P1249945250WBNRh

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Chemistry of Life
Chapter 6.1 Atoms their interactions
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Units of Matter ..

• Atoms
• Elements
• Compounds Molecules

• C, O, H, N, S
• CO2, H20, C6H1206

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Common Molecules
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Atoms of the same Element

• Same number of protons, electrons neutrons
• Same atomic structure

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Atoms

• Germanium Ge
• Tunneling Microscope
• Computer enhancement

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Atomic Models
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Rules for Bohr model

• Atomic number
• electrons
• protons
• 1st shell 2 paired electrons
• 2nd shell up to 8
• 3rd shell up to 8

• (-, outer shell)
• (, nucleus)

ee
Nucleus 2P,N
He
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Ions

• Atoms that
• Loose or
• Gain
• Electrons

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Ionic Bonds
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Covalent BONDS

• Share electrons
• Stronger than ionic that
• Donate or Gain electrons

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pH

• ? pH
• ? pH scale
• ?affect us
• ?pH balanced shampoo

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WATERH2 O

• How many atoms?
• ?Types of bonds?
• ?Strong or Weak
• ? Break

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Water molecule...

• Covalent bonds
• Polar
• charge at O end
• - charge at H end
• Pull apart ions

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H2O--gtH OH-

• H Hydrogen ion
• in excess acid
• OH- Hydroxide ion
• in excess base

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How frequently do they break apart?

• (10)-7 concentration of H
• .0000001
• 1 for every 10 million water molecules!

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pHmeasurement

• -log of the H
• for water
• (10)-7
• pH 7

pH 2 pH4 pH8 pH10 pH12
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?H20 a neutral pH

• hydrogen ions hydroxide ions.
• H (10)-7
• OH- (10)-7

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?Makes an acid

• Increase the relative amount of H
• adding a weak acid
• H 10-5
• ? pH
• pH 5

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?Base

• H lower than 10-7
• tips the balance of H to OH-
• more OH- than H.
• base with pH 8
• alkaline

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?strong or weak

• The more acid the __________the pH number.
• (lower) (1-5)
• The more alkaline, the ________________ the pH
  (higher, above 7) (8-12)

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Examples

• Lemons
• Vinegar
• Aspirin
• Battery acid
• sour

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Bases

• Ammonia
• Lye
• Sodium hydroxide
• Baking soda
• slippery

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? living systems pH challenges?

• ? is low body pH
• ?extreme pHs cells
• ?spills of strong acids or bases on your hand?

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?BUFFERS

• ?buffered asprin
• buffers take up excess H or OH- ions
• maintain constant pH
• blood Homeostasis
• CO2 H2O H2CO3