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Questions tagged [phase]

An entity of a material system which is uniform in chemical composition and physical state. This tag should be applied to question regarding chemical and physical properties of phases, systems of phases and also phase transition processes.

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Why do we have water vapor at room temperature and atmospheric pressure when water is a compressed liquid at these conditions?

At room temperature and 1 atm pressure liquid water should be a compressed liquid. Now if that is the case then why do we have water vapor at these conditions? I can't make sense of this based on just ...
chem_101_102's user avatar
4 votes
1 answer
54 views

Undiscovered kinetically-hindered metastable phases

The majority of solid chemicals have multiple meta-stable phases. This means that there are multiple different crystal structures that are kinetically stable. For example, aragonite and calcite are ...
Kevin Kostlan's user avatar
1 vote
1 answer
54 views

Could the presence of multiple stabilizer oxides induce sluggish diffusion in a stabilized zirconia to increase lifetime?

The presence of yttria stabilizes zirconia's high temperature allotropes, but it also decreases the lifetime due to more defects that can induce more diffusion into yttria rich and poor regions, ...
user145034's user avatar
2 votes
0 answers
63 views

Would fluorides stabilize zirconia?

The reason for zirconia's cubic and tetragonal phases not being stable is that the cation-anion ratio is too small for proper contact between ions. One way is to use other oxides that have a bigger ...
user145034's user avatar
1 vote
0 answers
16 views

Freezing-Point Depression and Boiling- Point Elevation diagram

Hey I don't understand how can it be that the phase diagram of the solvent in a solution, can be separated from of the overall solution? isn't the freezing or melting and etc is of the whole solution? ...
miiky123's user avatar
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5 votes
0 answers
68 views

Is there such thing as metallic helium?

I know that hydrogen can behave as a conductor under high pressure (metallic hydrogen); however could helium behave similarly under high pressure? If so, could this have any potential benefits over ...
Nitrogen-8's user avatar
0 votes
0 answers
47 views

Dependence of Chemical Potential in Derivation of Clapeyron Equation

The "standard" derivation of the Clapeyron equation begins with considering two phases $\alpha$ and $\beta$ that are in equilibrium. The claim made is that $$\mu^\alpha(T,P) = \mu^\beta(T,P)$...
Neel's user avatar
  • 31
0 votes
3 answers
113 views

Why is that during a phase transition, a single melting point exists for melting?

I know that during melting, latent heat is used in increasing potential energy (as intermolecular distance increases) of the complete structure of given solid to liquid. But it can also happen ...
rimor's user avatar
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8 votes
1 answer
308 views

Do all three states need to be present at triple point?

A recent United States National Chemistry Olympiad question asked the following: Which statement best describes a sample of ammonia at equilibrium at its triple point (195.4 K, 0.0606 bar)? A) ...
unstable's user avatar
  • 198
-2 votes
1 answer
52 views

Heating a Single Water Molecule [closed]

From my understanding, phase changes break/form bonds between molecules of the same substance. Assuming this is in a vessel at 1atm of inert gas, if I have one molecule of water with no bonds to other ...
Camel Camel's user avatar
0 votes
1 answer
50 views

Pressure in Clapeyron and clausius Clapeyron equation

The Clapeyron equation is $\frac{\mathrm{d}p}{\mathrm{d}T}=\frac{\Delta S}{\Delta V}$. Here, is the change in pressure 'dp' actually a change in external pressure that is being applied on the whole ...
Natasha J's user avatar
  • 259
-2 votes
3 answers
120 views

Interpretation of a Phase Diagram

I am a bit confused about the correct way to interpret a phase diagram. I was told that the line separating the liquid and gas phases gives the vapor pressure of the liquid substance as a function of ...
Johnny Smith's user avatar
12 votes
1 answer
719 views

Covalent network phase of CO2

In a science essay in the November 1999 edition of Analog magazine by Stephen L. Gillett¹, Gillett speculated on the possibility of a compound he dubbed "diamond ether". The name derived ...
M.Hutson's user avatar
  • 193
0 votes
1 answer
91 views

synthesis of Red Lead, Pb3O4

I have tried heating $\ce{PbCO3}$ at $\pu{400 ^\circ C}$ temperature to form $\ce{Pb3O4}$. After sometime of heating, only a layer of $\ce{Pb3O4}$ is made and the reaction does not complete. The ...
Jak's user avatar
  • 11
-4 votes
2 answers
68 views

Can phase tranformations occur with change in temperature? [closed]

I know that, usually, phase transition occurs with a fixed temperature. Is there a case where this is not followed? Can phase transformations occur with changing/variable temperature?
ananta's user avatar
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2 votes
1 answer
103 views

Is a hydrogen atom 'locked' to a given oxygen atom in ice?

Ice, Hydrogen bond, and Ice rules Wikipedia articles seem to imply that the covalently bonded hydrogen atoms are fixed to their given oxygen atom and do not change positions as long as the ice remains ...
ericnutsch's user avatar
0 votes
0 answers
42 views

Do we group reversible reaction with all reactants and product solid as homogenous or heterogeneous equilibrium?

My personal thought is that they should be in heterogenous equilibrium as we define it as all reactants and products being of different phase (phase-their must not be a visible boundary) and solids ...
COMan25's user avatar
2 votes
2 answers
127 views

Fractional Distillation Question

We're covering fractional distillation in my physical chemistry class. I'm confused regarding this diagram: From your starting point, you heat the binary mixture (in this case benzene and toluene) to ...
GMoss's user avatar
  • 311
0 votes
1 answer
115 views

Sign of ∆S in conversion of diamond to graphite

It is said that ∆S is positive as randomness is increasing from diamond to graphite as in diamond molecules are tightly packed together but we know that ∆S=∆H/T for phase transition and that ...
S K's user avatar
  • 33
-3 votes
1 answer
77 views

Liquification of ideal solution of two liquids from vapor phase [closed]

A and B form an ideal solution. In a cylinder piston arrangement, $\pu{2.0 mol}$ of vapor of liquid A and $\pu{3 mol}$ of vapor of liquid B are taken at $\pu{300 torr}$ and $T~\pu{K}$. At what ...
om Makadia's user avatar
0 votes
0 answers
46 views

How can two separate phases interact with each other in an separatory funnel

Hello I was thinking about the following process. I was working in the lab, and synthesized a chelator for various metals, iron, copper etc.; however, when extracting the mixture with water and ethyl ...
Mäßige's user avatar
  • 127
6 votes
0 answers
156 views

Which xylenes, if any, are immiscible with DMSO?

"Xylene" is reported to be immiscible with dimethyl sulfoxide (DMSO), according to a few solvent miscibility tables found online (chart 1, chart 2, chart 3). I have tried to locate some ...
Anger Density's user avatar
11 votes
0 answers
90 views

Is gallium slippery at room temperature in an inert atmosphere?

Ice is slippery when it isn't too far below it's melting point because the surface molecules are less loosely bound than the bulk and form a thin liquid layer. Pressure melting is a much smaller ...
Kevin Kostlan's user avatar
2 votes
0 answers
69 views

How do I plot ternary phase diagrams using Flory-Huggins solution theory?

I have three components, $A,B,C$, with 3 exchange parameters: $\chi _{AB}, \chi _{BC}, \chi _{AC}$. I want to create a FH ternary diagram to see how such a mixture behaves and how phase separation ...
bad_chemist's user avatar
5 votes
1 answer
230 views

Why can't the change in a crystal structure be due to the rotation of octahedra?

I have the following information about barium titanate ($\ce{BaTiO3}$). It adopts the perovskite structure and has a phase transition from a cubic to a tetragonal phase at 120 °C. The space group of ...
Krabz Henge's user avatar
3 votes
1 answer
57 views

Are there distinct phases of amorphous ice?

Amorphous ice is a solid phase of water that lacks crystal structure. It is stable below about 150K, above which it converts to crystalline ice. There are four phases of amorphous ice: low medium, ...
Kevin Kostlan's user avatar
-4 votes
1 answer
96 views

What is the relationship between solutions and changes to states of matter?

For example, when liquid water evaporates, my instinct is to say that of course it's become gas, but I'm a bit unsure because, if I understand correctly, evaporation occurs because air dissolves the ...
Mikayla Eckel Cifrese's user avatar
6 votes
1 answer
442 views

Does "brine rejection" happen for dissolved gases as well?

"Brine rejection" is the effect of sea ice pushing out dissolved salts, forming sweetwater ice and brine. I understand "freeze distillation", a method to concentrate alcohol in ...
HannesH's user avatar
  • 483
3 votes
0 answers
72 views

Why does gallium expand on solidification

I've heard that Ga exist as Ga2 molecules in its crystal lattice. Does that have anything to do with expansion of Ga while solidifying? Why and how does it actually expand?
Neet aspirant's user avatar
4 votes
0 answers
66 views

Is there experimental evidence to show boiling point increases with external electric field, and if so, by how much?

I was wondering whether anyone has demonstrated that a liquid will have a higher boiling point if it is placed in a very large electric field. I believe to be the case, since induced dipoles would be ...
Kyky's user avatar
  • 149
-1 votes
2 answers
248 views

When we boil water, does the generated steam remain at the same temperature of boiling point until all water is boiled? [closed]

Suppose we are boiling water in such conditions so that the boiling point of water be $\pu{100 ^\circ C}$. Does the generated steam have the same temperature of 100 C until all water is boiled? And ...
Osmium's user avatar
  • 222
1 vote
0 answers
38 views

How to get Raman shift frequency values from neutron scattering measurements?

I have read some papers that say that a Kohn anomaly mode is a particular feature of 2H- transition metal dichalcogenides and that the existence of such a mode can be seen in neutron scattering data ...
John's user avatar
  • 65
0 votes
1 answer
2k views

Methanol/water mix freezing point vs specific gravity?

I need to determine the freezing point of the methanol-water mix in the ground loop of my heat pumps. I have a hydrometer and have measured the specific gravity as 0.905. How do I convert this to a ...
Gary Aitken's user avatar
1 vote
1 answer
57 views

More minerals in seawater at greater depths?

There are lists such as the one below detailing how much of different minerals seawater contains: https://web.stanford.edu/group/Urchin/mineral.html (For instance ) Would you expect this to be the ...
Agerhell's user avatar
  • 127
0 votes
0 answers
39 views

How to determine whether a reaction is possible by using a phase diagram?

Given the following phase diagram for a binary mixture of $\ce{MoO3}$ and $\ce{Bi2O3}$: I am asked to determine whether from $\ce{Bi2O3}$ and $\ce{Bi6Mo2O15}$, can $\ce{Bi10Mo3O24}$ and $\ce{...
HWIK's user avatar
  • 17
2 votes
1 answer
229 views

Formation of AZ91 Magnesium Alloy

I have been researching on how to form AZ91 Common Magnesium Alloy which consists of 90% Mg, 9% Al, 1% Zn, 0.3% Mn. Referring to the article at here, I have read and highlighted important text and ...
jessica smith's user avatar
2 votes
1 answer
48 views

Why is the fugacity of a pure component not equal to the pressure calculated by an equation of state for that pure component?

I don't get why fugacity coefficients, $\phi = f/p$, of pure components are usually calculated via integrating an eos over a pressure or volume range. For example, when using a pressure explicit eos (...
AimLow's user avatar
  • 21
0 votes
1 answer
272 views

Why the density of liquid decreases and density of vapour increases as we approach towards the critical state/point

Pressure and temperature have opposite effects on density. As temperature increases at constant pressure density decreases and as pressure increases at constant temperature the density increases (and ...
Abhishek P G's user avatar
2 votes
0 answers
87 views

Is there a chemical compound which does not have a liquid state but a solid and a gaseous state? [duplicate]

Is there a chemical compound which does not have a liquid state but a solid and a gaseous state? Meaning no matter the temperature or pressure it will never be in its liquid form. According to my ...
SirHawrk's user avatar
  • 137
8 votes
1 answer
364 views

Does water expand on freezing more than any other known substance?

Several substances expand on freezing. Gallium expands 3.1% and bismuth 3.3%. However, both of these are much less than water which expands 9%. Is there any substance that expands more than 9% on ...
Kevin Kostlan's user avatar
-1 votes
2 answers
88 views

Spontaneity criterion for phase transformations and chemical reactions [closed]

Why is the Gibbs free energy (G) considered a spontaneity criterion for phase transformations and chemical reactions? Why are other thermodynamic parameters such as enthalpy (H), entropy (S), and ...
Akshit Dhillon's user avatar
1 vote
3 answers
966 views

Why does equilibrium of ice and water only exist at 273K at normal pressure?

I am a high school student and I am a little confused in the concept of spontaneity of a reaction and how equilibrium works for a reaction, I got some confusions: Let's take example of freezing of ...
Arun Bhardwaj's user avatar
10 votes
1 answer
833 views

Are molecules exchanged between a solid and liquid in equlibrium?

In Vapor-Liquid Equilibrium, it is my understanding that molecules exchange between the gas and liquid continuously; even when no difference in temperature or partial pressure exists. Regarding Solid-...
ericnutsch's user avatar
6 votes
1 answer
259 views

Water getting hotter once frozen?

I packed a fridge with temperature sensors and took over the temperature control in order to have extra cold beer. One of those sensors is submerged in the middle of a container containing a 4.5% ...
Francois's user avatar
  • 171
1 vote
0 answers
241 views

What polyatomic substances have the lowest known freezing points at standard pressure?

At standard pressure, helium never freezes, so that's clearly the coldest liquid—but it's also a monatomic substance. Diatomic hydrogen freezes at 13 K. Neon freezes at 24 K. And then the next coldest ...
Logan R. Kearsley's user avatar
-3 votes
1 answer
105 views

Melting and Freezing [closed]

Ok so I needed some help understanding one concept, for eg:- we are in an isolated room that has a room temperature of 0 degrees Celsius. And I bring in some water in the room, so eventually it will ...
falkon's user avatar
  • 17
3 votes
2 answers
165 views

Explaining the process of boiling a liquid

I am confused by the thermodynamic definition of boiling. It is stated that boiling occurs when the vapor pressure of a liquid is the same as the ambient atmosphere. Now suppose we deal with an open ...
Mäßige's user avatar
  • 127
2 votes
0 answers
199 views

Interpreting Ternary Phase Diagram Stoichiometry

I am trying to locate the lowest-melting mixture in a system of three nitrate salts: sodium, potassium, and calcium nitrate. I have the relevant ternary phase diagram, but I am unsure exactly about ...
Anger Density's user avatar
3 votes
1 answer
515 views

Doesn't the eutectic diagram violate Gibbs's phase rule?

EDIT: As the question hasn't attracted any answers, I tried to put in more detail. Gibbs's phase rule for a 2 component system at constant pressure says that $F=3-P$, i.e., that the number of degrees ...
FusRoDah's user avatar
  • 772
0 votes
0 answers
63 views

Solubility of multiple solutes and limits of solubility during freezing

I'm interested in modeling the freezing of solutions of water and I'm not really sure what happens in water after the solubility of a given material is reached. I know that as ice crystals form they ...
Jake's user avatar
  • 217

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