# Questions tagged [phase-diagram]

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### Why are there two states of matter in a bottle of gas?

Say a bottle of natural gas used for heating or cooking. There is a liquid phase, which I believe is the densest part, at the bottom of the bottle. And on top of it, there is presumably gas in a ...
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### Does the density of ice increase further when it is further cooled?

As we know, water becomes ice at $0^°$C. After becoming ice, if we lower the temperature further ($<0^°$C), then does the density of ice increase further? If yes, in that case, does the volume ...
82 views

### How can Water exist in two different liquid states at the atomic scale?

We know how unique water is and this question is based on a recent discovery that water can exist in two different liquid states. The density of the two states vary by almost 20 %. Can someone explain ...
17 views

### Shouldn't the projection on the y-axis, of a radial vector in a circle making an angle theta with the x axis, also be the radius?

I don't understand this diagram... the projection is meant to be a shadow, right? So shouldn't the shadow of the radial vector as shown in the circle on the y-axis, be the entire y-axis (since the ...
26 views

### First-Order Phase Transition

When the density/volume abruptly changes (isobar/isothermal) while providing a sufficient latent heat to the system, is this variation related to a high compression/expansion as it is illustrated to ...
22 views

### Understanding liquid-liquid phase separation

The above figure shows how the regular-solution free energy might lead to liquid–liquid equilibrium. In the region between the compositions $x^I_A$ and $x^{II}_A$, $G$ increases with $x_A$. If the ...
14 views

### Liquid-Vapour Surface Tension

In a multi-phase system with a liquid which meets a gas at the free surface, one can define liquid-vapour surface tension $\gamma_{LV}$: is this surface tension a constant when one varies the pressure ...
41 views

### What happens physically in a second-order liquid-gas phase transition?

I know the difference between first and second order phase transition in terms of the discontinuity of the derivatives of free energy. I am curious to know what happens as the system is viewed. ...
146 views

### Why water behaves strangely at 4 degree celsius?

The basic physics concept I hope almost every one might be aware of i.e "water tend to expand instead of freezing just below and above 4 degree celsius". My question is why exactly at 4 ...
28 views

### Question concerning phase curves and Lissajous figures

I want to draw the "orbits" of a spherical pendulum under small oscillations. In this case its equations are given by $\ddot{x}_{1}=-x_{1}$ and $\ddot{x}_{2}=-x_{2}$. Of course the potential ...
32 views

### What happens above critical point, gas or supercritical fluid?

When the temperature of a substance exceeds its critical temperature and its pressure exceeds the critical pressure, it becomes a supercritical fluid. This is a generic phase diagram: On the other ...
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### Is there a state of matter with no definite volume but definite shape? [closed]

Essentially I am wondering since solids have definite shape and volume, liquids have definite volume, and gases have neither definite volume or shape if there was a state of matter that can change ...
26 views

### Can phase diagrams be obtained by Helmholtz energy minimization?

I know that in calculating phases of materials it is standard to choose a pressure $p$ and temperature $T$ of interest and then, keeping these two quantities fixed, find the mixture of phases that ...
95 views

### First-order phase transitions as branch cuts

First, I apologize for the long preface to my question. The actual question is in bold below. In Kardar's Statistical Physics of Fields, on page 10, the author writes, "the free energy of the ...
101 views

### Continuous Transition From gas to liquid

Consider the following figure: Let us suppose we were at some point in gaseous phase. Can we go from gaseous to liquid phase by moving about critical point continuously? Why isn’t any critical point ...
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### Why does critical temperature exist?

This question has been previously asked over here and the comment and answer there has already answered my original question (the one that I had in my mind), but the following question arises: Why ...
62 views

### Why does diamond-graphite phase digram not contain a critical point?

I was curious as to why in all the diagrams I have seen that the diamond-graphite phase diagram does not display a critical point, do all substances eventually reach a critical point?
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### Is there any relevance between phase diagram and energy?

Phase Diagram for Carbon Dioxide I watched ...
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### How to differentiate solid, liquid and gas on the basis of symmetry breaking? [closed]

I want to ask this question how to solid, liquid and gaseous state arises due to the concept of symmetry breaking?
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### Quark gluon plasma at arbitrarily high temperature

Does the quark-gluon plasma become weakly coupled at infinite temperature (due to asymptotic freedom), or does it maintain some non-perturbative behavior?
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### Why do some textbooks use $T$-$V$ diagram for temperature table instead of $p$-$V$ diagram?

I am confused about this thing. In the temperature table, the first column explains specific temperature and the second column explains corresponding saturation pressure. From what I understand, if ...
114 views

### Phase diagram method

I was trying to find the famous attractor solution of the inflaton field which follows the equation \frac{d\dot{\phi}}{d\phi}=-\frac{\sqrt{12\pi}(\dot{\phi}^2+m^2\phi^2)^{1/2}\dot{\phi}+m^2\phi}{\...
167 views

### Why is temperature and pressure constant during a phase transition?

During a phase transition, I have read that phase transitions occur at constant pressure and temperature. The explanations I have found both in books and online for this is that all the energy ...
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### Why can you find running water lower than $0^\circ \text{C}$?

I was looking at the phase diagram for water: It seems there is not much of a region on the diagram at which you can be in the liquid phase, for temperatures lower than $0^\circ \text{C}$. I am ...
244 views

### What is the Haldane phase?

I'm trying to look up what is the Haldane phase, but the only thing I find is examples of physical systems that "realize" the Haldane phase, such as the AKLT model, but no clear definition of what ...
137 views

### Surface tension and definition of boiling point

The boiling point of a substance is defined as the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. Does the pressure ...
43 views

### Function to describe changes in water's phase diagram

I measured the barometric pressure over 4 days and I obtained the next image: The Y axis is the pressure in hPa and the X axis is the time (4 days) I think it is very interesting the fact that the ...
124 views

### Can vodka turn to a solid?

How can I turn vodka into a solid? If I boil it, and then cool completely, will it still be a liquid? Is there any way to turn vodka to a solid?
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### How to graph the properties of steam?

I need to render this graph in Unity: I'm using this as a resource: http://www.iapws.org/ I've found various implementations of IAPWS (95, 97, etc...) in various languages (python, c++, fortran, ...
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### Does anyone knows where can I find the phase diagram of oxygen free copper (OFC or OFHC)?

I am having problems with a niobium deposition I made on a substrate. I increased the temperature to 500 degrees celsius and in theory the film should have a better quality. However this wasn't the ...
584 views

### Shape of isotherms in $P$-$V$ phase diagram

Please explain the shape of the isotherms in this P-V phase diagram. In particular, why are the isotherms flat in the liquid-vapor region? (image from Lumen Learning | Physics | Phase Changes)
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### Why doesn't the phase diagram of water look different?

How can sublimation occur at much lower temperatures than 0 degrees celsius provided that the pressure is sufficiently low? The melting point of water is relatively unaffected by the external pressure ...
46 views

### Thermodynamics, Phase change diagrammes

What would be the phenomena and PV, TV diagrammes for a closed vessel partially filled with water and subjected to heat, How change in vapour pressure would effect its boiling?, How PV, TV diagrammes ...
31 views

### Phase diagram of a fluid

How is it look like the phase diagram of a fluid in density-pressure plane? I came across the phase diagram in Pressure-temperature plane most of the time. But I can't find the phase diagram in ...
229 views

### How to interpret phase diagrams?

I find quite difficult to interpret phase diagrams in general, for example I see people discuss them along the following lines: Here we see the coexistence line between liquid-solid phases.. a ...
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### Why does placing liquid nitrogen in a low pressure chamber lower its temperature?

As you can see in this demonstration and read in this Wikipedia article if you were to place a cup of liquid nitrogen in a low pressure environment then it would reach a triple point and begin to ...
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### Is the triple point of water exactly 0.01 $\deg$C?

Is the triple point of water exactly $0.01 \deg$C, or is this an empirical value/is there some uncertainty to it? If so, how do we know it is exact, and why?
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### What's the difference in a PV diagram that is curved versus one that is straight?

So what would the difference be between the graph above versus one that has the same inital and final points but the path is curved. I'm sure it has something to do with temperature, so does it mean ...
156 views

### Is it possible to have a planet entirely made out of liquid water?

Earth is mostly covered in oceans, but they only go a few kilometres deep. It's obviously not possible to have a planet the size of the earth to be made entirely out of water, because of the kind of ...
231 views

### Multiple Triple Points

I was reading Chandler's Introduction to Modern Statistical Mechanics and noticed a strange feature in one of the figures. The phase diagram in the image has two triple points; however, according to ...
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### Phase of refrigerant when entering evaporator?

In the diagrams for refrigeration cycle(vapour-compression), the refrigerant at the inlet to the evaporator lies under the vapour dome i.e partly vapour and partly liquid. Now i have been studying ...