Combustion Reactions Video Lecture - Class 10

in this video gonna learn about
combustion reactions there are two types
of combustion reactions the first is a
complete combustion reaction and then
the second is an incomplete combustion
reaction so in both types we're gonna
have essentially the same reactants
we're gonna have a hydrocarbon and then
that is going to react with oxygen gas
which is o2 the difference between these
two types complete and incomplete is
going to be in the products so let's
start with hydrocarbons what are those
well hydrocarbons are compounds that are
composed of just two atoms carbon atoms
and hydrogen atoms so that'd be like
propane propane is a fuel that is
commonly used in barbecues and grills
and things like that and this is what
propane looks like it's a hydrocarbon
because it's made up of just hydrogen
and carbon hydrocarbons are combustible
and that means they're gonna burn in
oxygen and there's other compounds that
will undergo combustion other than
hydrocarbons but we're gonna keep things
simple and just look at hydrocarbons
however we are gonna include with these
hydrocarbon compounds some other
compounds are very similar that contain
carbon hydrogen and oxygen like ethanol
ethanol is a fuel additive to gasoline
and ethanol as the formula c2h5oh so
there's oxygen here in the ethanol but
ethanol is going to combust just like
another hydrocarbon we're gonna end up
with the same stuff so no matter what
the hydrocarbon is we can have any type
of hydro car always gonna produce the
same stuff so in a complete combustion
reaction this is kind of like the simple
general formula that a combustion
reaction is going to take on well take
the hydrocarbon it'll react with oxygen
gas and we'll end up with the same thing
every single time carbon dioxide and
water that's it so no matter what this
hydrocarbon is we're always going to
produce carbon dioxide and water so an
example of this would be methane ch4
we are reacting with oxygen gas which is
always o2 and we'll end up with co2 and
h2o we always just have to go back and
balance these so that's kind of the
trick to them is coming up with the
correct balancing so in this case we
need to put a 2 right there in front of
the water and a 2 right there in front
of the o2 to get everything to balance
out we can try another example here this
time let's see how ethanol wood combusts
oh here's ethanol reacting with o2 and
of course it's gonna produce co2 and h2o
this is a complete combustion reaction
then we just have to go ahead and bounce
it so put a 3 a 2 and then a 3 to get
everything to balance out so there is
our complete combustion reaction we just
made carbon dioxide and water so what
about incomplete incomplete means that
the reaction wasn't completely efficient
so we've made some impurities along with
the carbon dioxide and water and
generally those imperial days are gonna
be soot and that suit is just made up of
carbon atoms and carbon monoxide which
is co so now these are in addition to in
addition to the carbon monoxide in the
water now some people when they write
incomplete combustion reactions they
include both the carbon monoxide and the
carbon along with the co2 and h2o but
some people just don't worry about the C
part they just say well it's incomplete
we're gonna just add carbon monoxide to
the product side so again these would
both be on the product side so let's
look at what that looks like
by taking methane here and doing it in
complete combustion so still gonna make
co2 and h2o but then we're also going to
produce carbon monoxide and so this is
going to create a little bit of a
challenge in balancing so be patient
with these ones as
balance them in this one in this case
I'm gonna put a four front and then a
seven here and then a 2 and then and
eight and then a two and that's gonna be
balanced so they do take a bit of
patience to get those to balance and if
you want to review balancing just go
ahead and watch the lesson again on
balancing chemical equations so that's
one type of way that people write in
complete reaction the other type is that
they're gonna include carbon as well and
so you can see the difference here is I
decided that carbon to represent that so
that's produced so again balanced things
a bit of a challenge for this one we
would put a 4 and a 6 there and then an
8 front of the water and a 2 front of
the carbon monoxide and we get
everything to balance out so that is
complete and incomplete combustion
reactions