YEAR
11 CHEMESTRY RESEARCH ASSIGNMENT
Chemistry
in Everyday Life
TOPIC:- “Applications of Chemistry in Health and
Hygiene”
Throughout the centuries,
there have been many benefits brought by chemistry to our daily living. Two significant contributions made by
chemistry towards our lifestyle is the protection of our health and
hygiene. The purification our water by
process of chlorination, dental cleanliness from toothpaste, sterilisation, the
control and the cure of disease are all a part of daily living discovered and
created by chemistry. These discoveries
make up a major component for the protection of our health and hygiene and are
vital for the future existence of mankind.
The ideal water for humans
is hard water. Hard water is healthy as
it consists of calcium, Ca2+, and magnesium, Mg2+, ions.
Ca2+ are needed in the formation of bones and are important in the
clotting of the blood and regulating the heart beat. Mg2+ are needed
for making protein and for passing impulses along nerve cells. The chlorination of water for drinking makes
the water safe because it rids it from the diseases which can be transmitted
through it. However, ideal water isn’t
necessarily pure water. Pure water is
expensive to produce, is tasteless and lacks in magnesium ions. Magnesium ions reduce the incidence of the
hardening of arteries and therefore is used in the protection against heart
disease. The gas chlorine, Cl2,
is most useful to purify water. Chlorine
kills viruses and bacteria because it reacts with water to produce hypochlorous
acid.
Cl2 + H2O HCL +
HCLO
hypochlorous
acid
One aim of chemistry is to maintain dental cleanliness. Bacterial infection of the tooth structure is
called dental caries. The bacteria
convert the sugar in our diet, particularly sucrose, C12H22O11,
to a glue to stick themselves to the tooth surface. Acids such as acetic, propanoic and lactic are also produced. These acids cause the calcium phosphate in
the tooth enamel to dissolve. The
reaction is:
Ca3(PO4)2 + 4H+ Ca(H2PO4)2
soluble
calcium
dihydrogen
phosphate
When the enamel weakens, the
organisms can then invade the tooth which may eventually be destroyed. The fluoridation of water supplies is
beneficial as the hydroxide ions in the tooth enamel are replaced by fluoride
ions. It has been suggested that the
fluoride ions slow down the growth of bacteria.
The aim of toothpaste is to clean and polish the teeth. It basically consists of a mild abrasive,
usually powdered calcium carbonate and a small amount of soap. These solids are suspended in a liquid,
usually glycerol, and dyes and flavourings are added. The addition of fluoride ions, F-,
from sodium fluoride, NaF, is beneficial for children as the fluoride ions will
help form a stronger enamel while their teeth grow.
Sterilisation is the
destruction of bacteria and is an essential part in the fight against
disease. Heating is used to kill
bacteria and the cooking of food is an everyday example. Milk is partially sterilised by heating it to
about 800C and maintaining the temperature for about 16
seconds. This process is called
pasteurisation and ensures that all potential harmful bacteria are destroyed
within the milk. Chemists have produced
many bacteria killing chemicals and the use of these has saved many lives. The first of these chemicals was a dilute
solution of carbolic acid, C6H5OH. In 1985, a surgeon named Joseph Lister began
sterilising surgical wounds with this solution.
The number of deaths in his wards decreased because of this
practice. Two main solutions used to
kill bacteria in the home are antiseptics and disinfectants. Disinfectants are stronger than antiseptics
and are too harsh, irritant or toxic to be used on the skin. It is usually used to clean or sterilise
objects such as surgical instruments.
Antiseptics are used on the skin, either before surgery or on cuts and
bruises, and prevents sepsis which is the destruction of the tissues by
bacteria.
One aim of medicine is to
control disease with the use of chemicals.
Chemicals, or drugs, are made from natural causes such as plant or
animal extract, or are made in the laboratory.
The most successful synthetic drug in the world today is called acetyl
salicylic acid, or more known as aspirin.
It is made from salicylic acid, a disinfectant, and acetic acid.
Aspirin is anti-inflammatory, meaning it reduces swelling, redness,
relieves arthritis and is effective against stroke. However, if used too much side effects such
as internal bleeding of the stomach occur. Aspirin is also known as an
analgesic as it is a pain killer. Three
types of pain killers are strong analgesics, local anesthetics, and
sedatives. Strong analgesics are complex
nitrogen compounds isolated from opium such as morphine (C17H19NO3.H2O). Local anesthetics reduce the sensitivity of
nerve fibers to reduce pain such as cocaine (C17H21NO4). Sedatives are drugs which reduce tension and
anxiety such as codeine (C18H19NO3.H2O).
Another aim of medicine is to cure disease. The use of chemical agents to destroy
infectious organisms, or diseases, without destroying the host is called
chemotherapy. Before 1900, only three
chemical remedies were known: chinchona
bark for malaria, ipecacaunha for dysentery, and mercury for syphilis. Very significant types of drugs related to
chemotherapy are drugs containing sulfur, or sulfa drugs. Sulfa drugs are dyes that are specifically
lethal to harmful microorganisms. Protonsil was the first sulfa drug. It breaks down in the body to sulfanilamide,
which is effective in destroying streptococci.
Bacteria need para-aminobenzoic acid to make a vitamin called folic
acid to grow, and as the structure of sulfanilamide is similar to
para-aminobenzoic acid, the bacteria can’t distinguish between the two
chemicals. The bacteria take in the
sulfa drug instead of the para-aminobenzoic acid and die. Luckily, humans don’t need para-aminobenzoic
acid to make folic acid so they are unaffected by sulfa drugs. Compounds related to sulfanilamide were
tested: sulfapyridine was effective
against pneumonia and sulfathiazole saved the lives of many wounded soldiers
during World War II.
There are many contributions
made by chemistry that deal with our lives.
The simple health and hygiene of a human, in particular, consisted of
many hours of hard and dedicated work and research by chemists. The purification of our water by
chlorination, dental cleanliness by toothpaste, the sterilisation of a cut, the
control of disease by aspirin, and the cure of disease by chemotherapy have all
contributed to our livelihood and our health.
Whenever we drink tap water, brush our teeth, dress a wound, have an
aspirin for our headache or drink medicine we are using these contributions
made by chemistry. Without these
contributions, we would not be living in the clean and healthy lifestyle that
we live in today.
BIBLIOGRAPHY
Merlin Internet
http.//www.amcal.com
World Book Encyclopedia Volume 13 M pp.299-306
George W. Beadle
Chemistry 2000 Chapter 22 – Health & Hygiene pp.367-378
R.J. Stanley
Encarta ’95 Electronic
Encyclopedia
Medicine
C.D. O’Malley
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