Does Increasing Pressure Increase Melting Point

emailanmol · Mar nineteen, 2022

Hey, I take read that INCREASING the external pressure on solids INCREASES their melting signal.(except for ice)

WHY DOES THIS HAPPEN?

(This is similar to the upshot on Boiling signal which rises when external force per unit area is increased.
I know this happens considering humid takes place at temp where vapour force per unit area of liquid land is equal to external pressure level and since external pressure level is college , the liquid volition boil at a higher vapour pressure level.And since vapour pressure is proportional to temp , a college temp is needed to eddy the liquid.)
CAN YOU EXPLAIN WHY THIS HAPPENS FOR MELTING POINT USING SIMILAR ARGUMENTS?

ii)

Also WHAT IS THE DEFINITION OF MELTING POINT.(Lol.I dont want answers saying temp where solid converts to liquid.)
I want information technology in terms of pressure(like the way its defined for boiling indicate, tenp at which vapour pressure of liquid equals external pressure)

I am guessing MELTING Signal is TEMP at which SOLID VAPOUR Force per unit area is equal to LIQUID VAPOUR PRESSURE
AM I RIGHT?

moogull

The virtually simple interpretation I think is like this: if yous are pushing down harder on a substance (i.eastward. more than pressure level) then a molecule must overcome a greater force to break gratis from the forces holding information technology together as a solid and become a liquid or gas. Therefore y'all have to have a greater temperature in order for information technology to take plenty energy to break solid bonds? There is not physics to this respond actually, only I'll start looking in a thermo book I have and come up with a better answer in terms of force per unit area.

emailanmol

Hey, Moogull.

Thanks so much for your reply (and effort)
Y'all make a keen signal.

Incidently even i was thinking that molecules would need more kinetic energy to escape than before and thus a college temp.

It would be really cool if someone comes up with something in terms of vapour pressure :-)

moogull

I'g in class right now, but I'll detect something for you to look at, don't worry!

moogull

I'm not so sure that vapor pressure would be a skilful way to think about a melting phase transition. I wouldn't become so far as to say that solid vapor pressure and liquid vapor pressure are equal. Here is a link almost vapor pressures for solids and liquids: http://www.chem.purdue.edu/gchelp/liquids/vpress.html

If you were to take a mixed land (solid and liquid), or but a solid or a liquid of a substance in a closed container and so there would just exist one vapor pressure that you could mensurate. I don't know if solid vapor force per unit area vs. liquid vapor pressure level is conventional. In fact if you have a solid in a closed container then at certain pressures (for certain substances) it will sublimate/become directly to a gas and that is where you take solid vapor pressure, but if you accept a substance that is melting, I don't know too much virtually the vapor pressure level in that container. I guess there would be some contribution to vapor force per unit area from the liquid and peradventure from the solid as well, but if the liquid is less dumbo so information technology will be sitting on top of the solid and the liquid will be the 1 contributing to vapor pressure (in a continuum like model).

Here is some other link that talks nearly the thermodynamics of melting in crystals (its a pdf)
Thermodynamics of Crystal-Melt Phase Change

That resource talks virtually phase changes in terms of enthalpy. I haven't done likewise many searches, only it seems like vapor pressure is not talked most too much in melting stage change.

DrDu

I'm not so sure that vapor force per unit area would exist a good mode to recall most a melting phase transition. I wouldn't get so far as to say that solid vapor pressure and liquid vapor pressure are equal.

No, emailanmol is correct. Both liquid and solid are in equilibrium and apparently are in equilibrium with the vapour. Hence vapour pressure has to be the aforementioned. If not, e.g. liquid would evaporate and condense on the solid.

The alter of the stage equilibrium line with force per unit area is given by the Clausium Clapeyron equation
dT/dp=T Delta V_m /Q_m, where Delta V_m is the difference of molar Volumes of the two phases and Q_m the heat of melting. To bear witness this relation, you demand a good deal of thermodynamics:

http://en.wikipedia.org/wiki/Clausius–Clapeyron_relation

emailanmol

Hey, the links you posted are astonishing. This is all that I needed.Now I take better understanding.
Thanks a lot

moogull · Mar nineteen, 2022

Thanks DrDu,

Every bit he said, at that place is a lot of thermo backside the euqation, and I am only in my showtime semester of it so I'm kind of shooting in the nighttime. Question to DrDu, so solid vapor pressure would exist those molecules that boil off of the solid and liquid vp is off of the liquid, then would the full vapor pressure in a closed container be equal to charge per unit of condensation plus charge per unit of deposition?

emailanmol

Hey DrDu,

Thanks for clearing that up.Could y'all explain in laymens' terms on how solid vapour pressure level depends on temp and external presure.
Does it increase or does information technology subtract or remains constant.

Does Increasing Pressure Increase Melting Point

Effect of pressure on Melting point

Answers and Replies

Related Threads on Event of pressure level on Melting point

Does Increasing Pressure Increase Melting Point,

0 Response to "Does Increasing Pressure Increase Melting Point"

Post a Comment

Iklan Atas Artikel

Iklan Tengah Artikel 1

Iklan Tengah Artikel 2

Iklan Bawah Artikel