1 PROPERTIES OF WATER Water is everywhere. It is in the air we breathe. It is in every cell in your body. Water is an unusual substance with special properties.

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PROPERTIES OF WATERPROPERTIES OF WATER Water is everywhere. It is in the air we breathe.

It is in every cell in your body. Water is an unusual substance with special properties.

1. Why does water “bead up” (stick together)2. Why does Ice float?3. How does water rise from the roots of a

redwood tree to the very top? 4. Why is water called the universal solvent?5. Why don’t oil and water mix?

Water is everywhere. It is in the air we breathe. It is in every cell in your body. Water is an unusual substance with special properties.

1. Why does water “bead up” (stick together)2. Why does Ice float?3. How does water rise from the roots of a

redwood tree to the very top? 4. Why is water called the universal solvent?5. Why don’t oil and water mix?

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HYDROGEN BONDINGHYDROGEN BONDINGDEFINE: Electronegativity Hydrogen bond nonpolar Polar covalent bond Cohesion Surface tension Heat Temperature Density

DEFINE: Electronegativity Hydrogen bond nonpolar Polar covalent bond Cohesion Surface tension Heat Temperature Density

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Hydrogen Bonding

Electronegativity- an atoms attraction for the shared electrons (covalent bond = sharing)

Ice Liquid

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Hydrogen Bonding

H 2 O = Polar Covalent Bond

H-bonds: Weak & easily broken

Oxygen - slightly (-)

Hydrogen slightly (+)

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POLARITYPOLARITY NONPOLAR - EQUAL SHARING OF

ELECTRONS (H2) , (O2) , (CH4) Non-polar compounds are hydrophobic (water fearing) and not

easily dissolved in water.

POLAR - UNEQUAL SHARING OF ELECTRONS ( H 2 O)

Hydrophylic (water loving) - the polarity of water allows it to dissolve other polar molecules. LIKE DISSOLVES LIKE

NONPOLAR - EQUAL SHARING OF ELECTRONS (H2) , (O2) , (CH4)

Non-polar compounds are hydrophobic (water fearing) and not easily dissolved in water.

POLAR - UNEQUAL SHARING OF ELECTRONS ( H 2 O)

Hydrophylic (water loving) - the polarity of water allows it to dissolve other polar molecules. LIKE DISSOLVES LIKE

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Water-soluble protein

Hydrophilic - like water

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HYDROPHOBIC - OIL & WATER DON’T MIX!!Aerial images of the Deepwater Horizon oil spill taken from a US Coast Guard aircraft.

HYDROPHOBIC - OIL & WATER DON’T MIX!!Aerial images of the Deepwater Horizon oil spill taken from a US Coast Guard aircraft.

April 20, 2010 - Explosion and fire on drilling rig The Gulf of Mexico

April 20, 2010 - Explosion and fire on drilling rig The Gulf of Mexico

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“Dissociation” of water

Making ions (charged particles)

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Surface tension

Difficult to stretch or break the surface of a liquid

Cohesion - like substances sticking together

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Ice, water, vapor - phases of water

Heat - amount of energy associated with the movement of the atoms & molecules in a body of matterTemperature - measure of the intensity of heat; the average speed of moleculesWater resists temperature changes by absorbing a lot of heat.

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Density of WaterDensity = mass/volume

Density of WaterDensity = mass/volume

The reason ice floats is because a certain mass of ice occupies more space than the same mass of liquid water. Ice is one of the only substances that expands when it freezes

The reason ice floats is because a certain mass of ice occupies more space than the same mass of liquid water. Ice is one of the only substances that expands when it freezes

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pHpH = – log [H+]

Log scale means 10X change per unit!

[H+]= 10-1M

[H+]= 10-9 M

Adding or removing hydrogen ions changes the pH of a solution.

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BuffersBuffers resist changes to the pH of a solution when H+ or OH- is added to the solution.

•Buffers accept hydrogen ions from the solution when they are in excess and donate hydrogen ions when they have been depleted.