Video: Oxidation Reduction Reactions Video Lecture - Class 10

in this first video of our two-part
series on oxidation reduction reactions
we are going to learn about oxygen
exchange in oxidation reduction
reactions in a chemical reaction
oxidation is oxygen gain and reduction
is oxygen loss first let's look at
oxidation a good example of oxidation is
a combustion reaction hydrogen is a
clean fuel that works by combination
reaction with oxygen energy is released
as bonds are formed and this energy can
be used to power cars or appliances
oxygen also combines with metals when
oxygen reacts with iron the iron is
readily oxidized do you know the common
name for fe2o3 maybe try thinking about
what happens to iron metal after it is
exposed to air for a long time you
probably got it
fe2o3 is rust this is why things made of
iron are often coated with other metals
such as zinc in a process known as
galvanization of course zinc can still
react with oxygen to make the zinc oxide
in fact it reacts so quickly that the
iron galvanized with zinc cannot oxidize
because it is coated with a protective
layer of zinc oxide you can make this
reaction go even faster by applying heat
the heat provides some of the energy
required to break bonds before new bonds
can form the activation energy
hemoglobin in blood carries oxygen
around the body by oxygen exchange
reactions for iron two plus ions sit in
the middle of a pore fire in ring when
oxygen binds the iron two-plus
reversibly oxidizes the negatively
charged oxygen is called a superoxide
when it gets to where it is needed in
the body it is released and the iron is
reduced back to iron two-plus now let's
look at reduction
remember reduction is oxygen loss some
oxides when heated release oxygen and
are reduced back in the 17th century
people believe that heating a substance
would always yield its pure elements and
sure pure oxygen was indeed first
produced by reducing mercury oxide but
what wasn't known at the time was a
heating could cause either reduction or
oxidation it is very important that we
are able to make metal oxides lose
oxygen as pure metals that result from
these processes have unique properties
that are useful for industry as an
example take a look into the blast
furnace in here we can use coke to
reduce iron or iron oxide to iron metal
don't forget the coke used in a blast
furnace is carbon coke like coal not a
fizzy drink usually the furnace is not
hot enough for the coke to react
directly with the iron oxide coke reacts
with oxygen in the air to form carbon
monoxide is this an oxidation or a
reduction pause the video for a moment
to work it out oxygen is gained by
carbon to form carbon monoxide so this
is an oxidation reaction did you get
that right so what happens to the carbon
monoxide next it reacts with the iron to
release pure iron metal simultaneous
oxidation and reduction takes place iron
loses oxygen it is reduced but kerbin
monoxide gains oxygen and forms co2 it
is oxidized we have talked about
oxidation and reduction in this video in
terms of gaining and losing oxygen using
examples from industry and nature now it
is your turn to explore other
interesting examples you can find around
you