- Water is essential for life and has many important properties due to its polarity and ability to form hydrogen bonds. It acts as a solvent, coolant, and transport medium within organisms. - The polarity and hydrogen bonding of water molecules gives water high heat capacity, specific boiling and freezing points, and allows it to dissolve many substances. Hydrogen bonding also contributes to water's cohesive and adhesive properties. - Water's properties help sustain life and allow organisms to regulate temperature and transport nutrients and wastes. However, acid rain can lower the pH of bodies of water and damage ecosystems.

1. Chemical Elements and Water

5. Examples of Chemical Elements and Their Roles Used in neurons (nerve cells) for the transmission of nerve impulses Sodium Needed to make hemoglobin and thus to carry oxygen in blood Iron Part of the phosphate groups in ATP and DNA molecules Phosphorus Needed to make the mineral that strengthens bones and teeth Calcium Part of the amine groups of amino acids and therefore proteins Nitrogen Role in Plants or Animals Element

8. Water molecules form Hydrogen bonds slightly positive charge slightly negative charge hydrogen bond between (+) and (-) areas of different water molecules

18. Like dissolves like: water can interact with other polar molecules

21. pH, Acids, Bases, Buffers

29. Figure 3.10x1 Pulp mill

30. Figure 3.10x2 Acid rain damage to statuary, 1908 & 1968