Oxygen is most commonly seen as gas but under certain conditions we can see it
as liquid.
It is actually the temperature and the pressure that determines whether
something will exist as a gas solid or liquid.
In the atmospheric pressure that we live in oxygen is a gas but if we increase
the pressure enough or lower the temperature enough we can put it back
into a liquid or even a solid.
This can be pretty easily visualized in a graph which is known as a phase
diagram.
At home putting something under extreme pressure is kind of hard and dangerous
but cooling down as much easier and safer.
The boiling point of liquid oxygen is slightly higher than liquid nitrogen
so what we're going to do is we're going to use liquid nitrogen to condense
oxygen gas.
So for this experiment we're going to need some liquid nitrogen and we're also
going to have to make an oxygen gas generator.
I actually cover this in a previous video and it goes into more details so
provide a link below in the description.
Well just be playing with the liquid oxygen and testing out some of its
properties it does have practical applications.
I won't really be covering its uses but I thought one interesting one was as a
liquid oxidizer for spacecraft.
Anyway that's enough of an intro and let's get to making some.
So this is my oxygen generator set up and it looks a little bit complicated
but it's actually quite simple.
The addition funnel above is filled with three percent hydrogen peroxide and the
three next round bottom flask has some manganese dioxide in it.
The manganese dioxide acts as a catalyst and when the hydrogen peroxide touches
it it breaks into water and oxygen.
The oxygen is pushed out of the neck on the right and down a tube containing
drying agent.
In my case I used calcium chloride and it's important to drive the oxygen
because it will be carrying quite a bit of water with it.
The oxygen is now dry and it passes through a little bit of hosing which
leads into a test tube.
This test two will be put into some liquid nitrogen so the oxygen condenses.
So now liquid nitrogen is transferred from the large doer into a vacuum
thermos. The liquid nitrogen will initially boil a lot as it cools down
the inside of the thermos.
The vacuum thermos is then placed below the test tube and it can now be lowered
inside.
The moment it touches the liquid nitrogen it starts to boil rapidly and
this can be limited if it's lower down slowly.
I was a little bit impatient so I lowered in quite quickly and you can see
a lot of splashing occurs.
So now we're ready and we can start generating our oxygen.
The hydrogen peroxide is dripped in and you can immediately see that our
reactions is occurring.
It's important to use a lower concentration of hydrogen peroxide so
that your reaction flask doesn't get too hot.
Keeping it cool isn't really a matter of safety it just means the hotter it gets
the more water it's going to pass over.
...test tube side it doesn't really seem like much is happening, but there is
oxygen condensing inside.
After is running for a while you can see a pretty decent amount of water starts
to come over.
However the drawing to works pretty well and not much the water makes it through.
So when we think we have enough we can take it out of the liquid nitrogen and
we can see that there is quite a bit of liquid oxygen.
However the tube is so cold that it quickly ice is over.
Using a paper towel I wipe off the ice and you can see the nice pale blue color
of the liquid oxygen.
First experiment we pour some liquid oxygen into a beaker and we lower some
pre ignited steel wool into it.
As an added bonus my friend offers an excellent commentary to the reaction.
You just broke your beaker.
If we use the finer grade of steel wool the reaction probably would have
occurred quicker and smoother.
Because we used very thick grade of steel wool, it left a lot of large molten
globules on the bottom.
These globs of iron oxide or rust were actually so hot they melted into the
glass.
And as my friend pointed out the beaker broke through the tremendous amount of
heat that was producing the reaction.
From the large test tube I transfer some of the liquid oxygen into a smaller tube.
As it cools down the test tube it boils lot but eventually it settles down.
And then for the second classic experiment with liquid oxygen is we drop
a flaming match into it.
When the match is near the opening of the tube you can see it burns brighter
due to the oxygen.
When this match is dropped in it will also burn until it disappears.
This can be done over and over again until there's no liquid oxygen remaining.
When the test is removed and all the liquid oxygen is gone
you can see that the only thing remaining is a little bit of each of the
match heads.
The wooden part of the match is oxidized all the way to CO2 and escapes as gas
but this part when its oxidized is not a gas and remains in the tube.
And
for the final demonstration - will show the paramagnetic properties of oxygen.
Oxygen molecules are always paramagnetic but when it's in its gas form the
molecules are moving way too quickly to really be affected by magnets.
Paramagnetic simply means that it's attracted to a magnetic field but once
it leaves its no longer magnetize like let's say iron can be.
When we place a magnet next of liquid oxygen and pull up
we can actually see a small global liquid oxygen going with it.
And when we pull the wagon away the drop falls back down.
So that's really all I have to show for liquid oxygen and just for good measure
I'll drop one last match into what remains.
So remember if you're interested in seeing something in a future video just
drop a suggestion in the comments below.
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