E-Binder‎ > ‎02 Chemistry of Life‎ > ‎Outlines‎ > ‎

Water Outline

      I.            Water

a.     Water is a polar covalent molecule

                                                             i.      Electronegativity and asymmetry give water molecules different charges on each side

                                                           ii.      Hydrogen bonding connects water molecules into a higher order of structural organization

                                                        iii.      Each water molecule can form a maximum of four hydrogen bonds with its neighboring water molecules

                                                        iv.      Causes emergent properties as a substance:

1.     Cohesive behavior

a.     Neighboring water molecules have structure

b.     Water droplets hold together due to this property

c.      For living things, drawing on water makes it move as if it were a chain of molecules

2.     Adhesion

a.     Water is attracted to similar substances and repelled by unlike substances

                                                                                                                                     i.      Attracts other polar molecules (hydrophilic)

                                                                                                                                   ii.      Repels or will not mix with nonpolar substances (hydrophobic)

b.     Helps with waterproofing of cell membranes

3.     Resists temperature change

a.     Water has a high specific heat or the amount of energy needed to change the temperature of a substance

                                                                                                                                     i.      Water = 1 cal/g/°C 

                                                                                                                                   ii.      Aluminum = 0.04 cal/g/°C 

b.     A large body of water can absorb heat releasing it during cooler seasons reducing shock to aquatic life

4.     High heat of vaporization

a.     Vaporization is going from a liquid to a gas

b.     When water evaporates, it transfers a lot of energy

c.      Evaporative cooling lowers the temperature of surfaces

5.     Expands when freezing

a.     Water becomes less dense as it cools

b.     As a solid, it floats allowing life to life below the ice surface

6.     Universal solvent

a.     Water makes solutions which is a homogenous mixture

b.     Water-solubility

b.     pH

                                                             i.      water can  be broken down into H+ hydrogen ion (or a donated proton) and OH- (hydroxide ion)

                                                           ii.      Acids and Bases

1.     higher H+ is a lower pH and is an acid

2.     higher OH- is a higher pH and is a base