Bell ringer

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Bell ringer

• Time Warp water droplets

• Time Warp water droplets

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KEY CONCEPTWaters unique properties allow life
to exist on Earth.
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(No Transcript)
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FL NGSSS

• SC.912.L.18.12 Discuss the special properties of
  water that contribute to Earths suitability as
  an environment for life cohesive behavior,
  ability to moderate temperature, expansion upon
  freezing, and versatility as a solvent. (
  Moderate)

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THE PROPERTIES OF WATER Water has some very
unique properties that make this molecule unlike
ANY other. And we are made up of about 70 water!
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Your body is made up of mostly of water.
Approximately 85 of your brain, 80 of your
blood and 70 of your muscle is water. Every cell
in your body needs water to live.
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Life depends on hydrogen bonds in water.

• Water is a polar molecule.
• Polar molecules have slightly
• charged regions.

• Nonpolar molecules do not have charged regions.
• Hydrogen bonds is a weak bond form between
• slightly positive hydrogen atoms and slightly
  negative
• atoms.

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• Hydrogen bonds are responsible for three
  important properties of water.

large amount of energy needed to produce an
increase in temperature

• High specific heat-
• Cohesion - water molecules
• stick to each other
• Adhesion - water molecules
• stick to other substances

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Cohesion

• Waters tendency to cling together
• Water in space

When the negative end of a water molecule
attracts the positive end of another water
molecule, and the molecules stick together, this
is called cohesion.
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Adhesion

• Adhesion, or capillary action, is when water
  molecules are attracted to other substances with
  a negative or positive charges. This is why water
  "climbs" up a piece of paper or a straw above the
  surface level of the water.        
• This figure shows water adhesion

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Because of the cohesive properties of water,
trees such as the giant sequoia are able to
transport water molecules from the soil to their
leaves 300 ft. above.
WATER STRONG COHESIVENESS
300 ft.
Water molecule released into the atmosphere
As each water molecule evaporates, it pulls
additional water up through the tree because of
the sticky-ness of the hydrogen bonds that link
the water molecules.
Water molecules pulled upward
6-ft.-tall man
Water molecule pulled into root system
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Phloem and Xylem
-Phloem-Transport sugars and molecules created by
the plant. Transports food made during
photosynthesis.Xylem-System of tubes in a plant
that transport water and dissolved minerals. The
xylem distributes the water throughout the plant.
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Trouble on the Surface Lab
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WATER HIGH SURFACE TENSION
Pressure applied to water surface
Hydrogen bond
V-shaped water molecules are held together by
hydrogen bonds. The bonds are just strong enough
to give water a surface tension with net-like
properties.

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Surface Tension

• The cohesive forces between liquid molecules
• are responsible for the phenomenon known as
• surface tension.
• The molecules at the surface do not have other
  like molecules on all sides of them and
  consequently they cohere more strongly to those
  directly
• associated with them on the surface.
• This forms a surface "film" which makes
• it more difficult to move an object
• through the surface than to move it
• when it is completely submersed.

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Other unique properties of water

• Only substance to that exists free in nature in
  all three states (solid, liquid, and gas)
• High boiling point
• Low freezing point
• Viscosity increases as its temperature is lowered
• A strong surface tension
• A relatively high density to support animals with
  no or delicate skeletal systems
• A high heat capacity which maintains relativity
  stable and slow changing internal temperature
• Ability to dissolve most substances

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Universal Solvent

• Since unlike charges attract, the negative end
  of water will be attracted to the positive sodium
  ion. The positive end of water will be attracted
  to the negative chloride ion.Since water is
  always in motion, it will pull on the ionic
  compound and move the ions away from each other.
  This dissolves the ionic compound.

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Many compounds dissolve in water.

• A solution is formed when one substance dissolves
  in another.
• A solution is a homogeneous
• mixture.
• Solvents dissolve other
• substances.
• Solutes dissolve in a solvent.

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• Like dissolves like.

• Polar solvents dissolve polar solutes.
• Nonpolar solvents dissolve nonpolar solutes.
• Polar substances and
• nonpolar substances generally remain separate.

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Common Misconceptions

• Students often thinks that all solutes are solids
  and all solvent as are liquids.
• Correcting the misconception
• Solutions can involve different states of matter

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Some compounds form acids or bases.

• An acid releases a hydrogen ion when it dissolves
  in water.
• high H concentration
• pH less than 7

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• A base removes hydrogen ions from a solution.

• low H concentration
• pH greater than 7

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• A neutral solution has a pH of 7.

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pH Scale