Matter – any substance that has mass and volume. Its amount
can be measured and it takes up space. All matter has the
property of inertia.
Matter can be described by its measurements:
Mass – measured on a balance in grams
Volume – measured in 3 different ways:
Rectangular solids – measure and multiply
Length x width x height (cm3)
Irregularly shaped objects – water displacement
The volume is the difference between the
original height in a graduated cylinder
and the new height after submerging the
object. Remember to read the bottom of the
meniscus (curved surface). (mL)
Liquids – pour into a graduated cylinder and read
the meniscus.
Density – a ratio of the amount of mass “packed” in a
certain amount of space. It measures how tightly packed the
particles are.
D = mass (in grams) / volume (in mL or cm3)
Density is defined as
- the amount of mass in a given volume or space
Density is:
- expressed in g/mL or g/cu. cm. (g/cm3)
- a physical property of matter
- is specific for all substances (all substances have
their own specific density)
- can be used to identify substances
- temperature and pressure can change specific
density but is still specific to the substance
To calculate Density
Mass (g)
_________________
Volume (m/L) or (cm3)
Think: How many grams of the substance are packed into
1 mL of space? Or how many grams are packed into 1 cm3 of
space?
Density is used to compare substances.
Water has a density of 1g/mL.
Substances that have a lower density will float in water.
Substances that have a greater density will sink in water.
Substances with a density very close will float at, near or
just under the surface of water.
Densities can be used to make predictions about how
substances will behave when placed together.