Do Now 11/4/10 FWhat will happen to the dollar? Why?
Matter can be changed in 2 ways FPhysical Changes FChemical Changes FPhysical Changes FChemical Changes
What are Physical Changes? Physical Changes: 1) Atoms do not rearrange 2) Generally easy to reverse. 3) Only physical properties change. 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 Change in: 1.Color 2.Mass 3.Volume 4.Density
More Examples… 5. Size 6. Luster or “Shine” 7. Shape 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) 8. Texture (the feel of something) 9. State of matter (Solid, Gas, or Liquid)
Guess that Change
Grinding Wood on a spinning saw Is the composition of this wood changing? What IS changing?
What changes? Wrecking a car
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
-Reaction with Oxygen in the airExamples: Rust (cars, apples) Tarnish (jewelry) Statue of Liberty Oxidation
The Statue of Liberty, 1886
The Statue of Liberty, 2010… What happened?
This boat has OXIDIZED!
-Flames produce black ash Examples: Wood burns and turns to ash Water does not burn
The Burning Dollar example Revisited FDescribe the physical properties of the two ingredients. FNow, describe the chemical properties of the two ingredients. FWhich ingredient is flammable? FWhich ingredient is NOT flammable? FNow, use your new science knowledge to explain the science behind the experiment! FDescribe the physical properties of the two ingredients. FNow, describe the chemical properties of the two ingredients. FWhich ingredient is flammable? FWhich ingredient is NOT flammable? FNow, 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. -Reaction with fire and produces CO2 gas. Example Metal car burning. Black smoke (CO2 gas) is released.
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! 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!