Properties of Water

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Properties of Water

• TSW describe the properties of water that make it
  essential to life on Earth

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What is water?

• H2Owhich means? 1 molecule of water has 2 atoms
  of Hydrogen 1 atom of Oxygen
• Water covers up to 75 of the Earths surface
  makes up 70-95 of all living cells!

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Atomic Structure

• 2H O ? H2O
• Each Hydrogen atom is held onto the Oxygen atom
  by a polar covalent bond

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Lets take it a step further

• Hydrogen
• Protons 1
• Neutrons 0
• Electrons 1
• Oxygen
• Protons 8
• Neutrons 8
• Electrons 8

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Types of Bonding

• Ionic
• Covalent
• Polar Covalent
• Hydrogen

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Ionic Bonding

• Forms when 1 or more electrons are transferred
  from one atom to another
• If P gt E ? () charge
• If P lt E ? (-) charge
• Example NaCl

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Covalent Bonding

• Forms when electrons are shared between atoms NOT
  transferred, the resulting structure is called a
  molecule
• Example HCl or H2

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Polar Covalent Bonding

• Forms when sharing occurs in an unequal manner
  (the molecule formed has no net charge)
• Opposite ends of the molecule are partially (-)
  partially () depending on the distribution of
  electrons
• Example H2O

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Good to know

• Covalent bonds are stronger than ionic bonds
• Covalent bonds do not dissociate in water

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Hydrogen Bonding

• Forms between water molecules
• H bonds to O-
• Easy to break
• Key Point The numerous special qualities of
  water are made possible by its ability to form
  multiple H bonds

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