Download 3rd Nine Weeks Study Guide Earth + Space 6.6B Calculate density

3rd Nine Weeks Study Guide
Earth + Space
6.6B Calculate density to identify an unknown substance

Density is a physical property of matter that does not depend on the size or amount
of the sample.

Density is the mass per unit volume of a substance.

Common units of density are grams per milliliter (g/mL) or grams per cubic
centimeter (g/cm3). 1 mL = 1 cm3

Density is useful when identifying unknowns because it is a constant for a given
substance regardless of size of the sample.
o For example, the density of water is always 1.0 g/mL. The density of gold is
always 19.32 g/cm3 and the density of pyrite (fool’s gold) is always 5.01
g/cm3.

To calculate the density of a sample, divide the mass of the sample by its volume.

Density = mass ÷ volume
o Example: if you have a sample that has a mass of 27g and a volume of 9
cm3, the density is calculated as follows:
Density = mass ÷ volume
= 27g ÷ 9cm3
= 3 g/cm3

Mass can be measured using a triple beam balance. The unit of measure for a TBB
is the gram (g).

Volume of a regular shape can be found by multiplying its length, its width and its
height together (LxWxH). A common unit of measure of a solid is cm 3 (cubic
centimeter).

Volume of an irregular shape is measured using displacement.
o The volume of the object is the difference between the water before and after
the object is placed in water.
Initial volume = 30 mL
Final volume = 40 mL
Displacement = 10 mL
Volume of solid = 10 cm3
6.10A Build a model to illustrate the structural layers of Earth, including the inner
core, outer core, mantle, crust, asthenosphere, and lithosphere

The CRUST is the brittle, rocky outer layer of the Earth.
o Thinnest layer
o Least dense layer
o Made of elements of low mass  silicon and oxygen

Oceanic Crust is crust under the oceans. It is denser than continental crust.

Continental Crust is crust on land. It is thicker but less dense than oceanic crust.

The MANTLE is the thick middle layer in the solid part of Earth.
o More dense than either type of crust
o Made of rock that contains elements iron and magnesium
o Grouped into 4 layers  uppermost mantle, asthenosphere, upper mantle
and lower mantle

The LITHOSPHERE is the rigid layer containing solid and brittle rocks (made of
crust and uppermost mantle)

The ASTHENOSPHERE is the plastic layer within the mantle. The word plastic
refers to materials that are soft enough to flow. Rocks in the asthenosphere move as
slowly as fingernails grow.

The upper and lower mantle make up the largest layer of the Earth. The rock in
these layers are hotter than the layers above it, but high pressure prevents melting.

The CORE is the dense metallic center of Earth.
o Most dense layer
o Made of mostly iron and some nickel

The OUTER CORE is liquid due to different melting temperatures of the metals that
make it up.

The INNER CORE is a dense ball of solid iron crystals.
o Highest pressure, density and temperatures of all Earth layers.
Continental Crust
Oceanic Crust
Lithosphere
Asthenosphere
Upper Mantle
Mantle
Lower Mantle
Outer Core
Core
Inner Core