Physical or Chemical Change You decide

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Chemical Physical Changes
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Law of Conservation of Matter

• Matter can not be created or destroyed!
• Matter can only change forms!

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Physical change The material itself is the same
before and after the change. The change can be
undone.
                              Ice melting an
example of physical change.
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Physical Change

• Ripping Paper

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Origami
The form/shape may change, but you still have
paper
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Physical Change
You still have bronze!
Melting bronze into a liquid
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Ghost Crystals (crosslinked polyacrylamide)
water
Physical reaction!! Given time the water will
evaporate away and leave the crystals
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Sodium Polyacrylate
Theses crystals are found in the "super absorbent
layer" in most disposable diapers.
If left to dry long enough, it would return to
its original state or appearance.
It can absorb 200 to 300 times its weight in tap
water
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Instant Snow
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Cracking an Egg
Beating an Egg
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Physical Change Review

• Only the state of matter changes
• NO new substances are formed!
• All Phase changes are physical changes!

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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.
A nail rusting an example of chemical change.
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Evidence of a Chemical Change

• Color Change
• Bubbling (formation of a gas)
• Light
• Temperature change
• Precipitate

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Raw Egg Fried Egg
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Chemical Change! The proteins in the egg have
changed! The cooked egg cannot change
back to a raw egg.
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Chemical Reaction!Your body chemically reacts
with the food you eat to make nutrients and
energy!
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Chemical Change! Rust is a new substance! (color
change)
Car with rust
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Chemical Reaction!Formation of a Precipitate

• lead iodide (PbI2), forms from the mixture of two
  clear liquids,
• potassium iodide (KI) and
• lead nitrate (Pb(NO3)2).

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Chemical Reaction!Formation ofLight HeatGas
Reaction of bromine phosphorus.
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Yellow BlueSwitcheroo
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Yellow BlueSwitcheroo
Oscillating Reaction
Chemical! Color Change indicates the chemical
properties of the indicator were changed!
New product formed! Cant be reversed!
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Pour a Rainbow
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• Acids to a Base Reactions
• Color change Polymerization

A Chemical Change Occurs!!
We have now made our own slime!
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Old Foamy
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Old Foamy
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Chemical Change

• Old Foamy
• Hydrogen Peroxide Sodium Iodide Solution
• With Dishwashing Detergent
• New product formed!
• Cant be reversed!

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Chemical Change Review

• A chemical reaction occurs
• New substance(s) are formed with NEW properties
• It can not be reversed!

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Whoosh Bottle
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Chemical Change

• Exothermic Reaction
• O2 Combustion ?CO2 H2O
• Color Heat released
• New product formed!
• Cant be reversed!

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