Properties of Water

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Properties of Water

• If there are other beings who have seen Earth, he
  said, they must surely call it the blue planet.
  The astronaut was referring to the blue
  appearance of the water in the oceans, which
  cover three fourths of Earths surface. Water is
  also the single most abundant compound in most
  living things.

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Thing to know

• Polarity- Electrons are not shared equally in a
  lot of molecules.
• When electrons (-) are pulled more to one side of
  a molecule that side has a negative charge
• The other side has a positive charge.
• Big atoms tend to hog electrons

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Things to know

• Hydrogen bond Because of positive and negative
  charges of water (polarity).
• Water attracts other water molecules.
• Cohesion- attraction between molecules of the
  same substance.
• Adhesion- attraction between molecules of
  different substances

Adhesion- Substance to glass (capillary action)
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Mixtures

• Mixture- a material composed of two or more
  elements or compounds that are physically mixed
  together but not chemically combined
• Mixtures (2 types)
• 1. Solutions Mixture that is evenly distributed
  throughout the solution
• Solute substance that is dissolved
• Solvent the substance in which the solute
  dissolves
• 2. Suspensions Substances that do not dissolve
  together but mix

Solution
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Mixtures

• Solution
• Solute- NaCl
• Solvent- water

NaCl Dissolving in Water When an ionic compound
such as sodium chloride is placed in water, water
molecules surround and separate the positive and
negative ions.
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Mixtures

• Suspension
• Different particles not dissolved

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Water Properties

• 1. Powerful, versatile solvent due to polarity
• 2. Very Cohesive behavior (due to H bonds holding
  water together)
• 3. High Surface Tension
• 4. High Specific Heat
• 5. High Boiling Point High Heat of
  Vaporization
• 6. Good evaporative coolant
• 7. High freezing point and lower density as a
  solid than a liquid (density anomaly)

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Water Properties

• 1. Powerful, versatile solvent due to polarity

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Water Properties

• 2. Very Cohesive behavior (due to H bonds holding
  water together)

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Water Properties

• 3. High Surface Tension

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Water Properties

• 4. High Specific Heat

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Water Properties

• 5. High Boiling Point High Heat of
  Vaporization

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Water Properties

• 6. Good evaporative coolant

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Water Properties

• 7. High freezing point and lower density as a
  solid than a liquid (density anomaly)
• Water is less dense in a frozen state

Water
Benzene
This is unusual for most substances
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Acids and Bases
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pH Scale

• The pH Scale is a system designed by scientist to
  measure the amount of hydrogen ions (H) or
  hydroxide ions (OH-) in solution.
• The scale ranges from 0 to 14, with 7 being
  neutral or an equal number of H and OH-. Pure
  water is neutral allowing it to be a component of
  even really strong acids and bases.

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pH Scale
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Acids

• Acids are solutions that have a higher
  concentration of H ions and whose pH value
  falls below 7.
• Lemons vinegar Battery Acid

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Bases

• Bases are solutions that have a higher
  concentration of OH- ions and less concentration
  of H
• Bases have a pH value is above 7.
• Soaps and cleaners

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Neutral

• 7 on a pH scale neutral
• Pure water is neutral
• equal concentration of OH- ions and H ions

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Buffers

• Buffers are weak acids and bases that can react
  with strong acids or bases to prevent sudden
  changes in pH.