??Water =LifeWater =Life

Why water is so FREAKIN Why water is so FREAKIN cool:cool:

1. It’s Polarity gives potential.1. It’s Polarity gives potential. 2. Cohesion/Adhesion/Surface 2. Cohesion/Adhesion/Surface

TensionTension 3. Amazing solvent3. Amazing solvent 4. Specific Heat4. Specific Heat

WaterWaterThe most important property of The most important property of

the water molecule is that it is the water molecule is that it is slightly charged on each end slightly charged on each end due to an uneven distribution of due to an uneven distribution of ee--ss +

+

-

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

WaterWater AdhesionAdhesion – water molecules – water molecules

attracted to other slightly attracted to other slightly charged moleculescharged molecules

CapillarityCapillarity – combination of the – combination of the other two forces which causes other two forces which causes the movement of water upward the movement of water upward through tube cells (xylem)through tube cells (xylem)

Transpiration pullTranspiration pull

Impact on Impact on Life???Life???

Terms:Terms:

Kinetic Energy (KE) = Energy of motionKinetic Energy (KE) = Energy of motion

Heat = TOTAL amount of KEHeat = TOTAL amount of KE

Temperature = Intensity of Temperature = Intensity of heat/averageheat/average

Measured in Kcal, cal, joule, etc…Measured in Kcal, cal, joule, etc…

Specific HeatSpecific Heat

Amount of Amount of heat needed heat needed to raise 1 to raise 1 gram of ‘stuff’ gram of ‘stuff’ 1 degree 1 degree Celsius. Celsius.

Or…Or…

How well How well ‘stuff’ resists ‘stuff’ resists changing changing temperaturestemperatures. (Water is . (Water is stubborn)stubborn)

Specific Heat = Life???Specific Heat = Life???

Heat of Vaporization = Heat of Vaporization = Life???Life???

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

A solution is a substance that A solution is a substance that is is uniformly spread throughoutuniformly spread throughout; ; (Homogeneous)(Homogeneous)

Solvent – substance that does the Solvent – substance that does the dissolvingdissolving

Solute – what is to be dissolvedSolute – what is to be dissolved

Examples:Examples: Sugar and waterSugar and water Tea, coffee (Life?????????)Tea, coffee (Life?????????)

Hydrophobic or hydrophilicHydrophobic or hydrophilic

Properties of WaterProperties of WaterPropertyProperty Example of Importance Example of Importance to Life to Life

CohesionCohesion Water flows, forming Water flows, forming habitats and a matrix for habitats and a matrix for biological moleculesbiological molecules

High (specific) heat High (specific) heat capacity (1g, 1capacity (1g, 1OOC)C)

Water regulates constant Water regulates constant internal body temperatureinternal body temperature

High heat of vaporization High heat of vaporization (1g to gas)(1g to gas)

Evaporation (evaporative Evaporation (evaporative cooling – sweating)cooling – sweating)

AdhesionAdhesion Water acts as a solventWater acts as a solvent

Solid less dense than Solid less dense than liquidliquid

Keeps ponds and lakes Keeps ponds and lakes liquidliquid

The The more more

HH++ present, present,

the the lower lower the pH the pH

##

The more OH-

present the

higher the pH #

WaterWater Acids – Compounds that release HAcids – Compounds that release H++

ions (much like how NaCl dissociates ions (much like how NaCl dissociates in water but Hin water but H++ are one of the most are one of the most reactive ions on the planet)reactive ions on the planet)

Bases – Compounds that release OHBases – Compounds that release OH-- (is the opposite of an acid; the OH(is the opposite of an acid; the OH-- are as reactive as Hare as reactive as H++))

Combining an acid and a base Combining an acid and a base produces water and a saltproduces water and a salt

Dissociation of WaterDissociation of Water Water can dissociate into the Water can dissociate into the

hydrogen and hydroxide ionshydrogen and hydroxide ions HH22O O H H++ + OH + OH- (LIFE???????)- (LIFE???????)