? Water =Life

Why water is so FREAKIN cool: 1. It’s Polarity gives potential. 2. Cohesion/Adhesion/Surface Tension 3. Amazing solvent 4. Specific Heat

Water The most important property of the water molecule is that it is slightly charged on each end due to an uneven distribution of e-s + -

Cohesion – force attracting water molecules to each other. Causes surface tension, which is why this lizard can “run” on water

Water Adhesion – water molecules attracted to other slightly charged molecules Capillarity – combination of the other two forces which causes the movement of water upward through tube cells (xylem) Transpiration pull

Impact on Life???

Terms: Kinetic Energy (KE) = Energy of motion Heat = TOTAL amount of KE Temperature = Intensity of heat/average Measured in Kcal, cal, joule, etc…

Amount of heat needed to raise 1 gram of ‘stuff’ 1 degree Celsius. Specific Heat Amount of heat needed to raise 1 gram of ‘stuff’ 1 degree Celsius. Or… How well ‘stuff’ resists changing temperatures. (Water is stubborn)

Specific Heat = Life???

Heat of Vaporization = Life???

Most substances are most dense in their solid (frozen) state than in their liquid state. Water is different because of hydrogen bonding. Ice floats because it is about 9% less dense than liquid water. In other words, ice takes up about 9% more space than water, so a liter of ice weighs less than a liter water. LIFE?????

A solution is a substance that is uniformly spread throughout; (Homogeneous) Solvent – substance that does the dissolving Solute – what is to be dissolved Examples: Sugar and water Tea, coffee (Life?????????)

Hydrophobic or hydrophilic

Example of Importance to Life Properties of Water Property Example of Importance to Life Cohesion Water flows, forming habitats and a matrix for biological molecules High (specific) heat capacity (1g, 1OC) Water regulates constant internal body temperature High heat of vaporization (1g to gas) Evaporation (evaporative cooling – sweating) Adhesion Water acts as a solvent Solid less dense than liquid Keeps ponds and lakes liquid

The more H+ present, the lower the pH # The more OH- present the higher the pH #

Water Acids – Compounds that release H+ ions (much like how NaCl dissociates in water but H+ are one of the most reactive ions on the planet) Bases – Compounds that release OH- (is the opposite of an acid; the OH- are as reactive as H+) Combining an acid and a base produces water and a salt

Dissociation of Water Water can dissociate into the hydrogen and hydroxide ions H2O  H+ + OH- (LIFE???????)