THE CHEMICAL PHENOMENA
 A chemical phenomenon is any manifestation of the process of transformation of
matter that can be perceived by our senses.
 The term is used as a synonym of chemical reaction and of chemical change.
 Actually, the three concepts are inter-related in such a way that they are inter-
dependent.
CHEMICAL PHENOMENA CAN BE TWO TYPES:
NATURAL AND ANTHROPOGENIC.
Chemical reaction:
Process of
transformation that
depend on the chemical
properties of matter
Chemical change:
Change in structure and
properties of matter as a
consequence of the
chemical reaction
Chemical phenomenon:
Manifestation of the
chemical change
NATURAL CHEMICAL PHENOMENA
NATURAL CHEMICAL PHENOMENA
 Life in the planet is a dynamic process in which a myriad of chemical reactions
that sustain life and maintain the natural balance between the living beings, take
place constantly.
 Natural balance refers to the relationship between living beings with the
environment and between themselves.
 These are the so-called natural chemical phenomena, some of them so nromal
that we dont even wonder how they take place
 Ex: Cellular respiration (human and plants)
 Humans: inhale oxygen and exhale carbón monoxide (respiration)
 plants;: absorb carbón dioxide and reléase oxygen (photosynthesis)
NATURAL CHEMICAL PROCESSES – EXAMPLES
 F E R M E N TAT I O N
 Biochemical process by which an organic substance transforms into
another; ussually a simpler one, by the action of a microorganism called
ferment.
 Milk  (not refrigerated)  sour
 Alcoholic beverages from the fermentation of fruits
NATURAL CHEMICAL PROCESSES – EXAMPLES
 CORROSION
 Deterioration of a material caused by some chemical agents from its
environment
 Ex: formation of rust in ferrous materials by the action of oxygen and the
humidity of the atmosphere.
NATURAL CHEMICAL PROCESSES – EXAMPLES
 COMBUSTION
 Is the chemical reaction that is produced between
oxygen and a combustible material, accompanied by
the reléase of energy and regularly, it manifests as
incandescence or flame. Like the combustion of
gasoline, of natural gas, of Wood or paper, among
other materials, especially of an organic nature.
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 According to scientific theory, the formation of the first living organism in the
planet occured starting from a series of chemical reactions between substances
that were found in the primitive atmosphere and under the action of solar
energy; therefore, we may consider this process as the natural chemical
phenomenon by excellence.
ANTHROPOGENIC
CHEMICAL PHENOMENA
ANTHROPOGENIC CHEMICAL PHENOMENA
 Usually, the term is applied to
describe the diverse types of
contamination in the planet, as
a consequence of the actions that
human perform in the search for
attaining better and more
comfortable life conditions, which
has contributed to a very
pronounced technological advance in
the previous century, that is, they are
are contaminant chemical
phenomena.
 Their origin may be urban industrial,
agricultural and from livestock or
from maritime navigation.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F T H E AT M O S P H E R E
 Atmospheric contaminants are classified in two types: primary and secondary
 PRIMARY CONTAMINANTS
 Those emitted directly into the atmosphere by the
sources that originate them.
Among the most important are those that
emanate from processes that imply combustion
reactions in industries and vehicles with
internal combustion motors; the main ones are:
 Carbon dioxide and monoxide
 Nitrogen oxides
 Sulfur dioxide
 Hydrocarbons
The ones
emitted by
cars, trucks
,industrial
chimneys,
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F T H E AT M O S P H E R E
 Atmospheric contaminants are classified in two types: primary and secondary
 SECONDARY CONTAMINANTS
 Those that have the their origin in the atmosphere by reaction between two
or more primary contaminats, or among them, and the normal constituents of
air. These reactions are favored by extreme environmental conditions such as
elevated temperatures resulting from the heat produced in the combustion of
gasoline and other combustibles in motor vehicles.
 The oxides of nitrogen, the hydrocarbons and oxygen react among them in the
presence of ultraviolet radiation from the sun rays, generating the appearance of
oxides in the atmosphere which, in turn, provoke a series of reactions that produce
other contaminants, one of them, o z o n e , which in turn reacts with hydrocarbons,
which transform into toxic products, such as aldehydes and acetones, among others.
 Oxidants associated to a strong insolation.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F WAT E R
 Occurs by the presence of contaminating substances, whose sources can be of
urban, industrial, agricultural, livestock and maritime navigation origin.
 CONTAMINATION BY URBAN DUMPING
 From domestic activities and are of organic origin, mainly of non-degradable
material such as types of soaps and detergents, as well as edible oils.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F WAT E R
 Occurs by the presence of contaminating substances, whose sources can be of
urban, industrial, agricultural, livestock and maritime navigation origin.
 CONTAMINATION OF INDUSTRIAL ORIGIN
 Depending on the type of industry
 Examples: mercury, lead and arsenic generated by the mining and steel industry .
Chrome and inorganic solvents come from the textile industry. Paint industries
also generate paper and chemicals.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F WAT E R
 Occurs by the presence of contaminating substances,
whose sources can be of urban, industrial, agricultural,
livestock and maritime navigation origin.
 AGRICULTURAL AND LIVESTOCK INDUSTRY
CONTAMINANTS
 This type of activity generates contaminants by the
agricultural use of pesticides and fertilizers; also by
organic residues of animals and plants.
 Livestock activity contaminates by cow manure, urine
and the cleaning products used in abundance.
 The presence of nitrates in the water of the wells,
derived from human and animal excrements are a
source of microbial contamination.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F W AT E R
 Occurs by the presence of contaminating substances, whose sources can be of urban,
industrial, agricultural, livestock and maritime navigation origin.
 MARITIME NAVIGATION
 The contamination of the seas is a cause of
concern due to its grave impact on the lives
of diverse marine species. It is mainly caused
by hydrocarbons proceeding from
oil spilled by oil tankers and other means
of maritime transport.
 The damage they cause are severe since they
affect the fauna and fishing, as well as the near
coasts.
 Its effects are felt for a long time.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F T H E G R O U N D
 The ground is the superficial part of the Earth’s crust and is a nature resource
necessary for life.
 Its nature is determined by the interaction of physical, chemical and biological
factors.
 The main contaminants in the country are the agrochemicals used for
preservation of the crops, mainly fertilizers and pesticides.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F T H E G R O U N D
 The fertilizers provide nutrients to favor the development and quality of the crops.
The problem presents when quantities beyond the ground´s capacity for absorption
are applied; at that moment, they change from beneficial to contaminants, since the
excess of nitrates and phosphates which are the main components, transform the
ground in the medium through which severe problems of contamination of waters
are produced.
 Another severe problem is when this excess infiltrates from the subsoil towards
subterranean waters. When consumed by humans, this water transforms the nitrates
into nitrites by the action of some bacteria that exist in the stomach and urinary
bladder; the nitrites convert into certain compounds called nitrosamines, that affect
the stomach and liver with carcinogenic effects.
ANTHROPOGENIC CHEMICAL PHENOMENA
EXAMPLES
 C O N TA M I N AT I O N O F T H E G R O U N D
 Pesticides have always been used in agriculture to combat the great threat that
plagues signify. However, pesticides are contaminants because they affect the soil
and other species due to substances that form its chemical composition.
 Most pesticides contain organ chlorinated and organophosphate compounds, if
these are insecticides.
 In herbicides, are found derivatives of heterocyclic organic compounds and of
urea which are high toxicity substances.
 Fungicides of older use contain cooper and sulfur compounds, and currently,
organometallics are found, which are organic compounds with atoms of varied
metals.
OZONE LAYER

THE OZONE LAYER is a belt of the naturally occurring gas "ozone." It sits 9.3 to 18.6 miles (15 to 30
kilometers) above Earth, and serves as a shield from the harmful ultraviolet B (UVB) radiation emitted by the
sun.

Ozone is a highly reactive molecule that contains three oxygen atoms. It is constantly being formed and
broken down in the high atmosphere, 6.2 to 31 miles (10 to 50 kilometers) above Earth, in the region called
the stratosphere.

Today, there is widespread concern that the ozone layer is deteriorating due to the release of pollution
containing the chemicals chlorine and bromine. Such deterioration allows large amounts of ultraviolet B rays to
reach Earth, which can cause skin cancer and cataracts in humans and harm animals as well.

Extra ultraviolet B radiation reaching Earth also inhibits the reproductive cycle of phytoplankton, single-celled
organisms such as algae that make up the bottom rung of the food chain. Biologists fear that reductions in
phytoplankton populations will in turn lower the populations of other animals. Researchers also have
documented changes in the reproductive rates of young fish, shrimp, and crabs as well as frogs and salamanders
exposed to excess ultraviolet B.

Chlorofluorocarbons (CFCs), chemicals found mainly in spray aerosols heavily used by industrialized nations for
much of the past 50 years, are the primary culprits in ozone layer breakdown. When CFCs reach the upper
atmosphere, they are exposed to ultraviolet rays, which causes them to break down into substances that
include chlorine. The chlorine reacts with the oxygen atoms in ozone and rips apart the ozone molecule.

One atom of chlorine can destroy more than a hundred thousand ozone molecules, according to the the U.S.
Environmental Protection Agency.

The ozone layer above the Antarctic has been particularly impacted by pollution since the mid-1980s. This
region’s low temperatures speed up the conversion of CFCs to chlorine. In the southern spring and summer,
when the sun shines for long periods of the day, chlorine reacts with ultraviolet rays, destroying ozone on a
massive scale, up to 65 percent. This is what some people erroneously refer to as the "ozone hole." In other
regions, the ozone layer has deteriorated by about 20 percent.
MARIO MOLINA
 n 1995, Mario Molina received a Nobel prize in chemistry for
his work in atmospheric chemistry and the effect of
chlorofluorocarbons (CFCs) on the depletion of the
ozone layer. He shared the Nobel Prize with F. Sherwood
Rowland and Paul Crutzen. This was the first time a Nobel
Prize for research into the impact of man-made objects on
the environment was awarded. The discoveries led to an
international environmental treaty, which bans the
production of industrial chemicals that reduce the ozone
layer. Dr. Molina was named one of the top 20 Hispanics in
Technology, 1998.
 Today, Dr. Molina is one of the world's most knowledgeable
experts on pollution and the effects of chemical pollution on
the environment.