic substance is one that has an affinity (likes!) for water<br />A hydrophobic substance is one that does not have an affinity (does NOT like; scared of) for water<br />
58. 58. How water acts in solution<br />Occasionally a water molecule dissociates (breaks up) into ions <br /> H2O H+ + OH-<br />This happens to every one water molecule in a million in pure water…not very common<br />The H+ immediately reacts with another water molecule in the solution to make a HYDRONIUM ion H30+<br />
59. 59. Acids and Bases<br />What do you know?<br />
60. 60. Acids<br /><ul><li>An acid is any substance that increases the H+ concentration of a solution
61. 61. ADDS H+ ions to water
62. 62. taste sour
63. 63. turn cabbage juice red
64. 64. turn blue litmus paper red
65. 65. Strong acids (LOW pH)
66. 66. Dissociate completely in water
67. 67. Adds LOTS of H+ ions
68. 68. Hydrochloric acid HCl
69. 69. HCl H+ and Cl-
70. 70. Weak Acids (pH slightly below 7)
71. 71. Partially dissociate in water
72. 72. Only add a little bit of H+ ions
73. 73. Coffee, tomato juice, acetic acid</li></ul>  H         O        |       //H--C—C<br />        |              H         O-<br />CH3COOH = CH3COO- + H+<br />
74. 74.
75. 75. Bases<br />A base is any substance that reduces the H+ concentration of a solution<br />ADDS HYDROXIDE ions (OH-) to water<br />OH- ions bind to any free H+ ions to make…a molecule of water<br />This does what to the concentration of H+ ions ion the water?<br />DECREASE H+ ion concentration, therefore, making it basic<br />Characteristics:<br />taste bitter <br />feels slimy <br />turns cabbage juice yellow, green or blue depending upon the solution concentration <br />turns red litmus paper blue <br />Strong Bases (pH High- close to 14)<br />Completely dissociate in solution<br />Adds LOTS of OH- ion to solutions<br />NaOH sodium hydroxide NaOH Na+ and OH-<br />Weak Bases<br />Partially dissociate in water <br />Adds only a few OH- to solution<br />Ammonia NH3<br />
76. 76.
77. 77.
78. 78. Strong Acids and Bases<br />HCl - hydrochloric acid <br />HNO3 - nitric acid <br />H2SO4 - sulfuric acid <br />HBr - hydrobromic acid <br />HI - hydroiodic acid <br />HClO4 - perchloric acid<br />LiOH - lithium hydroxide <br />NaOH - sodium hydroxide <br />KOH - potassium hydroxide <br />RbOH - rubidium hydroxide <br />CsOH - cesium hydroxide <br />DISSOCIATE COMPLETELY<br />What do you notice?<br />
79. 79. The pH Scale<br /><ul><li>The pH of a solution is determined by the relative concentration of hydrogen ions H+
80. 80. So it is really measuring how acidic something is
81. 81. formula is..
82. 82. pH=-log[H+]
83. 83. Negative means opposite, this is why a low pH has MORE H+ ions
84. 84. [x] means concentration
85. 85. Acidic solutions have pH values less than 7
86. 86. More H+ ions
87. 87. Basic solutions have pH values greater than 7
88. 88. More OH- ions, less H+ ions
89. 89. Most biological fluids have pH values in the range of 6 to 8</li></li></ul><li>
90. 90. LE 3-8<br />pH Scale<br />0<br />1<br />Battery acid<br />2<br />Digestive (stomach)<br />juice, lemon juice<br />Vinegar, beer, wine,<br />cola<br />3<br />Increasingly Acidic<br />[H+] > [OH–]<br />4<br />Tomato juice<br />Black coffee<br />5<br />Rainwater<br />Urine<br />6<br />Neutral<br />[H+] = [OH–]<br />Pure water<br />7<br />Human blood<br />8<br />Seawater<br />9<br />10<br />Increasingly Basic<br />[H+] < [OH–]<br />Milk of magnesia<br />11<br />Household ammonia<br />12<br />Household bleach<br />13<br />Oven cleaner<br />14<br />
91. 91. Buffers<br />The internal pH of most living cells must remain close to pH 7<br />Buffers are substances that minimize changes in concentrations of H+ and OH- in a solution<br />Weak acids are a buffer for strong bases<br />Weak bases are a buffer for strong acids<br />Most buffers consist of an acid-base pair that reversibly combines with H+<br />
92. 92. Acids and Bases in the Living Things<br />Changes in concentrations of H+ and OH- can drastically affect the chemistry of a cell<br />When you breath…<br />CO2 + H2O ⇌ H+ + HCO-3<br />Carbon dioixde water hydrogen ion bicarbonate ion<br />
93. 93. The Threat of Acid Precipitation<br /><ul><li>Acid precipitation refers to rain, snow, or fog with a pH lower than 5.6
94. 94. Acid precipitation is caused mainly by the mixing of different pollutants with water in the air
95. 95. Acid precipitation can damage life in lakes and streams
96. 96. Effects of acid precipitation on soil chemistry are contributing to the decline of some forests</li></li></ul><li>LE 3-9<br />0<br />More<br />acidic<br />1<br />2<br />Acid<br />rain<br />3<br />4<br />5<br />Normal<br />rain<br />6<br />7<br />8<br />9<br />10<br />11<br />12<br />13<br />More<br />basic<br />14<br />
97. 97. Hydrophilic and Hydrophobic Substances<br />A hydrophilic substance is one that has an affinity (likes!) for water<br />A hydrophobic substance is one that does not have an affinity (does NOT like; scared of) for water<br />
98. 98. Law of Conservation of Energy and Matter<br />Energy and Matter cannot be created or destroyed, only change form<br />All atoms on one side of the equation must be accounted for on the other side of the equation<br />
99. 99. All chemical formulas MUST balance.   <br />C6H12O6 + O2------> CO2 + H2O<br /> Count atoms of each element on each side.<br />Is it balanced (does it follow law of conservation of matter?)<br />Increase number of molecules of each compound to balance.<br />Change COEFFICENT<br />Coefficient is the number before the compound (only number you can change)<br />C6H12O6 + 6O2------> 6CO2 + 6H2O<br />(glucose)     + (oxygen)-------(carbon dioxide)  + (water) <br />6 carbons on the left 6 carbons on the right<br />12 hydrogen on the left 12 hydrogen on the right<br />18 oxygen on the left 18 oxygen on the right<br /> <br />