Properties of Matter
Physical & Chemical Changes
Physical Properties
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Physical properties are observable
Examples are:
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Mass
Volume
Density
Melting point
Boiling point
Hardness
Ability to conduct electricity
Physical State – solid, liquid, or gas
Physical Properties Help ID
Substances!
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A physical property can be used to identify
a substance – shape, color, odor, texture
Example: What is…
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Round
Orange
Smells rubbery
Bounces
A Basketball!!
Magic Eggs Demo
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Observe what happens to the two eggs….
What physical property caused one to float
and one to sink?
What is Density?
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Density is a measure of how much “stuff” is
contained in a certain volume of a substance.
A low density item is “light” in comparison to
something else of the same volume
Which is more dense? A or B?
Answer: B – there is more “Stuff” for the
same volume!
A
B
Online Lab
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Go to the website, click on Online Density
Lab and fill out the corresponding
worksheet.
Density Equation
D = m/V
D = density
M = mass
V = volume
Units!
Mass must be in grams
Volume may be in either cm3 (if it is a solid) or mL
(if it is a liquid)
Density = g/cm3 or g/mL
Example Problem #1
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You are given a cube made out of an
unknown substance. How would you
determine its density?
First you can measure one side – let’s say it is
2cm.
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Volume = l x w x h
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2 x 2 x 2 = 8 cm3
Then you can weigh it on a scale – let’s say its
mass is 240 g
D = m/V
D = 240g/8cm3
D = 30 g/cm3
Example Problem #2
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You are given a cylinder made of an unknown
substance. How would you determine its
density?
To find the volume you can drop it in a
cylinder of water and note the change in
volume – let’s say the water level rises 10 mL
Then you can weigh it on a scale – let’s say
the mass is 100g
D = m/V
D = 100g/10mL
D = 10 g/mL
Float or Sink?
Density determines whether an object
will float or sink.
 If an object is less dense than the
fluid it is immersed in, it will float
 If it is more dense, it will sink
 Demos:
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Review
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Give four examples of a physical property.
What is density?
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Remember that density is a physical property
and is unique to the matter – copper will have
the same density, no matter how big or small the
object is.
How do you find volume if the object is a
cube? A cylinder (round object)?
Time to practice using the density equation….
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Time for Labs!!
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Cylinder Lab
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Density Challenge
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Density Challenge #2
Chemical Properties
Chemical properties are related to the
elements that make up a substance.
 They are not as easy to observe a
physical properties
 Examples:
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Flammability
 Reactivity
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Physical vs. Chemical Properties
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Physical properties are
readily observable
Chemical properties can
only be observed as the
object is changing
Example – you do not
know if an object is
flammable until you set it
on fire!
Physical vs. Chemical Properties
Physical Properties Chemical Properties
Baking Soda
White Powder
Reacts with
Vinegar
Rubbing
Alcohol
Clear Liquid
Flammable
Red Food
Coloring
Red Color
Reacts with
Bleach to lose
its Color
Iron
Malleable
Reacts with
Oxygen
Changes of Matter
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Physical Change
 Affects one or more physical property,
but does NOT change the identity of
the substance
 Break a piece of chalk – it is still chalk!
Chemical Change
 The substance changes into an entirely
new substance with different
properties
 Not reversible (except by another
chemical reaction)
 Bake a cake – the cake is entirely
different from the batter – new
properties!
Physical or Chemical Change?
Cutting Your Hair
Physical
Rusting
Chemical
Boiling Water
Physical
Dissolving Salt in Water
Physical
Burning Wood
Chemical
Frying an Egg
Chemical
OK – one more Lab….