Eli5 what would happen if you had water in a completely sealed container and brought it past boiling temp

Question

Would it just turn into a pressurized container full of steam? Would the water stay water but just like, really hot?

In: 98

Answer 1

This is the application of a phase diagram.

Wiki is nice enough to show a simple example of water (in reality, solid water is super complex, consisting of multiple types of ice depending on conditions, but we don’t care about solids)

https://en.m.wikipedia.org/wiki/Phase_diagram

As water is heated you would reach an equilibrium where the additional volume occupied by the steam increases the pressure in the chamber where no additional water can evaporate. The hotter you get, the more pressure is required and that equilibrium mix of liquid and gas shift up, increasing the pressure.

Eventually you reach the critical point where water is indistinguishable as a liquid or gas. It becomes another state of matter.