Solving the Chemistry Puzzle

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Solving the Chemistry Puzzle

• Chemical and Physical Changes

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Lets Review Matter

• PURE SUBSTANCE vs. MIXTURE
• Pure Substance (same stuff, definite proportions)
• Elements Gold, carbon, oxygen, etc. (see the
  Periodic Table)
• Compounds Sugar, salt, water, etc.
• Mixture (pure substances come together to form
  mixtures variable proportions)

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Matter has PROPERTIES

• PHYSICAL vs. CHEMICAL
• Physical Properties
• Color, shape, odor, texture, density
• Chemical Properties
• Ability to react with other things

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How Can Matter Change?

• Wood rots. Snow melts. Cookies crumble. Paint
  fades. Buildings collapse. Fireworks explode.
• Some changes are physical, others are chemical
• Changes can be fast or slow.

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Lets Start withPHYSICAL CHANGES

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Physical Changes

• Examples of physical changes
• Tearing paper
• Crushing chalk
• Melting ice
• Bending a metal bar

NOTHING NEW IS CREATED!!!!
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Now, CHEMICAL CHANGES

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Chemical Changes

• Examples of chemical changes
• Burning paper or wood
• Dissolving chalk
• Rusting a metal bar
• Digesting food
• Cooking eggs, caramelizing sugar

NEW SUBSTANCES ARE CREATED!
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How can you detect a CHEMICAL CHANGE?

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Look for Evidence!

• Evidence of chemical changes
• Color change or a new color
• Light or heat are given off
• Bubbles, bubbles, bubbles! (gas)
• Phase change (be careful this happens in
  physical changes, too)

THESE ARE HARD TO REVERSE!