BSCI170 Lecture Notes - Covalent Bond, Hydrogen Bond, Surface Tension
Document Summary
Water is essential for life: life began in water, life evolved in water, living organisms . What is special about water: simple structure: h-o-h (h2o, each o-h covalent bond is polar. Water is only substance to exist in all three physical forms in the natural environment: solid (crystalline, liquid, gas (vapor) Moderation of temperature: water has a high specific heat, high heat of vaporization. Solid water is less dense than liquid water. Ice: hydrogen bonds are stable: liquid water: hydrogen bonds constantly break and reform, organisms can flourish. Water is an excellent solvent: excellent solvent for polar and charged molecules and compounds, hydrophilic, water loving , universal solvent, most biologically important molecules are hydrophilic, h2o forms a hydration shell around hydrophilic substances. [h+] = 10-7 m: h+ is a hydrogen ion = proton. [oh-] in pure water = 10-7 m: oh- is called hydroxide, both h3o+ (h+) and oh- are chemically highly reactive.
