# Questions tagged [phase-diagram]

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### Lower pressure lower boiling point

Is there an intuitive way for understanding why in lower pressure the boiling point is lower? Maybe some easy characteristic special case. Or should I just follow equation or experiment and memorize ...
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### What is the energy needed to convert 200 kg water (25C) to steam (150C, 6 Bar)? [closed]

I am having problem in finding how to convert water (25C) to Steam (150C, 6 Bar).
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### Why does bubble formation only happens at the point when vapor pressure becomes equal to atmospheric pressure during boiling?

I am a high school student and I am very confused about what's actually happening at the microscopic scale in an ideal solution when it's boiling? Boiling as I understand at microscopic level is- ...
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### Can Solid takes the shape of its container

My Cambridge Physics Coursebook says that Solid "takes the shape of its container". It is endorsed by Cambridge for IGCSE physics. Is it right? How is this possible. It is very Clear and ...
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### How to estimate the pressure drop due to venting?

For context, I'm writing a small simulation to predict the behavior of a pure substance within tanks, pipes, valves and so on for entertainment purposes. I have an issue to simulate venting. Here is ...
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1 vote
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### If no amount of pressure can liquefy a gas at critical temperature, why does it liquefy at critical pressure?

I have read that at the critical temperature, no amount of pressure will liquefy a gas but according to the definition of critical pressure, a gas at its critical temperature will liquefy at a ...
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### What might get me to the lowest temperature with liquid water?

I'd like to experiment with freeze drying food but the only equipment I own, is a vacuum pump+chamber and an old freezer I wouldn't mind drilling to run a vacuum pipe inside. However an important ...
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### Why is the supercritical fluid region a perfect rectangle?

The melting, sublimation and evaporation curves are all non straight lines in a (p,T) phase diagram, while the curves that divide liquid/gas regions from supercritical fluid region are perfectly ...
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### Van der Waals equation in PT coordinates

Can Van der Waals equation be meaningfully interpreted in PT plane? Are there modified versions of this equation, which would allow correctly reproducing the liquid-gas separation curve with a ...
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1 vote
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### Calculating phase diagram for immiscible system

I want to calculate the phase diagram for the Al-In system, which has an immiscible phase. As the solid elements don't have any mutual solubility, there is no excess Gibbs description for the solid ...
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### Will interstellar helium condense to a liquid as space expands and cools?

Intergalactic space is 2.7K (https://en.wikipedia.org/wiki/Outer_space) Interstellar space is a little warmer. My understanding is that these will decrease over time. The phase diagrams of helium I ...
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### Dependence of phase transition on scale factors

In a numerical experiment, I have obtained a phase diagram of the system under study. The phase diagram is obtained between two scaled quantities say, $P^{\prime}$ and $Q^{\prime}$ of the system. I ...
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### Are number of molecules per unit volume constant (say in water)?

I have a very basic doubt. I knew that $$\rho = \frac{m}{V}$$ And since mass is constant so volume may decrease or increase depending upon density. But suppose I have water in a beaker and I read it ...
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### Finding the parameter regime over which a phase transition is observable

Suppose, two variables $P$ and $Q$ follow a relation like, $P=AQ^n$, where $A$ is a constant. If this relation describes the phase diagram of a system obtained numerically, how can I determine the ...
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### What happens when the latent heat of a substance is more than the specific heat capacity of its liquid form?

i came upon a question involving mixing a given of 15 degree celcius water with a given amount of ice, they asked me about the final temperature of mixture... i solved this question by applying the ...
1 vote
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### Phase Equilibrium Conditions

In explaining phase equilibrium, my textbook gives an example of two phases ($\alpha$ and $\beta$) of the same species coexisting together and isolated from the rest of the world. With the total ...
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### Can we always predict the ground state's phase of an unfrustrated quantum model with it's classical approximation?

Let's say, that we want to make a phase diagram of the Heisenberg XXZ model  H = - \left ( J \sum_{\left<i,i'\right>, i < i'} \bar{S}_i \cdot \bar{S}_{i'} + \lambda \sum_{\left<i,i'\...
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### Transverse-field Ising model in the presence of a longitudinal field - ferromagnetic phase diagram

I am wondering what is the phase diagram of the transverse-field Ising model in the presence of a longitudinal field, in particular, a one-dimensional spin-1/2 chain with ferromagnetic interactions. ...
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### Phase difference calculation

I have the frequency of two waves $A$ and $B$ and I want to calculate the phase difference of $A$ relative to $B$ in degrees. I also have the phase difference in terms of time $t$ i.e. the time ...
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1 vote
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### What is beyond the supercritical fluid? [closed]

I always wondered what was beyond the supercritical fluid. At first, I thought there was nothing, but then I thought well there be an ultra-critical fluid. Is there even a phase beyond it?
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### Why does snow disappear without melting?

During very cold weather, snow often gradually disappear without melting.
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### Is the pressure always the same for each phase of a two-phase system?

I am currently reading a textbook called Engineering and Chemical Thermodynamics but I am stuck in one part about the State Postulate and the Gibbs Phase Rule. The Gibbs Phase rule says that the ...
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### Can you go from a gas to a liquid without condensating through supercritical fluids?

If you were to take a gas like co2 and then heat it up and pressurize it in a specific way, would it theoretically be possible to turn the gas to liquid without using condensation? This would be hard ...
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### Why in open container and atmospheric pressure the temperature of water can't be increased more than 373K? [duplicate]

I am a high school student and I am very confused in understanding the phase diagram and boiling. It seems like most people didn't understood the question well may be because I didn't explain the ...
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### Critical Point and Triple Point

Triple Point vs. Critical Point Why is specific volume unchanged at Critical Point but can have a range of values of Triple Point?
157 views

### Difference between stable manifold and basin of attraction?

In 'Nonlinear Dynamics and Chaos' by S. Strogatz, a distinction is made between a stable manifold and basin of attraction of a fixed point in phase space: Here, the stable manifold of a saddle point ...
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### How should I interpret eigenvectors in second quantization?

a) I would like to ask, if knowledge about eigenvectors in second quantization is important and what do they mean? Let's just say, I create Fock space [(NumberOfSites)x(Permutations) matrix], then I ...
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### Why do we use a different value of Quality Factor for different resonance and non-resonance circuits?

In my school , I was taught that Quality Factor(Q.F) = reciprocal of Power Factor(P.F) = impeadance / resistance . But, while solving problems of resonance circuits I found that Q.F = reactance / ...
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### Realistic graphical representation of Thermodynamic Cycles

While studying Thermodynamic Cycles like the Stirling Cycle and the Carnot Cycle, the representation of such Ideal cycles show them to have 4 distinct phases. For example, the Stirling cycle has an ...
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### Maximum temperature of plasma according to $pT$ diagram

When I look at the graph, I can find maximum temperature of plasma (roughly 1eV at 10kPa). But you can get a lot hotter with plasma. Please, where is the mistake? See: or See: https://www....
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### What is a weakly first order phase transition?

I found some articles talking about a weakly first order phase transition; for example this one: https://arxiv.org/abs/2106.15462 I don't get what it is and find no clear sources on the phenomena. So, ...
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### Chemical potential interpretation for QCD phase diagram

I'm studying the QDC phase diagram at finite densities and I'm having some trouble understanding the role of the chemical potential. It's clear how, if I increase the density of particles at $T=0$, I ...
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### Vaporization - phase diagram

I understand what boiling and vaporization is. But what puzzles me is the phase diagram. When I spill a glass of water in my room, it will soon vaporize, though there was normal atmospheric pressure ...
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### Water boiling point at room temperature (30 C) and thermodynamic tables

We all know that water boils at $1\rm\,atm$ at $100°\rm\, C$. But if we maintain the water temperature at $30°\rm\, C$ and instead let the pressure drop (in a vacuum chamber) to around $0.3\rm\, bar$, ...
1 vote
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### What happens to water as it is increasingly compressed?

Imagine we put some volume of water in an infinitely strong container, and then start to slowly exert a force on the top of the water , with increasing pressure. What happens to the water over time? ...
1 vote
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### Why is the subscript $f$ used to refer to properties relating to that of saturated liquid?

In the formula for calculating Vapour Quality, the properties relating to the saturated liquid have a subscript $f$. The properties relating to that of saturated gas have a subscript $g$. I understand ...
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### How can plots showing the mixing line for Schmidt-Appleman criterion (for aircraft contrail formation modeling) show liquid water below triple point?

In trying to understand the Schmidt-Appleman criterion for contrail formation. There is one aspect that I cannot make sense of. In many papers that describe the criterion they include a plot as shown ...
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### How much heat energy is required to bring 1 liter of water to the critical point?

This is not a homework question. The critical point of water is 374 C and 22.06 MPa. At the critical point the latent heat of vaporization is 0 - why? Assume the water starts at 100 C. If you add the ...
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### Where can I find pressure-temperature diagrams or phase diagrams for various substances on the internet ? (and for free)

In this particular case, I want to investigate making liquid nitrogen. My compressor will only go to 400 PSI, so I want to know what temperature nitrogen will turn liquid at 400 PSI (and really 350 ...
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### I don't understand why for resistors in AC circuits the phase angle between voltage and current is zero

From the following graph I understand it is because they reach the voltage and the current reach their maximum values at the same time on the resistor, but I don't understand why this should be that ...
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### Can a liquid forms vapor pressure at 0 degree Celsius? because we know that at freezing point the vapour pressure of both solid and liquid are equal [closed]

How can we able to explain the vapour pressure in between solid and liquid phase in case of freezing point? 