Physical Properties of Pure
Substances
Intensive vs. Extensive
Essential Standard
• 6.P.2 Understand the structure,
classifications and physical properties of
matter.
Clarifying Objective
• 6.P .2.3 Compare the physical properties of
pure substances that are independent of the
amount of matter present including density,
melting point, boiling point, and solubility to
properties that are dependent on the amount
of matter present to include volume, mass
and weight.
Essential Question
• What is an INTENSIVE property of a pure
substance?
• What is an EXTNESIVE property of a pure
substance?
• What is the main difference between
INTENSIVE & EXTENSIVE properties of pure
substances?
Pure Substance
• A Pure Substance is a
sample of matter that
has the same
COMPOSITION &
CHEMICAL PROPERTIES
• All Elements on the
Periodic Table & Water
are pure substances
Periodic Table
Physical Properties
• A physical property of a
substance is a property
that can be seen without
changing the substance
into another substance
• Examples include…
– Color
– Luster (shiny)
– Odor
Intensive Physical Properties
• Intensive Physical
Properties are those
properties that no matter
what size will ALWAYS BE
THE SAME
• Intensive Physical
Properties include…
①
②
③
④
Solubility
Density
Melting Point
Boiling Point
Solubility
• Solubility is the ability of
a substance to dissolve
• If the pure substance
cannot dissolve it is said
to be insoluble
• The faster a pure
substance dissolves the
more soluble it is
Solubility
• Solubility is Intensive as it
does not matter how
much of the substance
you have it will either
dissolve or it won’t
(INTENSIVE)
• The speed of dissolving
does not matter on how
much of the substance
you have it will still
dissolve at the same
speed
Solubility (Example)
• If you stir a cup sugar in
some water it disappears
into the water
• The sugar disappearing is
the sugar DISOLVING
making sugar soluble
• It doesn’t matter if you put
2 cups of sugar into water it
will still dissolve
• KOOLAID
Density
• Density is how COMPACTED
TOGETHER a substance is
(not how much something
weighs)
• A Bowling Ball is very dense
because the atoms are
COMPACTED TOGETHER
• A bulletin board made of
cork is not very dense
because the atoms are not
packed close together
Density
• Density is INTENSIVE
PHYSICAL property
because it DOES NOT
matter how much you
have it will still have the
same DENSITY
Density (Example)
• Bulletin Board is not very dense
• The atoms are far apart for a solid
• You can put a pin or thumb tack
into a bulletin board
• Now think of trying to put a pin
or tack into a BOWLING BALL
• You can’t because bowling balls
are too dense
Melting Point
• Melting Point is the
temperature at which
point a substance
begins to melt
• It is INTENSIVE because
it does not matter how
much of the substance
you have it will begin
melting at the same
temperature
Melting Point (Example)
• Lets use gold as an example of
a substance
• I can use it because it is a pure
substance that is on the
Periodic Table
• No matter how much gold you
have whether it be my
wedding ring or a car made
out of gold
• If you heat it to 1948 degrees
it will begin to melt
Boiling Point
• Boiling Point is the
temperature at which a
substance begins to boil
• Boiling Point is
INTENSIVE because it
doesn’t matter how
much of the substance
you have it will start
boiling when it hits its
boiling point
Boiling Point (Example)
• Lets use WATER as an
example
• Water will boil at 212
degrees
• It doesn’t matter if you
have a cup of water or a
bathtub of water as soon
as it reaches 212 degrees
it will start to boil
Extensive Physical Properties
• Extensive Physical
Properties are those
properties that DEPEND
ON THE AMOUNT OF
MATTER of the object
• Extensive Physical
Properties include…
① Volume
② Mass
③ Weight
Volume
• Volume is the AMOUNT
OF SPACE that a solid,
liquid or gas takes up
• Volume is EXTENSIVE as
it DOES DEPEND on the
amount of the sample
Volume (Example)
• Lets use a cup &
swimming pool for an
example
• Which one of these takes
up more space
• The one that takes up
more space will have a
GREATER/BIGGER
VOLUME (swimming pool)
Mass
• Mass is the amount of
MATTER a substance
contains & it never
changes
• Mass is EXTENSIVE as it
DOES DEPEND on how
big the sample is
Mass (Example)
• Lets us an elephant and a baby
as an example
• The larger the sample the
LARGER/BIGGER the mass
• Because the elephant is bigger
it will have more mass
• But don’t get confused it will
have the same mass no matter
where it is (Earth or Space)
Weight
• Weight is the FORCE OF
GRAVITY on an object
• Weight is EXTENSIVE as
it DOES DEPEND on
where the sample is
Weight
• This means the more
gravity in a place the
more the substance will
weigh (it will still have
the same mass though)
• Weight will change
depending on where
the substance is
because of GRAVITY
Weight (Example)
• We will use Earth & the
Moon as an example
• Where will a person weigh
more Earth or the Moon
• There is more GRAVITY
pulling us to Earth because
it is bigger it has a larger
GRAVITATIONAL PULL
• This means we will WEIGH
more there
EOG Questions
• How does 250 mL of water compare to 500 mL of water?
• A) They have the same melting point but different boiling
points.
• B) They have the same boiling point but different melting
points.
• C) They have the same volume but different densities.
• D) They have the same density but different volumes.
Important Points
• Properties of Pure
substances can be either
INTENSIVE or EXTENSIVE
• INTENSIVE means that no
matter how much or where
the substance is the
properties will be the same
• EXTENSIVE means that
properties depend on either
how big the sample is or
where the sample is
• There are 4 INTENSIVE
properties
①
②
③
④
Solubility
Density
Melting Point
Boiling Point
• There are 3 EXTNESIVE
properties
① Volume
② Mass
③ Weight