This interactive simulation in which we heat liquid water and air in a sealed container.
So we start out at 25 degrees, and we can set the initial volume of water, intros case
0.89 L, the entire container is 1 L. And we start at 25 degrees, and so what I am showing
you is after we raise the temperature to 166 degrees.
And what has happened is the liquid has expanded so now, instead of occupying 0.89 L it occupies
0.991 L. And so the gas volume has been compressed significantly.
The pressure now, is much higher because that gas volume was compressed and because the
saturation pressure of water is higher at 166.
On the right side of this simulation we are displaying the amount of oxygen and nitrogen.
So initially almost all of it is in the gas phase and a small amount is dissolved.
As we raise the pressure we increase the amount dissolved.
As we raise the temperature we decrease the amount dissolved.
We are raising both of course, as we raise the temperature in this simulation, and it
shows in this condition this relatively high pressure, a significant fraction, almost half
the oxygen, the original oxygen, is dissolved in the liquid phase.
The rest is in the gas phase and it is hard to display a gas volume with this large of
a liquid volume.
And so this mimics the procedure used, for example, when sea-life crystals are grown
from solution, where you autoclave a seal and raise to a significant temperature to
allow for the chemical reactions, the synthesis, to take place.
So let's look at the simulation to see the behavior of the system.
So here is the simulation and let's start by saying we have 85% of the container filled
with liquid water and then above it is air and water vapor and we are at 1 bar and 25
degrees.
So then what we are doing in this simulation, is we raise the temperature, we observe first
that the volume of the liquid is increasing because liquid water expands when we heat
it.
It is not a dramatic increase, up to 115 degrees, and it is increased from 85 to 90% of 1 liter.
And then on the right we show that a small fraction of the oxygen and the nitrogen are
dissolved.
That is the purple at the bottom of the bar graph.
And the green shows the amount that is in the gas phase.
So as we continue to raise the temperature, the first thing you'll notice is the pressure
now goes up rather dramatically and this is for two reasons.
One is the saturation pressure is dramatically higher at 183 degrees and two, the volume
of the gas is decreased from 0.15 liters to 0.037 liters.
So just from ideal gas laws the pressure of that gas is increased.
Now it hasn't increased as much as it would if there was not some of the gas dissolving.
So you notice the fraction dissolved is increased because the pressure is higher and Henry's
Law, as I start to get now to very high pressures and very high gas volumes, you will notice
now a significant fraction of the oxygen and nitrogen are dissolved.
And if I continue to raise the temperature, now we are at 45 bar pressure.
Very little vapor volume left, and that is part of the reason for the high pressure,
and also notice almost half, or very close to half, of the oxygen is now dissolved in
the water.
And I could slowly increase this further.
And I will do this by holding down the alt key while I move to the right.
Notice we are at 51.6 bar pressure.
Now more than half the oxygen dissolved and it looks like half of the nitrogen is dissolved.
And as I continue to increase, the most we can get to, extremely high pressures we have
very little vapor volume left and most of the gas now, the oxygen is actually dissolved.
And then as I push to high, we have set a pressure limit on the container and so then
the container would break.
So this simulation represents behavior when a liquid is in a sealed container.
It is used in some inorganic synthesis such as by synthesis and it takes into account
the ideal gas law, the saturation pressure, expansion of the pressure and solubility of
oxygen and nitrogen in water.