I'm going to make um an exciting mixture
a mix Shure which we can use to to show
a number of things the first of which is
going to be the rapid reaction of a fuel
with a source of oxygen and um we can
use the heat from that rapid combustion
reaction to excite other irons because
you know we could go and have a look at
an emission spectrometer and do all
sorts of elegant experiments like that
but this one is a really cheap and dirty
and honest way of seeing those different
colors from flame tests so here I've got
some sugar this is this the stuff I put
in my coffee in fact I went and got this
from our lovely Sue upstairs who's an
absolute darling and you can see I'm
going to put quite a charge in cuz we're
going to use maybe two or three
different experiments from this mixture
today so this is the second component of
our mixture and that's pottassium
chlorate and the reason we're using
chlorate is because it's got lots of
oxygen in it it allows me to put lots of
oxygen intimately close to to all of the
exciting bonds that I want to break
inside the sugar we need to add about
the same volume of pottassium
chlorate this isn't particularly good
practice so we shake it all up give it a
good
mix now we need to test that mixture
okay so we're going to pour a small
amount of it out on the bench onto a
heat proof
mat so what's in this mixture we got
sugar and we got chlorate ions because
they're delivering all of that nice
oxygen and the chlorate ions are
delivered with potassium okay so
realistically what we should see is a
nice luminescent flame from the burning
sugar with the color of excited
pottassium so it that should be a nice
lilac color so the emission spectrum of
the pottassium ion is lilac so let's
have a look all
right fantastic a lovely reaction all of
that energy in the sugar and all of the
carbon is being transformed into carbon
dioxide a little bit of Elemental carbon
there you know the nice soy carbon a lot
of water vapor a lot of steam and what
you saw there with all of that Steam and
that energy was the lovely lilac
commission spectrum of that pottassium
ion so we need to take some strontium
irons and in this case I've got a small
amount of strontium nitrate okay now I'm
going to take a small amount and put it
into a test tube now we take our
excitement
mixture give it a bit of a shake mix it
all up so all of those metal irons are
mixed into all that nice um source of of
carbon and
energy now all we need to do is add a
little bit of
[Applause]
energy wow what a fantastic reaction
really really energetic lots of energy
coming out lots of hot steam lots of hot
CO2 an important importantly a lovely
lovely red color from the strontium
emission fantastic so we're going to use
the same mixture of sugar and chlorate
but this time I'm going to add a small
amount of a different metal salt and
this time I'm going to use berium
nitrate
okay and again I'm going to add some of
my combustion mixture
now we're using the energy of that
combustion of the sugar to excite the
barium so that we can observe its
emission spectrum or the flame color
again pour it out onto a heat proof
mat so
again so this time again we saw the same
exciting chemical reaction we saw that
same exothermic reaction lots of CO2
lots of steam again but this time the
flame was colored green and this is the
the characteristic apple green which is
associated with barium salts so much
more exciting flame test every time we
change the metal we change the color so
this time we're going to try some copper
this is copper 2
chloride so instantly you'll see that
the copper salt is a really nice greeny
blue color so this is going to change
the the view of the chemistry straight
away now I'm being very careful to make
sure that this doesn't have too much I
suppose exposure to the atmosphere cuz I
don't want water to get into this
chemistry I want to try and keep it as
dry as possible now this time you'll be
able to see the efficiency of that nice
greeny copper salt Distributing into
that white combustion
mixture now that that was great a lovely
blue flame from that copper chloride
wasn't that really fantastic that was
brilliant so I'm going to make a mixture
now well I'm going to make a series of
mixtures
which I'm going to
place along the bench that's with copper
strontium
barium so let's see what happens if we
do all
three that copper Burns so
fast so periodic video is trick
aor trick that copper Burns so fast