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States of Matter & Bond States of Matter & Bond Strength Strength Gas Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. Liquid Liquid = Molecules loosely bonded to one another; bonds easily broken, so liquids flow. Volume is fixed, but takes shape of container. Solid Solid = Molecules strongly bonded to one another; fixed size and shape. Bend or break with applied force.
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States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

Dec 28, 2015

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Phillip Austin
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Page 1: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

States of Matter & Bond StrengthStates of Matter & Bond Strength

– GasGas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container.

– LiquidLiquid = Molecules loosely bonded to one another; bonds easily broken, so liquids flow. Volume is fixed, but takes shape of container.

– SolidSolid = Molecules strongly bonded to one another; fixed size and shape. Bend or break with applied force.

Page 2: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

The Water MoleculeThe Water Molecule

º

If water weren’t polar, it would freeze at -90ºC (-130ºF) and boil at -68ºC (-90ºF).

And it wouldn’t be nearly so good a solvent (dissolver of salts etc).

Page 3: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

The Water MoleculeThe Water Molecule

(ice in glaciers & polar ice

caps)

(oceans, rivers, & lakes)

(water vapor in the

atmosphere)

Strongly bonded Loosely bonded Not bonded

Melting Evaporation

Condensation Freezing

Page 4: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

The Water Molecule - Types of BondsThe Water Molecule - Types of Bonds

• Covalent bondsCovalent bonds– Within each H2O molecule– Bonds the H’s to the O– Very strong! (sharing electrons)

• Hydrogen bondsHydrogen bonds– Between H2O molecules– Bonds H2O molecules to each other– Constantly forming and breaking in

liquid water

Page 5: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

The Water Molecule - Types of BondsThe Water Molecule - Types of Bonds

• High surface tensionHigh surface tension– Hydrogen bonding creates “skin”

– Important for living organisms• Capillarity (e.g., in vascular plants)

Cohesion

Page 6: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

The Water Molecule - Types of BondsThe Water Molecule - Types of Bonds

• Universal solventUniversal solvent– Electrostatic bonds between dipolar

water and ions• Ocean is salty ( NaCl Na+ + Cl– )

Adhesion

Page 7: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

B. B. Density & TemperatureDensity & Temperature

• Density ( Density ( ) ) = Mass / Volume = Mass / Volume (in g/cm3)

• Ratio, so if mass mass or if volume volume • Relative water density affects water-

current development

• Water-density vs. organism-density determines whether an organism will sink or float

– Some floating organisms can vary their density!

Page 8: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

Density & TemperatureDensity & Temperature• Density ( Density ( ) ) = Mass / Volume = Mass / Volume (in g/cm3)

• Most substances get denser (that is, have more mass per unit volume) as they get colder ( T T )

• This is only true for water down to ~4ºC (remember, water freezes at 0ºC)

• As water cools from ~4ºC to 0ºC, it becomes less dense! ( T T )

• The maximum density of fresh water ( maxmax ) is at 3.98ºC

• Let’s draw all that on a graphLet’s draw all that on a graph

Page 9: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

Temperature

D

ensi

ty

Density & TemperatureDensity & Temperature

““Normal” substanceNormal” substance

Page 10: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

Density & TemperatureDensity & Temperature

Temperature

D

ensi

ty

WaterWater

4ºC

Page 11: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

Density & TemperatureDensity & Temperature

(Fig. 6-3, p.102)

Page 12: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

Density & TemperatureDensity & Temperature

As T toward 4ºC:Amount of thermal motion Molecules occupy less volume (same mass) Density

As T from 4ºC to 0ºC:Molecules begin to line up to form ice crystals = Open, 6-sided structures Molecules occupy more volume (same mass) Density

Page 13: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

C. C. Heat & TemperatureHeat & Temperature• HeatHeat

– = Energy produced by the random vibration of atoms or molecules

– A measure of how many molecules are vibrating and how rapidly they’re vibrating

• TemperatureTemperature– = An object’s response to an input or

removal of heat– Records only how rapidly the molecules are

vibrating

• Heat Capacity Heat Capacity = a link= a link– = The amount of heat required to raise the

temperature of 1 gram of a substance by 1ºC

Page 14: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

Heat & TemperatureHeat & Temperature

º

(p.102)

1 calorie Amount of heat required to raise 1

gram of pure liquid water by 1ºC

VERY HIGH!

Water resists changing

temperature when it absorbs or releases heat

Page 15: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.

D. D. Changes of StateChanges of State

Let’s draw all that on a graphLet’s draw all that on a graph (Fig. 6-6, p.104)

Page 16: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.
Page 17: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.
Page 18: States of Matter & Bond Strength –Gas –Gas = Molecules not bonded to one another; move independently. Takes the volume and shape of its container. –Liquid.