2. At the end of this session the students
should be able to:-
1. Give a descriptive definition of the
term air.
2. List the composition of Air and their
percentages.
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3. 3. Describe the remaining constant of Air and their
composition.
4. Explain the importance of air to man.
5.Explain the disadvantage of air to man
5. Outline the importance of air to Pharmacy.
6. Explain the disadvantages of Air as a medium.
7. Describe the advantages/disadvantages of Air
in Pharmacy.
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4. Is a mixture of gases and varying
quantities of organic and inorganic
matters, water, vapour, rare gases
and millions of microorganisms
some of which are responsible for
the spread of various diseases to
man.
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5. The gases are well mixed together
but not chemically combined. By
this we mean that various gases
have not joined together to form a
new gas, but have remained in their
original form and have retained
their properties and identities.
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6. Approximately Air has the following
compositions:-
◦ Oxygen……………………… 20.96%
◦ Carbon dioxide…………….. 0.03 – 0.04%
◦ Nitrogen…………………….. 79%
◦ Rare gases…………………... 1%
◦ Water vapour. This varies with temperature,
and also with the location.
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8. Why these compositions remain constant?
These compositions remain constant owing to the
fact that the plants by virtual of their
chlorophyll contents take up CO2(carbon
dioxide) from the air and give out oxygen (O2),
and also the formation of carbon dioxide which
is always going as a result of existence of
animal life, combustion etc.
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9. The nitrogen cycle is the process by which
nitrogen is converted between its various
chemical forms. This transformation can be
carried out via both biological and non-
biological processes. Important processes in
the nitrogen cycle include fixation,
mineralization, nitrification, and
denitrification. The majority of
Earth's atmosphere (approximately 78%) is
nitrogen, making it the largest pool of
nitrogen.
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10. Conversion of N2
The conversion of nitrogen (N2) from the
atmosphere into a form readily available to plants
and hence to animals and humans is an important
step in the nitrogen cycle, which distributes the
supply of this essential nutrient. There are four
ways to convert N2 (atmospheric nitrogen gas) into
more chemically reactive forms:
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11. Assimilation
Plants get nitrogen from the soil, by absorption of their roots
in the form of either nitrate ions or ammonium ions. All
nitrogen obtained by animals can be traced back to the
eating of plants at some stage of the food chain.
Plants can absorb nitrate or ammonium ions from the soil via
their root hairs. If nitrate is absorbed, it is first reduced to
nitrite ions and then ammonium ions for incorporation into
amino acids, nucleic acids, and chlorophyll
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12. Ammonification
When a plant or animal dies, or an animal expels waste, the
initial form of nitrogen is organic. Bacteria, or fungi in some
cases, convert the organic nitrogen within the remains back
into ammonium (NH4
+
), a process called ammonification or
mineralization.
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13. Nitrification
The conversion of ammonium to nitrate is performed primarily
by soil-living bacteria and other nitrifying bacteria. The
primary stage of nitrification, the oxidation of ammonium
(NH4
+
) is performed by bacteria such as the Nitrosomonas
species, which converts ammonia to nitrites (NO2
-
). Other
bacterial species, such as the Nitrobacter, are responsible for
the oxidation of the nitrites into nitrates (NO3
-
).[2]
It is important
for the nitrites to be converted to nitrates because
accumulated nitrites are toxic to plant life.
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14. Denitrification
Denitrification is the reduction of nitrates back
into the largely inert nitrogen gas (N2),
completing the nitrogen cycle. This process is
performed by bacterial species such as
Pseudomonas and Clostridium in anaerobic
conditions
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18. The carbon cycle is the process through which
carbon is cycled through the air, ground, plants,
animals, and fossil fuels. Large amounts of carbon
exist in the atmosphere as carbon dioxide (CO2).
Carbon dioxide is cycled by green plants during the
process known as photosynthesis to make organic
molecules (glucose, which is food).
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19. This is where the nourishment of every
heterotrophic organism comes from.
Animals do the opposite of plants--they
release carbon dioxide back into the air
as a waste product from respiration.
(Note: Plants also undergo respiration
to make food, but the majority of the
carbon dioxide in the air comes from
heterotrophic respiration).
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20. Decomposers, when they break
down dead organic matter,
release carbon dioxide into the
air also. Decomposers are
essential because without them,
all of the carbon on the planet
would eventually become locked
up in dead carcasses and other
trash.
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21. Decay permits carbon to be released back into the
food web. Carbon is also stored in fossil fuels, such
as coal, petroleum, and natural gas. When these are
burned, carbon dioxide is also released back into
the air. Volcanoes and fires also release large
amounts of CO2 into the atmosphere. Carbon
dioxide can dissolve in water, where some of it is
later returned back into the atmosphere. The rest
can be taken to form calcium carbonate, which
builds up shells, rocks, and skeletons of protozoans
and coral.
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24. Man is totally dependant of air for survival.
The two (2) main function of air are:-
1. Interchange of gases in the process of
respiration
2. Regulation of body temperature
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25. As a medium, air is a mode of
disease transmission e.g.
tuberculosis, chicken pox,
measles etc
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26. Importance of air to Pharmacy:
In relation to pharmacy, air is important
in that most of the operations we
undertake in pharmacy are conducted in
the presence of air e.g. (in the
preparation of extemporaneous and
sterile preparations, dispensing etc).
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27. Hot air can be used to some
advantage to a pharmacy to
sterilize equipment and
medicament, which cannot with
stand moist air.
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28. As a medium, air is bound to
contain various substance their
in which are liable to
contaminate the preparations.
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29. On the other hand, air will interfere with
efficient sterilization by an autoclave i.e. a
machine used moist air (steam)
sterilization. Pure saturated steam has a
definite temperature at a particular
pressure. But a mixture of air and stem at
the same pressure has a low temperature
because of the air present.
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30. Also some pharmaceuticals undergo
deterioration when packed in containers
which allow air and in such products
therefore are packed in air – tight
containers or are packed with antioxidants
e.g. Injectable and infusions.
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