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Properties of Water PolarPolar Surface TensionSurface Tension Cohesion/AdhesionCohesion/Adhesion Universal SolventUniversal Solvent Capillary ActionCapillary Action High Specific HeatHigh Specific Heat Less Dense as a SolidLess Dense as a Solid

Water threeA water molecule (H 2 O), is made up of three atoms --- one oxygen and two hydrogen. H H O

O H H 1 molecule of water is made up of 2 hydrogen atoms bonded with 1 oxygen atom STRUCTURE OF WATER

O H H 1 molecule of water

O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H O H H A LOT OF MOLECULES OF WATER

Millions of molecules of water make up 1 raindrop

Water is Polar oxygennegativeThe oxygen end “acts” negative hydrogenpositiveThe hydrogen end “acts” positive POLARCauses the water to be POLAR neutralZero Net ChargeHowever, Water is neutral --- Zero Net Charge

Interaction Between Water Molecules Negative Oxygen end of one water molecule is attracted to the Positive Hydrogen end of another water molecule to form a HYDROGEN BOND

O H H - + +

POLAR MOLECULE The positive hydrogen ends of 1 molecule are attracted to the negative end of the oxygen of another molecule. O H H O H H

POLAR MOLECULE A molecule that has electrically charged areas. Also called a polar substance or polar compound. _ + DURACELL

POLAR MOLECULE THE PROPERTIES OF: Cohesion, adhesion, specific heat, universal solvent, capillary action, surface tension ALL HAPPEN BECAUSE WATER IS A POLAR SUBSTANCE!

NON-POLAR SUBSTANCES Non-polar substances do not have charged ends Are hydrophobic and are not easily dissolved in water DURACELL

SURFACE TENSION The tightness across the surface of water that is caused by the polar molecules pulling on one another. Makes the surface act like a solid

SURFACE TENSION

COHESION Because water is a polar molecule, it is attracted to itself. CohesionCohesion – is the attractive force between water molecules. O H H O H H

Water molecules like to stick to each other. COHESION Rubbing alcohol doesn’t like to stick to itself as much as water.

Cohesion … Helps insects walk across water

ADHESION Because water is a polar molecule, it is attracted to other substances. AdhesionAdhesion – occurs when molecules of water are attracted to other substances.

WATER DROPLET WINDSHIELD Adhesion is going on between the windshield and the water droplet.

ADHESION

COHESION Water molecules like to stick to each other. ADHESION Water molecules like to stick to other things.

UNIVERSAL SOLVENT

This is a nickname given to water. Water dissolves LOTS of things. Remember: SOLVENT = the thing doing the dissolving SOLUTE = the thing that dissolves away Other polar molecules can be dissolved by water.

Universal Solvent Why is water so good at dissolving things? Because water is a polar molecule and is shaped like a wedge, it is able to break up substances into smaller pieces (dissolve).

CAPILLARY ACTION The combined force of attraction among water molecules and with the molecules of the surrounding material. Cohesion + Adhesion

CAPILLARY ACTION

Adhesion Causes Capillary Action Which gives water the ability to “climb” structures

SPECIFIC HEAT Specific Heat = the amount of energy needed to increase the temperature of something 1 degree C. Water has a really HIGH specific heat That means it takes a lot of energy for water to increase its temperature. This is because of the STRONG ATTRACTION between water molecules. It’s POLAR!

SPECIFIC HEAT BEACH = 200°F WATER = 75°F

Water is Less Dense as a Solid WaterIce

34 Ice, water, vapor Lower density of ice causes it to float & insulate the water below

Properties of Water At sea level, pure water boils at 100 °C and freezes at 0 °C.At sea level, pure water boils at 100 °C and freezes at 0 °C. The boiling temperature of water decreases at higher elevations (lower atmospheric pressure).The boiling temperature of water decreases at higher elevations (lower atmospheric pressure). For this reason, an egg will take longer to boil at higher altitudesFor this reason, an egg will take longer to boil at higher altitudes

STRUCTURE OF WATER POLAR MOLECULE CAPILLARY ACTION SURFACE TENSION UNIVERSAL SOLVENT COHESION ADHESION DENSITY BUOYANCY SPECIFIC HEAT