Questions tagged [phase-diagram]

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64
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Why was water freezing almost instantaneously when shaking a bottle that spent the night outside during a frosty night?

Due to the forecasted frost last night, I placed yesterday evening, some 1.5l standard PET bottles filled up to 90% with warm tap water(+60°C) close to some vegetables that I wanted to protect in my ...
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1answer
15 views

What pressure does liquid nitrous oxide need at -45°C?

What pressure does liquid nitrous oxide need at -45°C to remain liquid? How can I calculate it's pressure required for other temperatures?
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0answers
21 views

Phase Diagrams - Hypereutectic, pro-eutectic phase

While designing some questions for my undergraduate class, I came across a scenario that is having me scratch my head. I am using the Cu-Ag phase diagram and arbitrarily selected Co = 90 wt.% Ag. My ...
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1answer
38 views

Why does adding salt to the water in a humidifier increase the amount of steam it makes?

Rather than "it decreases the latent heat of vaporization", can you explain why?
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1answer
23 views

Can the freezing point of Nitrogen be reduced?

There was an interesting Q/A about mixing helium and nitrogen. Is there anything that can be added to liquid nitrogen to reduce it's freezing point to below 63 kelvin?
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1answer
32 views

How to convert these from the given free energy $G$ vs $X$ to $T$ vs $X$ diagrams?

What I really do not understand is how they are converting from G vs X curves to T vs X. I have a couple of more diagrams with which I am having problems. A detailed answer to this is most welcome.
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0answers
20 views

Having doubt with how these diagrams have originated

This is written in the context of miscibility gap. What I do not understand is why delta H mix is greater than 0 for the situation. This is particularly written in context of systems with a ...
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0answers
11 views

Critical point for fusion curve

In phase diagram, on vaporization curve there exists a critical point beyond which a gas can not be liquifies but why does fusion curve does NOT end at a critical point and continues to infinity?
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1answer
79 views

Properties of water at a temperature of 300°C and a pressure of 3000 kPa

I'm using a online calculator, and it says that the boiling point of water at a pressure of 3000 kPa is 233.7°C. So then I understand that the water in is a superheated state (and thus still a liquid)....
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0answers
8 views

Why are spinodal points of such a great significance?

I can well understand that spinodal points have to do with inflection points in a G vs X curve but I do not yet understand why on earth do I need those points at all?Any guidance in the direction ...
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0answers
28 views

Where does the mass go in Clausius-Clapeyron approximation for ideal gases?

I am currently studying Clausius-Clapeyron equation at university. One of the proposed problems asked us to find the latent heat of vaporisation of camphor using ideal gas laws. In the solution by my ...
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0answers
21 views

Proving this modified classical 2D Ising Hamiltonian has a phase transition

Consider the following Hamiltonian with a local Hilbert space $\mathcal{H}=\mathcal{H}_\Delta\otimes \mathcal{H}_{Ising}\cong\mathbb{C}^2\otimes\mathbb{C}^2 $. Denote an $L\times L $ square lattice as ...
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3answers
67 views

R134a state at rest

I'm a mechanic and I've had a question for some time regarding AC systems that no one in my garage seems to be able to answer (or care actually). R134a has a boiling point at -26°C at atmospheric ...
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0answers
23 views

Is it possible to have three stable liquid phases in a binary mixture?

With this system, it would be possible to have three liquid phases and two liquid-liquid coexistence regions at various compositions. Similar behaviour is common for solids such as alloys, sometimes ...
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3answers
79 views

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 ...
4
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2answers
677 views

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 ...
3
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1answer
98 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 ...
1
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1answer
35 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 ...
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0answers
32 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 ...
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0answers
30 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 ...
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1answer
18 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 ...
0
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1answer
50 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. ...
2
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3answers
337 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 ...
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1answer
31 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 ...
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0answers
38 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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1answer
168 views

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 ...
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0answers
29 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 ...
5
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1answer
113 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 ...
4
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1answer
109 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 ...
3
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1answer
98 views

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 ...
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1answer
74 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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1answer
286 views

Is there any relevance between phase diagram and energy?

                               Phase Diagram for Carbon Dioxide I watched ...
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2answers
190 views

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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1answer
40 views

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?
0
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1answer
37 views

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 ...
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2answers
118 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}{\...
4
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1answer
343 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 ...
0
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1answer
85 views

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 ...
2
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0answers
362 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 ...
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1answer
184 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 ...
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0answers
46 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 ...
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2answers
150 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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1answer
105 views

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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0answers
14 views

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 ...
3
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3answers
753 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)
2
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1answer
235 views

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 ...
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0answers
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 ...
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0answers
32 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 ...
3
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1answer
272 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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0answers
200 views

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 ...