Water vapor at approx. 300 degrees Celsius


by fawk3s
Tags: approx, celsius, degrees, vapor, water
fawk3s
fawk3s is offline
#1
Jul26-10, 07:31 AM
P: 342
Ive heard that at somewhere around 300 degrees Celsius (cant remember the exact number), you cant liquidise it anymore. Is this fact correct?

Thanks in advance,
fawk3s
Phys.Org News Partner Physics news on Phys.org
The hemihelix: Scientists discover a new shape using rubber bands (w/ video)
Mapping the road to quantum gravity
Chameleon crystals could enable active camouflage (w/ video)
Dadface
Dadface is offline
#2
Jul26-10, 07:44 AM
PF Gold
Dadface's Avatar
P: 2,004
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.
fawk3s
fawk3s is offline
#3
Jul26-10, 07:54 AM
P: 342
Thats what I thought. Thanks !

AJ Bentley
AJ Bentley is offline
#4
Jul26-10, 09:41 AM
AJ Bentley's Avatar
P: 665

Water vapor at approx. 300 degrees Celsius


Quote Quote by Dadface View Post
results not in a liquid but in a compressed vapour.
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.
Jobrag
Jobrag is offline
#5
Jul26-10, 01:03 PM
P: 459
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
Dadface
Dadface is offline
#6
Jul26-10, 01:17 PM
PF Gold
Dadface's Avatar
P: 2,004
Quote Quote by Jobrag View Post
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.
AJ Bentley
AJ Bentley is offline
#7
Jul26-10, 01:20 PM
AJ Bentley's Avatar
P: 665
Ah, yes, the critical point is 374 degrees C. (The OP did say 'about' 300)
It's surprisingly low though.
K^2
K^2 is offline
#8
Jul26-10, 02:11 PM
Sci Advisor
P: 2,470
I'm pretty sure what OP heard is a mention of critical point. Sounds like it. Past these 374C, 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.


Register to reply

Related Discussions
Two separate flasks are each filled with a gas at 25 degrees Celsius; the valve betwe Biology, Chemistry & Other Homework 1
Thermodynamics: Water vapor vessel plunged into water ice bath Engineering, Comp Sci, & Technology Homework 5
-40 Degrees Celsius General Engineering 3
degrees of freedom - molecule of water vapor General Physics 1
Do O2 gas and diphosphate combust at approx 40 degrees C? Chemistry 2