1. 1 The Chemistry… …of WATER?

2. 2 Water is a CHEMICAL? Water is one of our most abundant chemicals Chemical Formula is H 2 O most recognized of all the chemical formulas H O H YES!

3. 3 What formula tell us? H2OH2O The formula H 2 0 tells us that one molecule of water is made of 2 atoms of hydrogen and 1 atom of oxygen bonded together. The bonds which hold the hydrogen and oxygen together are called covalent bonds. They share electrons.

4. 4 Water is a polar molecule. + I  one side of a water molecule is slightly positive and the other is slightly negative.  forms a “V” shape of oxygen atom with 2 hydrogen atoms  hydrogen bonds are weak and water constantly reforms  when water freezes it forms a lattice, with air spaces… Remember it floats.

5. 5 Polar Molecule The charged ends of a polar solvent can separate the charged ends of a polar solute. As a general rule: Like Dissolves Like + - Think about it… Water and vinegar mix, however oil and water do not mix. Is vinegar polar or non-polar? Is oil polar or non-polar? POLARNON-POLAR

6. 6 Everything! Because water has a slightly negative end and a slightly positive end or pole, it can interact with itself. WOW! The slightly positive hydrogen end of one molecule can interact with the slightly negative end of another water molecule. This interaction is called "Hydrogen Bonding,” and it explains why water forms “drops” when other liquids do not. What does polarization have to do with the properties of water?

7. 7 Network of Water Molecules Because every water molecule can form four Hydrogen Bonds, an elaborate network of molecules is formed….the Lattice!

8. 8 Water – the Common Solvent Water is the most common substance on earth. It makes up 70% of the earth’s surface. 65% of your body mass is composed of water. Fresh Water Most important liquid on Earth – 1% freshwater, – 97% ocean, – 2% frozen polar caps

9. 9 What is in your tap water? Acids - dissolved CO 2 from soils, corrodes pipes, leaches out Pb and Cu Bases - Ca and Mg-hard water Chlorine - changes taste, smells, kills bacteria Fluorine - prevents tooth decay Iron - causes orange stains Copper - changes taste, causes blue stains, needed for health Lead - toxic even in low concentrations Other chemicals in surface water Phosphorus - from detergents and fertilizers Nitrogen - from decayed organic matter

10. Carbonated water contains CO 2, make it bubbly Types of Bottled Water Potable water bottled from city or town source may contain minerals and additives Distilled water most minerals removed deionization or reverse osmosis Mineral water must contain 250 mg/L of dissolved minerals, such as Ca, K, Mg minerals must be natural, not added must be collected from underground source

11. 11 The Water Cycle Also named Hydrologic Cycle driven by the SUN Starts with groundwater water seeps through soil and rocks, filtering out microorganisms becomes slightly acidic from CO 2 arrives in an aquifer (underground storage area) Ends by flowing into the ocean

12. 12 The Water Cycle – Evaporates from the oceans, rivers, lakes and streams – Transpiration -plants lose water to atmosphere – Falls back to Earth, through Precipitation – surface runoff collects water in lakes, rivers and streams where it once again becomes ground water.