AIM: What are chemical and physical changes? What are chemical and physical changes?
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Transcript of AIM: What are chemical and physical changes? What are chemical and physical changes?
AIM: What are chemical and physical changes?
Differentiate the meaning of chemical change and physical change
AIM: What are chemical and physical changes?
Chemical changeChemical change
Physical changePhysical change
Chemical changeChemical change
Physical changePhysical change
AIM: What are chemical and physical changes?
Investigate:
Crumble a piece of paperCrumble a piece of paper
Rip a piece of paperRip a piece of paper
Burn a piece of paperBurn a piece of paper
What are the differences?What are the differences?
Crumble a piece of paperCrumble a piece of paper
Rip a piece of paperRip a piece of paper
Burn a piece of paperBurn a piece of paper
What are the differences?What are the differences?
AIM: What are chemical and physical changes?
List some examples of Physical Change
1.1. cutting, freezing, boiling cutting, freezing, boiling 2.2. does NOT produce a new does NOT produce a new
substancesubstance3.3. Commonly associated with the Commonly associated with the
phase change diagram phase change diagram 4.4. Solid liquid gasSolid liquid gas
1.1. cutting, freezing, boiling cutting, freezing, boiling 2.2. does NOT produce a new does NOT produce a new
substancesubstance3.3. Commonly associated with the Commonly associated with the
phase change diagram phase change diagram 4.4. Solid liquid gasSolid liquid gas
AIM: What are chemical and physical changes?
What Exemplifies a Chemical Change?
1.1. Materials combine to form a new Materials combine to form a new substancesubstance
2.2. Burning paperBurning paper3.3. Rusting IronRusting Iron
1.1. Materials combine to form a new Materials combine to form a new substancesubstance
2.2. Burning paperBurning paper3.3. Rusting IronRusting Iron
AIM: What are chemical and physical changes?
Digestion has both Physical and Chemical Changes
1.1. Chewing of food by teeth into Chewing of food by teeth into smaller piecessmaller pieces
2.2. Stomach/Small Intestine breaks Stomach/Small Intestine breaks down food into individual down food into individual molecules (fats, sugars, amino molecules (fats, sugars, amino acids)acids)
1.1. Chewing of food by teeth into Chewing of food by teeth into smaller piecessmaller pieces
2.2. Stomach/Small Intestine breaks Stomach/Small Intestine breaks down food into individual down food into individual molecules (fats, sugars, amino molecules (fats, sugars, amino acids)acids)
AIM: What are chemical and physical changes?
Definition
• Chemical change: The substances present at the beginning of the change are not present at the end; new substances are formed. The change cannot be “undone.”
AIM: What are chemical and physical changes?
Examples
• Physical Changes • Aluminum foil is cut in • Clay is molded into a new
shape.• Butter melts • Water evaporates from
the surface of the ocean.• a juice box in the freezer
freezes.• .Rubbing alcohol
evaporates on your hand
• Chemical Changes• Milk goes sour.• Jewelry tarnishes. • Bread becomes toast. • Rust forms on a nail left
outside.• Gasoline is ignited.• Hydrogen peroxide
bubbles in a cut.
AIM: What are chemical and physical changes?
Name at least 5 clues that would indicate there has been a chemical
change in matter. 1. color
2. energy change3. odor
4. Gas or precipitate (solid) produced 5. not easily reversed
AIM: What are chemical and physical changes?
PHYSICAL CHANGES
MELTING
• solid to liquid
• As the ice gains energy – more molecules vibrate
• eventually the bonds that form the ice crystals break and the ice melts.
FREEZING
• the reverse: looses thermal energy
• The molecule move about more slowly
• Eventually the ice crystal start to form
AIM: What are chemical and physical changes?
Vaporization
EVAPORATION
• Water slowly gains energy
• Gradually converts to gas
• “sweating”
BOILING
• Water rapidly gains energy
• Quickly converts to gas
Reverse of Vaporization is called CONDENSATION
AIM: What are chemical and physical changes?
Practice Quiz
• http://www.mrzimmerman.org/OnLineQuizPage/Chem%20Practice.htm