Would it just turn into a pressurized container full of steam? Would the water stay water but just like, really hot?
In: 98
In nuclear reactors, the water that comes in contact with the core is radioactive. The water that converts to steam and then is condensed back into water is in a secondary loop. The primary loop is pressurized at a very high level so it cannot convert from a liquid to a gas, within the temperatures it operates at…
The boiling point of water isn’t always 100°C it depends on the pressure. This is why water boils at a lower temperature at higher elevations. And since it’s a sealed container and the water wants to expand as it’s heated, the pressure increases as you heat the water.
[Water phase change diagram](https://www.researchgate.net/publication/338142645/figure/fig2/AS:870171413602304@1584476440134/Schematic-water-phase-diagram-Below-the-critical-point-that-is-374-K-and-218-atm-the.png)
So in the red, it would be a liquid, and in the green it would be a gas. Beyond the critical point, there’s no difference between a liquid and gas, so it’s called a supercritical fluid.
You can also see that if you lower the pressure, the water will begin to spontaneously boil. If you get things just right, you’ll hit the triple point where the water is stable as a gas, liquid and solid all at the same time and can see boiling water with an ice cube floating in it
With any question of the form “what would happen if …” the answer is usually _it depends_. In this case, it depends on how much pressure the water was under when you put it in the container, how much heat you apply to the water, how strong the container is, and what the container is made from.
As the temperature of the water increases, the pressure inside the container will also increase. If the pressure gets high enough, it will eventually be strong enough to break the container. Very high temperatures may also weaken the container, making it easier for the pressure to break it.
When the container breaks, it’s likely that it will either explode or take off like a rocket. The temperature of the water at that point will probably be far above boiling; the water is only still a liquid because the container was sealed. As soon as it has somewhere to go, all that water will immediately change into a gas and rush out of the crack or hole that formed. If the container is weak enough, then when a hole forms the force of all that water vapor rushing out of it will tear the hole bigger and bigger and just tear the entire container to pieces. However, if the container is strong enough to resist that tearing, then the water vapor will still rush out that hole, but because it’s all accelerating in the same direction it will push the container the other direction, probably very very quickly.
If you want to see a fun illustration of this, I recommend looking up clips from the Mythbusters episode about water heaters.
Yes and no; depends entirely on your scale and perspective.
Let’s consult the [phase diagram of water](https://fi.m.wikipedia.org/wiki/Tiedosto:Phase_diagram_of_water.svg). From this we can see depending on the pressure water can have many forms. In near vacuum water will turn to vapour even in -50 Celsius. This curious effect is why north and south poles are actually the driest places, along with Atacama Desert, on earth.
But lets focus on your example. Let us say that we start with a container at one bar just above 0 so the water remains liquid. As we start to heat it up, the water temperature increases. Which means the molecules have more kinetic energy and they collide more with the walls of the container – this means that the pressure increases. It is important to understand what *heat* actually is, it is movement in a defined volume. When materials transfer heat between each other they actually collide and energy is transferred. Same amount of movement – as in energy – compressed in to smaller space means that things get hotter, alternatively same amount energy expanded to a greater space means things are colder. Hot and cold here being rather irrelevant concepts, it is just energy in a volume of matter. Now as things have more energy they collide more often and with more force; which in turn means more pressure and more transfer of heat.
So this all simple as long as we stay in the realm of daily physics, but deep in the earth’s crust, on the surface of other planets and inside starts things get weird really quickly. But lets start close to the ground or rather in the ground, which is also where chemists and physicists who like to play with really high pressures, temperatures and energies like to have their labs incase of a rapid unplanned disassembly occuring.
If you look at the phase diagram I linked you might see that it doesn’t really keep for that long, ending at 647,094 Kelvin and mere 22,064 MPa. So whats beyond that? Well there we get in to the weird territory of supercriticality.
What is supercritical you may ask? Well imagine something is at the same time both liquid and gas. This should be easy, right? At 0 Celcius we can have ice, water and vapour! What’s the big deal? Well like I said things get strange when ever *critical* is applied to it. Supercritical water has funky property of simply not caring about limitations imposed to it as liquid or as gas, it has the benefits of both without the downsides. It can flow like water, and it can go through things like a gas. This is because at some point, water has so much energy that it simply doesn’t care and does what it wants. It’ll go through solid matter… well *solid matter*, if you ask Hydrogen then anything that is solid is more or less a speed bump than a barrier. What I mean to say, if you ram your car fast enough to a wall, you’ll go through it. Regardless how strong the wall is, your car can go through if you add enough energy to it. It might not be a car at that point, but what is car but a collection of molecules arranged in a particular way.
Right… So what happens if we can keep the water contained still. Prevent it from escaping IN TO the walls of our container. Well if you heat up even more, soon the water will break down to hydrogen and oxygen as both of them have different properties and given enough energy they’ll just go do their own things for a while.
So the molecule has broken down to it’s parts. While we are at it like we Finns like to say: “*Ei tunnu missään, löylyä lissää!*” – *Doesn’t feel like anything, add more steam!* So lets do that. Keep increasing the heat, we have come this far an our apparatus have yet to do a ventilation hole to the ceiling of the lab. As we add more energy the gasses become plasma, as in the electrons realise that they are strong independent particles who need no nuclei, and decide to go look for who they really are before permanently settling down again.
But we ain’t done yet! We can go even further! Dad ain’t home so lets give the thermostat a spin like we are playing wheel of fortune. As we add more energy, and pressure goes up, the fundamental particles start to break down to quark and gluons. And after that no matter how much energy you add, that is where things stop. You have reached the state of matter universe right after the big bang.
This exact question is what phase diagrams are for. What phase a particular substance is in depends on both temperature and pressure. [https://en.wikipedia.org/wiki/Phase_diagram#/media/File:Phase_diagram_of_water_simplified.svg](https://en.wikipedia.org/wiki/Phase_diagram#/media/File:Phase_diagram_of_water_simplified.svg)
Beyond critical point you can see there is no clear distinction between gas and liquid, such a state is called supercritical fluid [https://www.youtube.com/watch?v=-gCTKteN5Y4](https://www.youtube.com/watch?v=-gCTKteN5Y4)
To start with it would have to be a pretty strong vessel. As you add heat (energy) it will slowly raise temperature until right before boiling, (boiling point depends on the pressure of the “container”) then it would stop raising temperature and start changing state aka start turning into steam. The process of changing to steam will cause the contents of your container to expand roughly 1600 times its original volume creating pressure. As more and more heat is added the water won’t increase in temperature as it slowly turns to 100% steam (known as dry steam). Once you’re at 100% steam and keep adding heat it will now start increasing in temperature. This is called superheating and as the temperature goes up so will the pressure.
Side note: Heat causing a temperature change is known as sensible heat. Heat causing a state change is known as latent heat. It takes quite a bit more energy to cause a state change than it does to raise the temperature. If you measured the temp of a pot of water you would see the temperature of the water increase quite rapidly and then just sit there for a bit right before it actually starts boiling.
The higher you raise that steam temp, the more work you can do with it before it eventually falls back down in temperature and starts to condense. For example, at a 800mw power plant I worked at we brought the steam to 538 degrees before sending the steam to the turbine where it would do work rotating the turbine and generator before it condensed back to water to be sent back to the boiler.
Water is a great median for transferring energy from a heat source to do work.
>Would it just turn into a pressurized container full of steam?
This is the answer
>Would the water stay water but just like, really hot?
You could get this result if you add something.
If you put the water in a pressurized container, the boiling point would rise. So it wouldn’t boil at 100°C
Technically though, both of these are the case. Because as some of the water boils, it would raise the pressure, making it harder to boil the rest of the water
Steam would collect in the top of the bottle and push down on the water causing pressure to rise as well as the boiling point… this would keep happening until one of three things happened:
1. The container breaks
2. The water reaches the same temp as the heating element at a high pressure.
3. All the water turned to steam and the steam would heat up then to the heating element temp at high pressure
This concept is used in pressurized water reactors. If you read up on presurizer operations in thermonuclear pressurized water reactors you will get indepth views into all the complexities of this situation.
I spent years as a reactor operator on a 550MW nuclear reactor.
They make a thing called a “pressure cooker” that does this exact thing. I bet if you looked up “pressure cooker” on youtube it would be neat.
Latest Answers