Download Environmental Chemistry

Environmental
Chemistry
Environmental Chemistry…in
Hollywood…
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http://www.youtube.com/watch?v=Pvpzcapm
TUI
http://www.youtube.com/watch?v=5Jdk3riKK
wo
What does this have to do with me???
Hmmmm….
Big Ideas for Unit C
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Investigate the role of beneficial and harmful
substances in the environment.
Identify processes of measuring the quantity of
substances in the environment.
Identify processes for monitoring air and water
quality.
Analyze the distribution of of potentially
harmful substances within an environment.
GO C1
Investigate and describe, in general terms, the role of different substances in the environment in
supporting or harming humans and other living things.
http://www.chem4kids.com/files/art/etcetera_envirochem1_240.jpg
1.1 Chemicals in the Environment
Guided Question
How do harmful substances enter and interfere with
an ecosystem through the water, carbon, and
nitrogen cycles?
Environmental Cycles
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Essential nutrients are naturally recycled in our
environment.
The Earth runs into pollution problems when
harmful substances interfere with these cycles or
enter an ecosystem through these cycles.
Water cycle
http://pmm.nasa.gov/education/sites/default/files/article_images/Water-Cycle-Art2A.png
http://www.youtube.com/watch?v=oaDkph9yQBs
The Carbon Cycle
http://www.ucar.edu/learn/images/carboncy.gif
http://www.youtube.com/watch?v=mldBE9Ee3zY
Nitrogen Cycle
http://www.youtube.com/watch?v=tSzLQojOItg
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Most organisms are unable to use nitrogen
(N2) unless it is joined to other elements.
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Nitrogen-Fixation is the process of changing
free nitrogen so that the atoms can combine
with other elements to form compounds that
organisms can use (NH3)
Nitrogen-fixing bacteria found in the plant
nodes or nodules of legumes such as peas,
beans, clover and alfalfa, convert nitrogen
from the air into nitrates.
Lightning, too, converts nitrogen gas into
nitrates.
Human Activities
Agricultural activities
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A fertilizer is a substance that enriches
the soil so that plants will grow better.
Fertilizers contain three elements:
nitrogen, phosphorous, and potassium.
Too much fertilizer can damage
organisms (burn) in the soil and even
damage crops. If too much fertilizer
gets into ponds, streams, etc. it can
damage ecosystems.
Healthy coral
Dead Coral –
Fertilizers??
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The three numbers indicate the percentage
of each element contained in the fertilizer
In this fertilizer there would be 16%
Nitrogen, 0 % Phosphorus and 8% Potassium
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Pesticides are
chemicals used to
kill or control pests.
A pest is an
organism that harms
people, crops, or
structures.
Some pesticides are
non-selective – they
kill both pest and
non-pest species.
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Some pests become
resistant to
pesticides so new
and stronger
pesticides must be
developed.
Pesticides
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Pesticides are grouped according to the
pest that they control or kill.
Herbicides kill or control weeds
 Insecticides kill or control insects
 Fungicides kill fungi
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DDT
DDT was a popular
insecticide for mosquitoes
until it was found to
weaken the shells of
bird’s eggs, causing rapid
decline of bird
populations
Solid wastes
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Solid waste includes the solid garbage that is
collected form households, industrial plants,
commercial buildings, institutions etc.
The safest way to dispose of solid waste is to
reuse or recycle it
Waste that can’t be reused or recycled is
placed in landfill sites
 Sanitary landfills use plastic liners and
compacted clay to prevent water from
moving through the solid waste and bringing
chemicals into the soil and ground water
Wastewater
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The major pollutants affect the water
by depleting valuable oxygen in the water
and at the same time adding poisons to
the water.
When oxygen is present, bacteria will
decompose raw sewage. However, where
there is an overload of sewage, so much
oxygen is used up that fish and other
aquatic life will die.
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Waste H2O containing dissolved and
undissolved materials is called sewage and
must be treated.
In cities sewage moves to a sewage treatment
plant or a septic tank in rural areas
During heavy rainstorms, overflow wastewater
is sometimes carried directly to a body of
water without treatment by storm sewers.
Sewage
Septic tank
Bacteria break down organic materials
Sewage treatment plant
Treats waste form homes, businesses etc
After treatment effluent is released
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The treatment process involves three
stages:
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Physical: much of the larger material is
filtered out by screens.
Biological: organic sewage material is
decomposed by the action of bacteria.
Chemical: chemicals are added to remove
inorganic phosphates and nitrates.
Fuel combustion
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Fossil fuels are non-renewable resources and
are formed from dead plants and animals.
When fossil fuels are burned, they produce CO2
and water vapour.
Combustion of fuels
Hydrocarbon + oxygen carbon dioxide + water + ENERGY
(Any fuel)
**Could be methane, propane, gasoline - doesn’t matter
Industrial Processes
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Natural gas is processed to separate its
components for different uses.
When hydrogen sulfide is found in
natural gas it is referred to as sour gas.
H2S(g) must be removed because it is
poisonous. This results in sweet gas.
With removal of H2S(g) , SO2 and S are
released and need to be monitored.