Transcript Power Point on Matter (yellow)

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Physical Change
“The physical properties of a
substance change, but the identity
of the substance does not change.”
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Chemical Properties
• A chemical property
is any characteristic
that gives a
substance the ability
to undergo a change
that results in a new
substance.
• 4 Examples of
chemical properties:
–
–
–
–
Reacts to water
Reacts to light
Reacts to oxygen
Flammability
Chemical Change
“A change in the identity of a
substance due to the chemical
properties of that substance. A NEW
substance or substances are
formed as a result of the change.”
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Signs of a Chemical Change
Bubbles
Production of Heat
Light
Smoke
Change in Color
Sound
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Is a chemical change
reversible?
• A chemical change can only be reversed
by a chemical reaction, not by physical
means.
Are these examples
chemical or physical
changes?
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A Rusting Bicycle
ANSWER
Chemical Change
Oxygen in the air
reacts with the metal
of the bicycle.
This produces a new
substance called rust.
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Melting Butter
for Popcorn
ANSWER
Physical Change
Heating causes
the butter to
change from a
solid to a liquid.
The identity of the
butter does not
change.
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Hammering Wood
Together to Build a
Birdhouse
ANSWER
Physical Change
Hammering the
wood together
causes the wood
to change shape.
The identity of the
wood does not
change.
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Spoiling Food
ANSWER
Chemical Change
Spoiling food
changes color and
has a foul odor.
Bacteria, mold,
enzyme action, and
oxidation cause
spoilage.
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Mixing Lemonade
Powder into Water
ANSWER
Physical Change
After mixing the
lemonade powder
and water, lemonade
powder and water are
still present.
Evaporating the water
separates the
ingredients.
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Mowing the Lawn
ANSWER
Physical Change
Cutting the
grass does not
change the
identity of the
grass.
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Fireworks Exploding
ANSWER
Chemical Change
Fireworks are
composed of different
metals, such as
copper.
After ignited, the
fireworks produce
light, heat, and sound.
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Water Boiling
ANSWER
Physical Change
When water boils,
water changes from
a liquid to a gas.
The identity of the
water does not
change.
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Photosynthesis
ANSWER
Chemical Change
Plants change
carbon dioxide,
water, and
sunlight into sugar
and oxygen.
New substances
are formed.
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Separating a Mixture
of Rocks and Sand
ANSWER
Physical Change
Separating the
rocks from the sand
can be done by
physical means.
The identities of the
rocks and sand do
not change.
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Adding
Food Coloring
to Water
ANSWER
Physical Change
The identities of the
substances did not change.
Water and food coloring are
still present.
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Adding
Vinegar to
Baking Soda
ANSWER
Chemical Change
Gas bubbles were
produced.
The baking soda and
vinegar reacted to form
bubbles of carbon dioxide.
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Can HEAT cause a chemical
reaction?
YES !
Can LIGHT cause a
chemical reaction?
YES,
Photosynthesis
What is a sign of a physical
change?
A change in a physical property:
•Shape, size, length,
• change phase (solid,
liquid, gas)
SIGNS OF A CHEMICAL
CHANGE:
•HEAT
LIGHT
•SMOKE
BUBBLES
•COLOR CHANGE
•SOUND
•NEW IDENTITY
•CAN’T BE REVERSED BY
PHYSICAL MEANS
What is….?
A change in the identity of a
substance due to the
chemical properties of that
substance.
Chemical change
What is….?
Any characteristic of a
material that can be
observed or measured
without changing the identity
of the material.
Physical property
Any characteristic that
gives a substance the
ability to undergo a
change that results in a
new substance.
Chemical Property
What is….?
Any characteristic of a
material that can be
observed without changing
the identity of the material.
Physical Property
Examples of Physical
Properties:
Boiling point
Melting point
Volume
Density
Color
freezing point
shape
length
Mass
Examples of Chemical
Properties:
Flammability
Reacts with oxygen
Reacts with H20
Ability to change with light
A ___________change
results in a new
substance, with a
new…. IDENTITY