Properties of Water The most unusual usual liquid.

Properties of WaterProperties of Water

The most unusual usual The most unusual usual liquidliquid

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

Two atoms of Two atoms of hydrogen and one hydrogen and one atom of oxygenatom of oxygen

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Water is a Polar MoleculeWater is a Polar Molecule

• A molecule that has a A molecule that has a slight electric chargeslight electric charge– Hydrogen has a Hydrogen has a

positive chargepositive charge– Oxygen has a negative Oxygen has a negative

charge.charge.

• The positive The positive hydrogen ends hydrogen ends attract the negative attract the negative oxygen ends of oxygen ends of another molecule.another molecule.

• Molecules stick Molecules stick together.together.

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SURFACE TENSIONSURFACE TENSION

• Many of water’s Many of water’s unusual properties are unusual properties are because water is a because water is a polar molecule.polar molecule.

• Surface TensionSurface Tension: The : The tightness across the tightness across the surface of water surface of water – Causes a curved surface Causes a curved surface

and round water dropsand round water drops– Created by water Created by water

molecules pulling against molecules pulling against each other.each other.

CAPILLARY ACTIONCAPILLARY ACTION

• Capillary Action: Capillary Action: The ability of water The ability of water to pass through to pass through materials with pores.materials with pores.– Polarity of molecules Polarity of molecules

cause water cause water molecules to stick to molecules to stick to the side of a material the side of a material and pulls up other and pulls up other molecules. molecules.

– Why towels oak up Why towels oak up water.water.

THE UNIVERSAL SOLVENTTHE UNIVERSAL SOLVENT

• Solvent:Solvent: Any Any substance that substance that dissolves another dissolves another substancesubstance

• Water is a good Water is a good solvent because it is solvent because it is a polar molecule.a polar molecule.– Attract other polar Attract other polar

molecules and pulls molecules and pulls them apart.them apart.

THE ONE AND ONLYTHE ONE AND ONLY

• Water is the only substance on earth that exists Water is the only substance on earth that exists naturally as a liquid, solid, and a gas. naturally as a liquid, solid, and a gas.

• Changing Changing statestate = changing the amount of energy in a = changing the amount of energy in a substance.substance.– More energy = more movement = faster and more spread out.More energy = more movement = faster and more spread out.

ICE

(SOLID)

WATER

(LIQUID)

VAPOR

(GAS)

Why does ice float?Why does ice float?

• When water freezes, When water freezes, the molecules attract the molecules attract in a in a matrix matrix that takes that takes up more space than up more space than the liquid form.the liquid form.

• This is very unusual. This is very unusual. Most substances are Most substances are more dense as a more dense as a solid.solid.

VOCABULARYVOCABULARY

Melting:Melting: When a solid changes into a liquid When a solid changes into a liquid

Freezing:Freezing: When a liquid changes into a When a liquid changes into a solid.solid.

Evaporation:Evaporation: When molecules at the When molecules at the surface of a liquid absorb enough energy surface of a liquid absorb enough energy from their surroundings to change into a from their surroundings to change into a gas.gas.

Condensation:Condensation: When a gas turns into a When a gas turns into a liquid.liquid.