The Extraordinary Properties of Water. WATER is important for all living things Average person ~~...

The Extraordinary The Extraordinary Properties of Properties of WaterWater

WATER is important for all living thingsAverage person ~~ 60-70%

waterHuman brain ~~ 90%

Cells are about 70-95% water

WaterWater

•A water molecule (H2O), is made up of three atoms: one oxygen and two hydrogen.

O

Polar MoleculesBecause of the location ofelectrons in molecules, some molecules have an_________ pattern of____________________

More ___ on one side; More ___ on the other

EX: water

UNEVEN

+-

ELECTRIC CHARGE

WHAT HOLDS MOLECULES TOGETHER?

Molecules are _____________by the________ between ______________regions of nearby molecules

= _____________________VAN DER WAALS FORCES

HELD TOGETHER

ATTRACTION OPPOSITELY CHARGED

Bonds that form between the_________ charged _____________in one molecule and a __________ charged _________in a nearby molecule are called_____________________

POSITIVELY

HYDROGEN BONDS

HYDROGEN ATOM

NEGATIVELY ATOM

HYDROGEN BONDS

EX: water molecules are held together by Hydrogen bonds

Hydrogen BondsHydrogen Bondsone hydrogen bond is weak , but one hydrogen bond is weak , but

many hydrogen bonds are strongmany hydrogen bonds are strong

http://www.northland.cc.mn.us/biology/biology1111/animations/hydrogenbonds.html

CLICK LINK BELOW FOR AN ANIMATION FOR BONDING

Hydrogen bonds

•weak

•form, break, and reform with great frequency

•Each bond only lasts a few trillionths of a second

However, hydrogen bonding is what gives water it’s essential properties…

Each water molecule can form hydrogen bonds with up to four neighbors

WaterWater

•At sea level, pure water boils at At sea level, pure water boils at 100 °C and freezes at 0 °C.100 °C and freezes at 0 °C.

•The boiling temperature of The boiling temperature of water decreases at higher water decreases at higher elevations (lower atmospheric elevations (lower atmospheric pressure). pressure).

•For this reason, an egg will For this reason, an egg will take longer to boil at higher take longer to boil at higher altitudesaltitudes.

Properties of WaterProperties of Water

•What are they?What are they?

Properties of WaterProperties of Water

•CohesionCohesion

Properties of WaterProperties of Water

•CohesionCohesion

•AdhesionAdhesion

This is a great notes interaction! It will help you remember and not get them confused!

Properties of WaterProperties of Water

•CohesionCohesion•AdhesionAdhesion•High Specific HeatHigh Specific Heat

Properties of WaterProperties of Water

•CohesionCohesion•AdhesionAdhesion•High Specific HeatHigh Specific Heat•High Heat of High Heat of VaporizationVaporization

Properties of WaterProperties of Water

•CohesionCohesion•AdhesionAdhesion•High Specific HeatHigh Specific Heat•High Heat of High Heat of VaporizationVaporization

•Less Dense as a SolidLess Dense as a Solid

CohesionCohesion Attraction between particles Attraction between particles of of the same substance the same substance

- why water is attracted to why water is attracted to itselfitself Results in:Results in:Surface tensionSurface tension (a measure of (a measure of the strength of water’s surface) the strength of water’s surface)

•surface film on water surface film on water -allows insects to walk on the -allows insects to walk on the

surface of water surface of water

18

Water Properties

•Polarity

CohesivenessAdhesivene

ss

Surface Tension

• http://www.visionlearning.com/library/module_viewer.php?mid=57

• http://www.youtube.com/watch?v=Qhsxo7vY8ac

Basilisk lizard: The Jesus Lizard

AdhesionAdhesion•Attraction between two different Attraction between two different substances. substances.

- water will make hydrogen - water will make hydrogen bonds with other surfaces such as bonds with other surfaces such as glass, soil, plant tissues, and cotton. glass, soil, plant tissues, and cotton.

.

Copyright Pearson Prentice Hall

•CapillaryCapillary actionaction-water molecules will “tow” each other -water molecules will “tow” each other along when in a thin glass tube. along when in a thin glass tube.

- i.e. transpiration process which plants and trees - i.e. transpiration process which plants and trees remove water from the soil, and paper towels soak up remove water from the soil, and paper towels soak up water.water.

High Specific HeatHigh Specific Heat

Amount of heat needed to raise Amount of heat needed to raise or lower 1g of a substance 1° C.or lower 1g of a substance 1° C.

•Water Water resistsresists temperature temperature change, both for heating and change, both for heating and cooling.cooling.

•Water can absorb or release Water can absorb or release large amounts of heat energy large amounts of heat energy with little change in actual with little change in actual temperature.temperature.

High Heat of High Heat of VaporizationVaporization

Amount of energy to convert Amount of energy to convert 1g or a substance from a liquid 1g or a substance from a liquid to a gasto a gas

• In order for water to In order for water to evaporate, hydrogen bonds evaporate, hydrogen bonds must be broken. As water must be broken. As water evaporates, it removes a lot of evaporates, it removes a lot of heat with it.heat with it.

Water has a high heat capacity

Heat capacity (specific heat) is the quantity of heat required to change the temperature of a substance by 1 degree

Water can store a lot of heat!It changes temperature very slowly

• “Water vapor forms a kind of global ‘blanket’ which helps to keep the earth warm. Heat radiated from the sun-warmed surface of the earth is

absorbed and held by the vapor.”

Water is Less Dense as Water is Less Dense as a Solida Solid

•Ice is less dense as a solid than as a liquid (ice floats)Liquid water has hydrogen bonds that are constantly being broken and reformed.Frozen water forms a crystal-like lattice whereby molecules are set at fixed distances.

Water is Less Dense as Water is Less Dense as a Solida Solid

•Which is ice and which is Which is ice and which is

water?water?

Water is Less Dense as a Water is Less Dense as a SolidSolid

WaterWater IceIce

HomeostasisHomeostasis• Ability to maintain a steady state Ability to maintain a steady state

despite changing conditionsdespite changing conditions• Water is important to this process Water is important to this process

because:because:a. Makes a a. Makes a good insulatorgood insulatorb. Resists temperature changeb. Resists temperature changec. c. Universal solventUniversal solventd. Coolantd. Coolante. Ice protects against e. Ice protects against temperature extremestemperature extremes

WATER IS THE UNIVERSAL SOLVENT

• http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/thermochem/solutionSalt.html

Cells are about 70-95% water90% of cytoplasm is water92% of blood plasma is water97% of tissue fluid and lymph is water

IMPORTANCE OF WATER FOR ORGANISMS

Takes part in metabolic reactions:

• photosynthesis: water is a raw material in the light stage

• Respiration: aerobic respiration produces water

• Anabolism: produced when macromolecules are made

• Catabolism: water is used to break the bonds in macromolecules

REMEMBER: METABOLISM = ANABOLISM + CATABOLISM

Movement of materials through cell membranes:

• Diffusion• Osmosis• Active transport

Turgor pressure plays an important role in the support of plants

Loss of turgor pressure:

Plant wilts

turgor pressure restored

Plant supported