1. Properties of Water *Hydrogen Bonding *Capillary Action *pH

2. Water Molecule Basic Structure http://programs.northlandcollege.edu/biology/Biology1111/animations/hydrogenbonds.html View this animation

4. Surface Tension The attraction between water molecules forms a “skin” on the surface of a water droplet. This is why water droplets are curved or dome-shaped.

5. Hydrogen Bonding Between Water Molecules Note that the bond between the Hydrogen and Oxygen atoms is a physical, covalent bond and is very strong. The hydrogen bond is a weak attraction between the slightly charged oxygen and hydrogen atoms and is not a physical bond.

6. Surface tension is essential for the survival of many plants and animals that live and hunt at the water’s surface in lakes, streams and rivers. Picture above is a water strider, a common freshwater insect. These insects are predators and eat many insect larvae including mosquitos. Surface tension is essential for the survival of many plants and animals that live and hunt at the water’s surface in lakes, streams and rivers. Picture above is a water strider, a common freshwater insect. These insects are predators and eat many insect larvae including mosquitos.

7. Detergents/Soaps are surfactants, or substances that break up the hydrogen bonds between water molecules so that the water molecules can spread out.

9. Adhesion and Cohesion Cohesion: “co” means “like” or similar.; attraction between two of the same substances; example is attraction between two water molecules. Adhesion: attraction between two different substances: example is attraction of water molecule to glass, or the inside of a xylem tube in a plant.

10. Adhesion, Cohesion and Capillary Action

11. Step 2: Capillary action Cohesion: polar water molecules tend to stick together with hydrogen bonds. Adhesion: water molecules tend to stick to polar surfaces.

12. Glass tube or xylem

13. Capillary action Cohesion and adhesion cause water to “crawl” up narrow tubes. The narrower the tube the higher the same mass of water can climb. Maximum height: 32 feet.

14. Transpiration: water movement in plants soil to root to leaf to atmosphere http://croptechnology.unl.edu/anim ationOut.cgi?anim_name=transpirat ion.swf&width=0&height=0 Click to view animation!

16. Bottom of leaf: stomates (stomata) are tiny pores in the bottom of a leaf that allows water and gas exchange with the environment.

17. Water and pH -pH stands for potential Hydrogen (H+) ions. The more H+ ions, the more acidic. -pH is based on water or how a substance reacts with water when dissolved in water. Dissociation means to split apart. The OH- or hydroxyl ions are considered alkaline or basic with H+ or hydrogen ions are considered acidic.

18. (Increasing alkalinity) Acids have more H+ ions; Bases (also called alkali) have higher OH- ion concentration.

19. Li + H 2 O ------------------  LiOH + H 2 gas Does lithium (Li) form an acid or base in water? Answer)…BASE (note the OH- group) Does lithium (Li) form an acid or base in water? Answer)…BASE (note the OH- group)

20. If it weren’t for the hydrogen bonding between water molecules… Life as we know it would NOT EXIST on this planet… Here are a few examples:

22. Water as a solvent and as a regulator of temperature in your body and the entire planet: http://programs.northlandcollege.edu/biology/Biology1111/animations/dissolve.html - View water as a great solvent (DISSOLVER!!) http://www.sumanasinc.com/webcontent/animations/content/propertiesofwater/water.html -View water’s properties and heat regulation -http://www.youtube.com/watch?v=BpQ5_uyUmfY&p=8098E1F65E432A4A&playnext=1&index=29 specific heat capacity