# Water vapor at approx. 300 degrees Celsius

1. ### fawk3s

342
Ive heard that at somewhere around 300 degrees Celsius (cant remember the exact number), you cant liquidise it anymore. Is this fact correct?

fawk3s

You can liquidise a vapour by applying a high enough pressure but only if the vapour is at a temperature lower than its "critical temperature".If the temperature is higher than the critical temperature then applying pressure results not in a liquid but in a compressed vapour.

3. ### fawk3s

342
Thats what I thought. Thanks !

4. ### AJ Bentley

664
This shows up the difficulty with using common terms in science - a supercritical fluid is neither liquid nor gas. (And yet it's both at the same time).

Is a liquid crystal a solid or a liquid? - Same problem.

5. ### Jobrag

526
I'd need to check a book of steam tables but I'm pretty sure that water can still be aliquid at a lot more then 300 Deg C

I just checked and the critical temperature of water is 374Deg C.

7. ### AJ Bentley

664
Ah, yes, the critical point is 374 degrees C. (The OP did say 'about' 300)
It's surprisingly low though.

8. ### K^2

2,470
I'm pretty sure what OP heard is a mention of critical point. Sounds like it. Past these 374°C, there is no phase transition from vapor to liquid, and that might come out as "can't liquidise" to someone who didn't quite get the point.