Transcript E-42 Environmental Chemistry

E-42 Environmental
Chemistry
About this “E”…
In the following slides, you will learn about how
chemical elements and compounds are involved in the
following environmental issues:
On the Ground:
1. Heavy Metal Poisoning
2. Radon (Rn)
In the Air:
1.
2.
3.
4.
Air Pollution/Smog
Acid Rain
The Greenhouse Effect/Global Warming
Ground Level Ozone/Ozone Hole
Solutions:
1. Recycling
2. Alternative Energy
Heavy Metal Poisoning
What Are Heavy Metals? … Heavy metals are toxic metals found in the
transition metals section of the Periodic Table (See the examples below.).
The Effects of Heavy Metals on People … general body toxicity, metabolic
problems, learning and memory problems, permanent brain damage, and, even,
death!!!
Mad as a Hatter? … In Alice and Wonderland the Mad Hatter was based on
the Victorian hat makers who went “crazy” from long term exposure to the
mercury used to soften beaver fur for hats.
How You Can Protect Your Family From Heavy Metal Poisoning … Check
your home for lead based paint and professionally remove or repair cracked
paint and paint chips; Do not purchase or use mercury thermometers or other
mercury instruments; and gather all items containing heavy metals and take
them to a hazardous waste facility.
Lead (Pb)
Examples of Heavy Metals:
 Lead (Pb)
 Cadmium (Cd)
 Mercury (Hg)
 Chromium (Cr)
Mercury (Hg)
Radon (Rn)
Where its found … in the granite bedrock under much of the United
States.
The Effects of Radon on People … radon combines with atmospheric
dust and then sticks to lung tissue where it is believed to play a
significant role in causing lung cancers.
An Invisible Killer … radon is a colorless, odorless gas.
How You Can Protect Your Family From Radon Poisoning? … Have
your home tested for radon. If it is discovered, install the appropriate
ventilation systems.
The Chemical Composition
of the Atmosphere
Most Abundant Elements



Nitrogen (N)
Oxygen (O2)
Argon (Ar)
Most Abundant Compounds



(More than one element)
Carbon dioxide (CO2)
Water Vapor (H2O)
Important note: The composition of air is usually given for dry air because
water vapor content in air varies greatly from place to place and by season
(Air can range from less than 1% to more than 4% water vapor.).
Air Pollution … AKA Smog
 Air pollution – harmful substances that get into the air (ex. carbon
monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides
(NO2, N2O4), hydrocarbons(CnH2n+2), lead (Pb), and mercury (Hg)). The burning
of fossil fuels and automobile exhaust are major sources of air pollution. Air
pollution can cause asthma, allergies, lung disease, and even death in humans!
Temperature inversion – a dangerous condition in which a layer of colder,
polluted air is trapped below a layer of warm air and cannot disperse. This
happens in California where polluted Pacific air becomes trapped near the
surface causing smog (NO2).
Rain Gone Bad … Acid Rain!!!
All rain is somewhat naturally acidic, but when chemicals from car
and factory exhaust (CO, CO2, NO, NO2, N2O4 SO, SO2) combine
with rainwater (H2O), they can produce HIGHLY acidic rains
(H2CO3) that damage buildings and monuments and kill plants and
fish (ex. H O + CO → H CO ).
Layers of the Atmosphere 1
Did you know…
99% of the mass of
the atmosphere is
located within 32 km
(20 miles) of the
Earth’s surface!!!
Mount Everest,
the highest elevation
above sea level, is
only about 8.8 km
high, keeping it in
the bottom layer of
the atmosphere.
The Earth's atmosphere is composed of several layers:
We live in the Troposphere where Global Warming/The Greenhouse Effect
takes place and almost all weather occurs (ex. wind, clouds, fog, rain, hail,
sleet, snow and storms).
Above the Troposphere is the Stratosphere, which contains the Ozone Layer,
which blocks out harmful UV rays.
Commercial airliners (ex. a 747) usually fly in the troposphere, whereas
supersonic jet airliners (ex. the Concorde) fly in the lower stratosphere.
Layers of the Atmosphere 2
Thermosphere
Lower region called ionosphere.
Upper region called exosphere.
Nitrogen and oxygen atoms absorb
deadly gamma and X rays here, explaining
the unexpected increase in temperature.
Mesosphere
Coldest layer of the atmosphere.
Stratosphere
The Ozone Layer absorbs harmful UV
Rays here, explaining another unexpected
increase in temperature.
Troposphere
Greenhouse Gases trap infrared rays
(heat) in here causing Global Warming.
All weather change occurs here.
 Temperature within this layer
decreases as altitude increases because
there is an increase in distance from the
warming effect of sunlight absorbed by
the Earth’s surface.

The Electromagnetic Spectrum
Types of Waves in the
Electromagnetic
Spectrum (from
highest to lowest
energy):
1. Gamma Rays
2. X Rays
3. Ultraviolet
4. Visible light
5. Infrared
6. Microwaves
7. Radio waves
8. TV waves
Important note: The shorter the wavelength, the more energetic the
wavelength is and the more harmful the wave is to human tissue!!!
Infrared Radiation: Heat!
When infrared rays pass through an object,
you feel them as warmth or heat.

Infrared rays heat rocks, soil, water and other Earth materials on
the ground.
 These heated objects reradiate longer wavelengths of infrared
radiation. These longer wavelengths of radiation are then trapped by
the carbon dioxide and water vapor in the Earth’s atmosphere on
their way back up into the sky.
Outgoing Radiation and
The Greenhouse Effect

Greenhouse Effect
– the process by which visible light and shorter waves of infrared
radiation enter the Earth’s atmosphere from the Sun, strike the
Earth’s surface, are reradiated as longer wavelengths of infrared
radiation, and are then trapped by carbon dioxide (CO2) and water
(H2O) vapor in the atmosphere.
Do You like summer?
This trapping of heat causes the Earth’s surface and troposphere (the bottom
layer of the atmosphere) to be warmer than if there was no atmosphere at all.
The Greenhouse Effect: the Big Picture
The Global Warming: Many Factors
Manmade (ex. the burning of hydrocarbon fossil fuels, CnH2n+2) and natural (ex.
volcanic eruptions) releases of “Greenhouse gases” into the atmosphere may
increase temperatures on the Earth over the next century, leading to the
melting of glaciers; disruptions in weather patterns, climate zones, and
habitats; increasingly severe storms; massive coastal flooding; and crop
failures unless the Earth can compensate (by storing carbon dioxide in rocks
and seashells and by encouraging the growth of more photosynthetic
organisms).
UV Rays … Energetic and Harmful!!!
Since they have relatively short, fairly energetic wavelengths,
ultraviolet or UV rays are the harmful to humans …
Ozone (O3) in the stratosphere absorbs most UV waves before they
reach the Earth’s surface.
Ozone (O3): Important Substance
in the Atmosphere
Ozone (O3) is a form of
oxygen found in the
stratosphere.
Before Earth had an ozone layer,
all life lived under the oceans …
NONE could live above them!
Ozone absorbs harmful
ultraviolet radiation (UV rays)
coming from the sun.
Ultraviolet radiation can cause
severe burns, cancers, mutations,
and even death!
Ozone can be destroyed by:
CFC propellants in old aerosol
spray cans, Freon coolant from
refrigerants in old refrigerators
and air conditioners, and the
burning of supersonic aircraft
fuel.
Ozone: a Little Chemistry
Ozone is created when ultraviolet radiation (UV rays) from
the Sun strikes and splits oxygen molecules (O2) to atomic
oxygen (O).
The atomic oxygen (O) quickly combines with further
oxygen molecules to form ozone (O3):
O2 + light
->
O + O2 ->
O + O
(1)
O3
(2)
CFCs are chemicals that interfere in this ozone making process.
It should be noted that ground level ozone, which is produced
by hydrocarbons that react with sunlight, is a pollutant itself.
Ground level ozone causes SERIOUS lung irritation!!!
Recycling

Biodegradable – things that can be broken down quickly in
the natural environment (ex. egg shells, apple and potato
peels, and string.)
 Nonbiodegradable – things that remain in the environment
for long periods of time unchanged (ex. plastic, glass, and
steel.)
 Recycling – saving and reusing materials (See examples
below.).
Materials that can
be recycled:
Paper (organic compound)
Cardboard (organic compound)
Plastics (organic compounds)
Glass (based on SiO2)
Aluminum (Al)
Steel (an iron alloy)
All of the following can be recycled…
Alternative Energy
Running Out of Gas? … Most experts agree that we will run out of
fossil fuels in our lifetime, even if we don’t, alternative energy would
free us from the rising cost of petroleum based fuels and the politics
that accompany them…
Sources of Alternative Energy:
Wind Power
 Water Power
Hydrothermal Power
 Solar Power


More On Wind Power …
Here!
A Source We Can Use
Wind power is one of several potential sources of cleaner,
alternative energy.
At our latitude (approximately 40°N), wind power might be able to
supply a substantial fraction of the energy we need to generate
electricity.
The Equator and 30 latitude contain the areas called the doldrums
and the horse latitudes which contain unpredictable winds. As a
result, wind turbines would not be a reliable alternate energy source
for these areas.
Mid American Energy is
now collecting money to
create wind farms to
meet OUR energy
needs here in the
QCA!!!
The End!