The Properties of Water

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The Properties of Water
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The Mickey Mouse Molecule!
Hydrogen
Hydrogen
Oxygen
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Structure of a Water Molecule

• Water is polar.
• A polar molecule is a molecule that has an
  electrical charge.
• Water is made of
• 2 Hydrogen Atoms and 1 Oxygen atom.
• The chemical formula for water is H2O
• Hydrogen has a positive () charge and Oxygen has
  a negative (-) charge.

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4 Key Properties of Water

• Capillary Action
• Surface Tension
• Universal Solvent
• Specific Heat

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Capillary Action

• Capillary action is the combined force of
  attraction among water molecules and with the
  molecules of surrounding materials.
• Examples of Capillary Action of Water
• Liquid rising inside a straw
• Paper towel absorbing water
• Wet jeans
• Plant roots absorbing water
• Sponge

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Surface Tension

• Surface tension is the tightness across the
  surface of water that is caused by the polar
  molecules pulling on one another
• Examples of the surface tension of water
• Raindrops forming beads on surface
• Water strider
• Paperclip Floating on Water
• Drops of Water on a Penny
• Skipping Rocks
• Meniscus
• Belly Flops

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Jesus Lizard
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Water Strider
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Universal Solvent

• Solution A mixture that forms when one
  substance dissolves another.
• Solvent substance that does the dissolving.
• Solute substance that gets dissolved.
• Water is the universal solvent because it
  dissolves so many substances because of its high
  polarity.
• Water can dissolve substances such as salt and
  sugar but cannot dissolve oil.
• - Polar Dissolves Polar.

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Specific Heat

• Water requires a lot of heat (gain or loss) to
  change its temperature due to the strong
  attraction among water molecules.
• Specific heat is the amount of heat needed to
  increase the temperature of a substance by 10C
• Example of specific heat
• - Water temperature vs. sand temperature at the
  beach during the day.

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Why does water have a high specific heat?

• Waters high specific heat is due to the strong
  attraction among water molecules.
• The molecules are stuck together and it takes a
  lot of energy to break the strong bonds of the
  water molecules.

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Changing State

• Water exists in 3 forms
• solid
• liquid
• gas

solid
liquid
gas
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Molecule Movement

• Molecules move the slowest in a solid.
• Solid-molecules are close together
• Molecules move the fastest in a gas.
• Gas-molecules move freely they are spread apart

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Phase Changes

• Melting-water changes from a solid to a liquid
• Example Ice melts into water
• Freezing-water changes from a liquid to a solid
• Example Water freezes into ice

Melting
Solid
Liquid
Freezing
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Phase Changes

• Evaporation- process by which molecules at the
  surface of a liquid absorb enough energy to
  change to the gaseous state
• Example boiling water, hair air-drying, wet
  clothes drying on a clothesline outside, puddle
  drying up
• Condensation-process by which a gas changes to a
  liquid
• Example water droplets on the outside of a
  glass
• fogging up a window

Evaporation
Gas
Liquid
Condensation
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Phase Changes
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Phase Change Diagram