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Physical and
Chemical
CHANGES
Physical changes are all about
energy and
states of matter
• In a physical change there is only a change of state—thermal energy is added or removed.
• The new substance has the same chemical properties as the old one.
• No new substance(s) are produced. • Physical changes can be reversed.
SOLIDS
_LIQUIDS_
GASES_
PLASMA
+ energy
+ energy
+ energy -energy
- energy
- energy
The Staircase of Phase Change
Subtracting energy slows molecule motion, causing matter to go back down the stairs to a lower energy level.
Adding energy speeds up molecule motion, causing matter to move up a
level on the stairs.
Chemical changes happen on a
molecular level.
•Plus, you cannot get the original materials back easily.
•In a chemical change one or more NEW substances are created.
•The new substance is different from the original.
•It has properties that are different than those of the starting materials.
Identify the following events as:
Physical Change
Ask yourself:1. Is the material still the
same basic material?2. Is it just a change of
state or phase?3. Is it really new or
different material?4. Can it be easily
reversed?
Chemical Change
Ask yourself:1. Are there any new or
different substances?2. Is the material different
from the original?3. Are the chemical properties
different?4. Can it be easily reversed?
glass breaking
hammering wood together to build a playhouse
melting butter for popcorn
separating sand from gravel
spoiling food
mixing Kool-Aid powder into water
bleaching your hair
fireworks exploding
squeezing oranges to make orange juice
frying an egg
pouring milk on your cereal
burning leaves
making salt water to gargle with
cream being whipped
burning toast
freezing chocolate covered bananas
melting Popsicles
cooking spaghetti
Glow Sticks
Cooking applesauce
Whipping cream
Adding milk to cereal
Burning leaves
Making frozen chocolate bananas
Hammering wood together
Bleaching your hair
Dissolving Kool-Aid in water
Spoiled food
Melting a popsicle
Breaking a glass
Exploding fireworks
Fourth of July Ashland, KY
Melting butter for popcorn
Cooking an egg
Separating sand and gravel
Burned toast
Squeezing oranges for juice
Quiz Time!
1. In a physical change there is only a change of state—_______ is added or removed.
2. The new substance has the same _________ properties as the old one.
3. No _____ substance(s) are produced.
4. Physical changes are easily ________.
Use these to complete the questions:Chemical Energy New Reversed
1. In a chemical change one or more _____ substances are created.
2. The new substance is different from the _________ substance.
3. It has properties that are _______ than those of the starting materials.
4. You _______get the original materials back easily.
Use these to complete the statements:Cannot Different New Original
The END