Chapter 2-2
Physical Properties of Matter
Physical Properties
• A physical property of matter can be
observed or measured without changing
the matter’s identity.
• Some examples of physical properties are
state (phase), density, solubility, ductility,
malleability, magnetism, and ability to
conduct electricity.
Physical Properties
• State (or phase) is the physical form in
which a substance exists.
• The states of matter are solid, liquid, gas,
or plasma.
• Density is the mass per unit volume of a
substance.
• Solubility is the ability of a substance to
dissolve in another substance.
Physical Properties
• Ductility is the ability of a substance to be
pulled into wires.
• Malleability is the ability of a substance to
be rolled or pounded into thin sheets.
Ductility & Malleability
Density
• Density is a physical property that
describes the relationship between mass
and volume.
• Density is the amount of matter in a given
space, or volume.
• A golf ball and table-tennis (ping-pong)
ball have similar volumes but the golf ball
is denser because it has a greater mass.
Density
• In Figure 4, page 46, why do you think maple
syrup is on the bottom of the six liquids? Why
do you think corn oil is on the top?
• The denser liquids sink to the bottom of the flask.
The less dense liquids rise to the top.
• The order in which the layers separate shows the
order of increasing density.
Density
Density
• Knowing the density of a substance will
tell you if the substance will float or sink in
water.
• The density of water (at 4°C) is 1.00 g/cm3.
• If an object is less dense than water it will
float in water.
• If the object is more dense than water it
will sink.
Density
Solving for Density
• Density (D) is found by dividing mass (m)
by volume (V).
• Units for density consist of a mass unit
divided by a volume unit.
• Common units for density are g/cm3, g/mL,
kg/m3, and kg/L.
Using Density to ID Substances
• Each substance has a density that differs
from the densities of other substances.
• The density of a substance is always the
same at a given temperature and pressure.
• What is the density of Helium gas?
• 0.00001663 g/cm3
• Write this in scientific notation.
• 1.663 x 10-5 g/cm3
Using Density
• What is the density of Mercury (the only
liquid metal at room temperature)?
• 13.55 g/cm3
• Read the Math Focus section of page 47.
Try the three sample questions.
Using Density
• What happens to the density of an object if
the object is cut in half? Why?
• The density remains the same because
cutting the object in half will divide the
mass & volume by the same amount. Also,
the density of a substance remains the
same no matter what size it is. All matter
has its own unique density.
Interesting Density Fact
• The density of a fresh egg is about 1.2 g/mL, and
the density of a spoiled egg is about 0.9 g/mL.
The density of the egg decreases as it ages
because as it spoils, it loses water through the
tiny pores in the shell.
• What would happen to a fresh egg if placed
in a beaker of water? What would happen
to a spoiled egg?
Physical Changes
• A physical change is a change that affects one or
more physical properties of a substance.
• Freezing water to make ice or sanding a piece of
wood are examples of physical changes.
• Physical changes do not change the
identity of the matter involved, only some
of the physical properties.
Phase Changes are Physical
Changes