Uses of Dioxygen Video Lecture - NEET

In this video we are going to investigate the properties of oxygen. Oxygen has atomic number 8 and is
found in group sixteen of the periodic
table. It has the chemical symbol O.
Oxygen is of course a gas.
It has no smell, colour or taste but without it we
as humans would not be able to inhabit planet earth.
When cool to very low temperatures it will form a liquid and a solid which are both
pale blue. Oxygen makes up 21 percent of the
Earth's atmosphere. It has taken many
millions of years to make up this
composition. Today's atmosphere seems to
now have the perfect balance. You may want to
check the history of the atmosphere for
more details about this. Oxygen is used by the
human body in a process called
respiration. Take a deep breath in, hold it
for a few seconds. The air that entered your
body has now been held in the lungs. Some
of the oxygen you breathe in
has been taken into the bloodstream and
transported parts of the body where it's
needed. Respiration is taking place in
the cells of your body
Oxygen combines with glucose, building up
carbon dioxide and water. I'm releasing
energy. This enables cells to function and
our bodies to survive. As you breathe
out air now contains roughly 4% less
oxygen than when you breathed in.
This has been replaced by another gas called carbon dioxide. The oxygen in the atmosphere also affects our
lives in other ways. It reacts chemically
with a number of other materials. Oxygen
will combine with reactive metals to
form metal oxides. This is called
corrosion. Most metal oxides are useful
as they produce a hard protective layer.
Aluminium oxide for example forms a
protective layer on the surface of
aluminium. This grey coating protects
the body of the metal underneath from
further corrosion. Modern aeroplanes have
used this characteristic of aluminium as a
choice of construction material. Iron (III)
oxide is formed when iron reacts with water and
oxygen, and this is not useful. You all know iron (III) oxide more commonly as rust. It makes the metal
flaky and weak. The corrosion will eat into
the metal, which flakes off as the oxide
is built up. There are ways of protecting
iron from oxidation. Putting oil on your
bike for example. It will protect it from the rust and
keep it strong. Oxygen can be produced in
the lab by the chemical decomposition of
hydrogen peroxide. If the earth's atmosphere
consisted of 30 percent oxygen rather than 21
percent, forest fires would start with lightning and
would never go out. Life as we know it
would be impossible.