Fossil Fuels
Chapter 11.2
Fossil Fuels
1. Fossil
Fuels
a.Fuel formed from the remains of
living organisms, such as coal,
petroleum, and natural gas.
b.Fossil fuels consist primarily of
compounds called hydrocarbons.
Fossil Fuels
Hydrocarbons
i. Hydrocarbons are compounds made
up of atoms of carbon and hydrogen.
1.These compounds contain energy
originally obtained from sunlight by
plants and animals that lived millions
of years ago.
2.When hydrocarbons are burned, energy
is released as heat and light that we can
use.
Hydrocarbons
Coal Formation
2.
Formation of Coal
a. Coal is a dark colored, organic rock formed from
chemical and physical changes of plant material
over millions of years.
b. Carbonization is the process by which partially
decomposed trees and other plants are buried in
swamp mud and transformed into carbon.
i. The process of carbonization occurs when bacteria
consume the plant material and release methane and
carbon dioxide gas. When these gases escape the
swamp, only the carbon is left.
Types of Coal
3.
Types of Coal
a. Peat is the partial decomposition of
brownish–black plant remains. Peat is
the substance that all coal is formed
from.
b. The three main types of coal are lignite,
bituminous, and anthracite.
Peat
Lignite
i. Lignite is the first type of coal formed from the
peat. As layers of sediment cover the peat
depleting the oxygen so decomposition can’t
continue, they cause pressure, which squeeze out
the water and gas, which then becomes a denser,
brown lignite.
Lignite
Bituminous Coal
1.Subbituminous coal, also called black
lignite, is generally dark brown to black
coal, and falls between lignite and
bituminous coal.
ii. The added pressure of more
deposited sediments further
compresses the lignite to form
bituminous coal, or soft coal.
1.Bituminous coal is the most abundant type
of coal.
Subbituminous & Bituminous
Anthracite
iii. Where the folding of the earth’s crust produces
extremely high temperatures and pressure,
bituminous coal is changed into anthracite, the
hardest of all coal.
iv.Bituminous coal and anthracite consists of 80%
to 90% carbon, which makes them a great energy
resource.
Anthracite
Petroleum & Natural Gas
4.
Petroleum and Natural Gas
a. Petroleum and natural gas are
mixtures of hydrocarbons.
i. Petroleum oil consists of liquid
hydrocarbons.
ii. Natural gas consists of gaseous
hydrocarbons.
Formation of Petroleum & Gas
b. Formation of petroleum and Natural
Gas
i. When microorganisms died in shallow
prehistoric oceans and lakes, their remains
accumulated on the ocean floor and lake
bottoms which were then covered and
buried by sediment.
Formation of Petroleum & Gas
ii. As the amount of sediments
increased, so did the heat and
pressure on the
microorganisms. This added
heat and pressure was enough
to cause a chemical change to
form petroleum and natural gas.
Deposits of Petroleum & Gas
5. Petroleum
and Natural Gas
Deposits
a. Sedimentary rock has many
interconnected spaces between the
rock particles. This allows liquids
and gases to flow freely through
the rock.
Deposits of Petroleum & Gas
b. As sedimentary rock becomes deeply
buried under overlying sediments,
pressure increases. This increasing
pressure causes the water and
hydrocarbons out of the rock and up
through the layers of permeable rock
until they come to a layer of
impermeable rock.
i. This impermeable layer of rock is called
cap rock.
Deposits of Petroleum & Gas
c. The water, oil, and natural gas
separate under the cap rock due to
their densities. Natural gas is less
dense, then oil, then water.
d. Rock that liquids can easily flow
through is called permeable rock.
e. Rock that liquids cannot easily flow
through is called impermeable rock.
Deposits of Petroleum & Gas
f.
Crude oil is unrefined oil and has many
uses. Petrochemicals are chemicals derived
from petroleum and are the main
component in over 3,000 products.
i. These products include plastics, synthetic fabrics,
medicines, tars, waxes, synthetic rubber,
insecticides, chemical fertilizers, detergents, and
shampoos.
Fossil Fuel Supplies
6.
Fossil Fuel Supplies
a. Fossil fuels are a nonrenewable resource.
b. Coal is the most abundant fossil fuel in the
word, occurring on every continent.
i. While coal is very abundant, scientists predict that
world wide coal reserves will only last another
200 years.
ii. However, two-thirds of it are deposited in three
countries: the US, Russia, and China.
Fossil Fuel Supplies
c. Scientists estimate that 75% of all
the petroleum in the US has
already been discovered,
however, much of the
undiscovered supply is thought to
be under the ocean floor along the
edges of North America.
Fossil Fuels & the Environment
7.
Fossil Fuels and the Environment
a. The use of any fossil fuels has an impact on
the environment.
i. Strip mining
1. Strip mining coal leaves deep ditches where coal is
removed
2. Rocks and topsoil that are displaced to expose the coal
are left in steep slopes, and without plants and topsoil
to protect it, the exposed land will weather away.
Fossil Fuels & the Environment
3. Wet rocks that are exposed during
mining can give off acids.
a.These acids can be carried to nearby
rivers and streams causing harm to
aquatic life.
4.Since strip mining can be so damaging
to the environment, the US government
has place many regulations to decrease
and/or prevent the damaging of our
environment.
Air Pollution
ii. Air Pollution
1.The burning of any fossil fuel
causes pollution in the air. While
some fuels may be less damaging
such as natural gas, they do still
pollute the environment.
a.Much of this air pollution can
contribute to acid rain
Spills
iii. Spills
1. Fossil fuel spills happen
rarely, but have a huge and
sudden impact on the
environment when they do.
a.Examples include spills
from wells, tankers, and
pipelines.