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Carlyn LeGrant
Energy Unit Exam Study Guide
Laws of Thermodynamics:
● First: Energy in universe is constant, cannot be created nor
destroyed
● Second: Everytime energy is transfered some is
lost in the process
Plate Tectonics:
● process that underlies
earthquakes and volcanoes and that
determines the geography of the
Earth’s surface
● Pangaea = at least twice in
Earth’s history, all landmasses were
joined in one supercontinent
● Plate Boundaries: See figures
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The Rock Cycle:
The heating, melting, cooling, breaking and
reassembling of rocks and minerals. Rocks help
determine soil chemistry, which influences
ecosystems
Mineral vs. Rock: (Mineral- naturally occurring,
inorganic, solid element or compound with a
definite chemical composition and a
regular internal crystal structure; RockEach rock type has a characteristic
mixture of minerals, aggregate of multiple
minerals)
Igneous Rock:
○ Magma = the molten, liquid state of
rock
○ Lava = magma released from the
lithosphere
○ Igneous rock = forms when magma cools
○ Intrusive rock = magma that cools slowly well below Earth’s
surface (i.e., granite)
○ Extrusive rock = magma ejected from a volcano (i.e.,
basalt)
Sedimentary Rock (dissolved minerals seep through sediment layers
and crystallize and bind sediment particles together)
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Sediments = particles
of rock are blown by
wind or washed away by
water
○ Lithification =
formation of rock
through the processes
of compaction, binding,
and crystallization
Metamorphic Rock: (great
heat or pressure on a rock
changes its form)
○ Temperatures is high
enough to reshape
crystals and change its
appearance and physical properties
○ Examples include Marble (Heated and pressurized limestone)
and Slate (heated and metamorphosed shale)
● Ore is an economically exploitable
deposit
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Issues of mining:
○ Disruption of land surface
○ Subsidence
○ Erosion of solid mining waste
○ Acid mine drainage
○ Air pollution
○ Storage and leakage of liquid
mining waste
○ Gaping holes in ground (old
open pit mines).
○ Particulate air pollution
○ Piles of mine tailings (nonore removed from mines).
○ Accidental draining of rivers and lakes.
○ Disruption of groundwater flow patterns.
○ Loss of topsoil in strip-mined regions
○ Contamination from sulfuric acid
Gangue is a worthless mineral that is associated with the
valuable minerals in an ore
Surface Mining Control and Reclamation Act (1977)- Mine lands
must be restored to pre-mining conditions, Taxes on mining
companies to restore pre-1977 sites. Came w/ limited success
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Mine
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Reclamation:
Recontouring land back to its original topography
Improve soil quality by adding topsoil / nutrients
Replanting with native, fast growing, early successional
species, Monitor the site for 5 – 10 years
○ More difficult in arid areas b/c difficult to grow
vegetation
Fossil Fuels:
● Fossil Fuels are highly combustible
substances formed from the remains of
organisms. We get a lot of our energy
from them (dominant source) and from
the Solar radiation, geothermal and
nuclear
○ The high-energy content of fossil
fuels makes them efficient to
burn, ship, and store
○ These fuels generate electricity = a
secondary form of energy that is
easier to transfer and apply to a
variety of uses
● Disrupt the carbon cycle by releasing
carbon dioxide, the greatest
impact of fossil fuel use
● Pollutants and
hydrocarbons cause severe health problems
● Contaminates water and freshwater ecosystems
● Renewable vs. Non renewable
● Fossil fuel reserves are unevenly distributed
(People in developed regions consume far more energy
than those in developing nations)
Coal = organic matter (woody plant material) that
was compressed under very high pressure to form
dense, solid carbon structures. The world’s most
abundant fossil fuel. Coal is used to generate
electricity
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Subsurface mining = underground deposits are reached by digging
networks of tunnels deep
underground
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open pit miningcircular hole in ground, with ramp
circling down along sides, allows
deeper ore to be reached.
● Strip mining = heavy
machinery removes huge amounts of
earth to expose and extract the
coal
● Mountaintop removal = in
some cases, entire mountaintops
are cut off to obtain the coal
● Additional pressure turns
peat into coal. Then comes, Lignite = least compressed, Subbituminous and
bituminous,
Anthracite = most
compressed; has
the most energy
○ When
high-sulfur coal
is burned, it
released sulfate
air pollutants,
which contribute
to smog and acidic
deposition
Natural Gas
● The fastest
growing fossil fuel in use today. Provides 25% of global
commercial energy consumption
Natural gas = consists of methane (CH4) and other volatile
hydrocarbons, Most accessible reserves have been depleted, Gas is
accessed by sophisticated techniques such as fracturing, which
pumps high-pressure salt water into rocks to crack them
Offshore drilling produces much of our gas and it takes place on
land and in the seafloor on the continental shelves
Oil (U.S. consumes 25% of the world’s oil)
● Oil is the world’s most used fuel since the 1960s, and it’s
worldwide use over the past decade has risen 17%
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Crude oil (petroleum) = a mixture of hundreds of different types
of hydrocarbon molecules (It is put through a boiler/ refining
process to segregate different components.)
Formed 1.5 - 3 km (1-2 mi) underground, because dead organic
material was buried in marine sediments and transformed by time,
heat, and pressure
Drilling includes:
○ Primary extraction = the initial drilling and pumping of
available oil
○ Secondary extraction = solvents, water, or stream is used
to remove additional oil; expensive
○ We lack the technology to remove every bit of oil
○ As prices rise, it becomes economical to reopen a well
● Proven recoverable
reserve = the amount of oil
(or any other fossil fuel)
that is technically and
economically feasible to
remove under current
conditions
● ***U.S. oil production
has already peaked
● Oil sands (tar sands) =
sand deposits with 1 - 20%
bitumen, a thick form of
petroleum rich in carbon,
poor in hydrogen vs. Oil shale = sedimentary rock filled with
kerogen (organic matter) that can be processed to produce liquid
petroleum
OPEC’s (Organization of Petroleum Exporting Countries) oil
embargo caused widespread panic and skyrocketing prices
Energy:
● Net energy = energy returned–energy invested
● Energy returned on investment (EROI) = energy returned/energy
invested (Higher ratios mean we receive more energy than we
invest)
○ Ratios decline when we extract the easiest deposits first
and now must work harder to extract the remaining reserves
● Types of Energy: (Potential)
○ Chemical Energy is the energy stored in the bonds of atoms
and molecules. Biomass, petroleum, natural gas, propane,
and coal are examples
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Nuclear energy is the energy stored in the nucleus of an
atom- energy that holds the nucleus together (Uranium)
○ Store mechanical energy- is energy stored in objects by the
application of force. Compressed springs and stretched
rubber bands are examples
○ Gravitational Energy- Energy of place or position. Water in
a reservoir behind a hydropower dam is an example
Types of Energy (Kinetic)
○ Radiant energy- electromagnetic energy that travels in
transverse waves. Solar energy is an example
○ Thermal energy- or heat is the internal energy in
substances, the vibration or movement of atoms and
molecules in substances. Ex. Geothermal
○ Motion- is the movement of a substance from one place to
another. Ex. Wind and hydropower
○ Sound- movement of energy through substances in
longitudinal waves
○ Electrical Energy- movement of electrons Ex. Lightning
Nuclear Energy
Nuclear energy = energy that holds together protons and neutrons
within the nucleus of an atom. We
harness this energy by converting it to
thermal energy, which can then be used
to generate electricity
Nuclear power has expanded 15-fold
since 1970.
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Energy comes from the radioactive element uranium bc it’s
radioactive. half-life, the amount of time it takes for one-half
of the atoms to give off radiation and decay.
● Nuclear fission = energy is released by splitting apart uranium
nuclei by bombarding them with neutrons
● Its waste is dangerously radioactive. and Consequences of
accidents can be catastrophic.
● Examples: Three Mile Island and Chernobyl
Fission
Fusion
Takes little energy to split two
atoms in a fission reaction.
Extremely high energy is required
to bring two or more protons
close enough that nuclear forces
overcome their electrostatic
repulsion.
The energy released by fission is
a million times greater than that
released in chemical reactions,
but lower than the energy
released by nuclear fusion.
The energy released by fusion is
three to four times greater than
the energy released by fission.
One class of nuclear weapon is a
fission bomb, also known as an
atomic bomb or atom bomb.
One class of nuclear weapon is
the hydrogen bomb, which uses a
fission reaction to "trigger" a
fusion reaction.