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Do Now 11/4/10. What will happen to the dollar? Why?. Matter can be changed in 2 ways. Physical Changes Chemical Changes. What are Physical Changes ?. Physical Changes: 1) Atoms do not rearrange 2) Generally easy to reverse . 3) Only physical properties change. .
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Do Now 11/4/10 • What will happen to the dollar? Why?
Matter can be changed in 2 ways • Physical Changes • Chemical Changes
What are Physical Changes? Physical Changes: 1) Atoms do not rearrange 2) Generally easy to reverse. 3) Only physical properties change.
Sign of a Physical Change Change in: 1.Color 2.Mass 3.Volume 4.Density
More Examples… 5. Size 6. Luster or “Shine” 7. Shape
And More Examples…. 8. Texture (the feel of something) 9. State of matter (Solid, Gas, or Liquid)
Grinding Wood on a spinning saw Is the composition of this wood changing? What IS changing?
Wrecking a car What changes?
Melting ice cream… What is changing?
Bending Wire… What is changed when we bend it?
Chemical Changes 1) Atoms DO rearrange. 2) CANNOT be reversed. 3) Something entirely new is created. 4) Chemical Formula changes
Oxidation • -Reaction with Oxygen in the air • Examples: • Rust (cars, apples) • Tarnish (jewelry) • Statue of Liberty
Flammability • -Flames produce black ash • Examples: • Wood burns and turns to ash • Water does not burn
The Burning Dollar exampleRevisited • Describe the physical properties of the two ingredients. • Now, describe the chemical properties of the two ingredients. • Which ingredient is flammable? • Which ingredient is NOT flammable? • Now, use your new science knowledge to explain the science behind the experiment!
Combustibility -Reaction with fire and produces CO2 gas. Example Metal car burning. Black smoke (CO2 gas) is released.
Reactivity with Acid Reacts with acid and produces gas bubbles or heat Example: Baking soda + Vinegar
Example of a Penny reacting with acid… Penny + Nitric Acid
Formation of a Precipitate (Powder) Example Adding colorless sodium chloride to colorless silver nitrate produces a white precipitate.
Summary Physical Changes -Don’t produce something new - are reversible. Chemical changes -Produce something new -Change the identity of the raw materials -Are irreversible -Are exciting to watch!