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Unit 3 – Classification of Matter
Chemistry 11
Sec 3.5
Chemical and Physical Changes
Chemical Change – a new substance is formed
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Burning (combustion)
Explosions
Cooking food (not just warming it up)
Digestion
Photosynthesis
Clues that a Chemical Change has occurred:
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A new colour may appear
Heat or light may be given off
Bubbles of gas may be formed (not boiling)
Solid material may form in a liquid (clear turns cloudy)
The change may be difficult to reverse
Note – some of these can happen with a physical change
Physical change – ONLY a phase change takes place, NO new chemical is
formed
Chemistry 11
Unit 3 – Classification of Matter
Other Physical changes could include things like:
- Mixing
- Dissolving
Identify each as either a chemical change or a physical change
a. Rusting
- ____________________
b. Burning of steel
- ____________________
c. Melting butter
- ____________________
d. Blowing up a balloon
- ____________________
e. Hydrogen exploding
- ____________________
f. Calcium in water
- ____________________
g. Salt dissolving
- ____________________
h. Color fading in the sun
- ____________________
i. Nerve transmissions
- ____________________
j. Tanning of the skin
- ____________________
Chemistry 11
Phase change graph
Unit 3 – Classification of Matter
Unit 3 – Classification of Matter
Chemistry 11
Sec 3.5
Chemical and Physical Changes
Chemical Change – a new substance is formed





_________________________
_________________________
_________________________
_________________________
_________________________
Clues that a Chemical Change has occurred:





A ________________ may appear
______ or ______ may be given off
Bubbles of ______may be ____________ (not boiling)
Solid material may form in a liquid (clear turns cloudy)
The change may be ________________________
Note – some of these can happen with a physical change
Physical change – ONLY a phase change takes place, NO new chemical is
formed
Chemistry 11
Unit 3 – Classification of Matter
Other Physical changes could include things like:
- ____________
- ____________
- Electric light bulb glowing
Identify each as either a chemical change or a physical change
k. Rusting
- ____________________
l. Burning of steel
- ____________________
m. Melting butter
- ____________________
n. Blowing up a balloon
- ____________________
o. Hydrogen exploding
- ____________________
p. Calcium in water
- ____________________
q. Salt dissolving
- ____________________
r. Color fading in the sun
- ____________________
s. Nerve transmissions
- ____________________
t. Tanning of the skin
- ____________________
Chemistry 11
Phase change graph
Unit 3 – Classification of Matter