# What is Phase diagrams: Definition and 24 Discussions

For the use of this term in mathematics and physics, see phase portrait and phase space.
A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, volume, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous states) occur and coexist at equilibrium.

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1. ### How to calculate the transition temperature in this problem?

Summary: The transition Sn(s, gray) ⇌ Sn(s, white) is in equilibrium at 18°C and 1 atm pressure. If ΔS = 8.811K mol for the transition at 18°C and if the densities are 5.75 g/cm3 for gray tin and 7.28 g/cm3 for white tin, calculate the transition temperature under 100 atm pressure The...
2. ### Phase diagrams for fractional distillation

https://www.chemguide.co.uk/physical/phaseeqia/idealpd.html#top I learned about phase diagrams involving partial Vapour composition, temperature and composition of binary solutions from this website. You can find it if you scroll down to a little above the end First it considers a binary...
3. ### Liquid-solid phase composition: Binary phase diagrams

In binary phase diagram, We draw a tie line to know the composition of the liquid phase or the solid phase. Where the tie line is just a horizontal line. The question is why doesn't the liquid or solid phase composition change as you change the general composition of the alloy? Why does the...
4. ### Phase Diagrams at Very Low Concentration of one Component

What happens to one of the components when it is at VERY low concentration in a two component alloy? My problem: Uranium decays to thorium. The thorium isotopes it decays to typically have pretty short half lives. During casting, it is well known that thorium fractionates to the slag, crucible...
5. ### Why does arsenic sublimate, while gallium melts?

What does it tell you about a substance? A hight melting and boiling point means that the molecules hold together strongly, as in tungsten. A low melting point, as in hydrogen, means they're kinda loose. But what does the distance between them tell you? Something something entropy yadda yadda...
6. ### How can water be boiled without using heat?

Hey everyone, I found this video on Youtube of this guy boiling water by reducing the pressure: I'm not sure how the gauge he's looking at works but I think this is the vacuum instrument he's using: https://us.vwr.com/store/catalog/product.jsp?product_id=4789427 ^It says that it provides...
7. ### What is the definition of phase lag and phase difference?

what is the definition of phase lag and phase difference in waves and how are these 2 related?please explain in simple words and with real life examples. Please explain phase,phase lag and phase difference from scratch.
8. ### Zone refining and phase diagrams

Homework Statement From Ashby's "Engineering Materials"[/B] Homework Equations k=C_o/C_s=m_1/m_2 The Attempt at a Solution Solving for k m_1=(660-548)/(0-32)=-3.5 m_2=(660-548)/(0-7)=-16 k=m_1/m_2=0.219 C_s=C_o*(1-(1-0.219)exp(-xL/0.219))How do I proceed from there? Also, how do I...
9. ### Classify the fixed points of this dynamical system

Homework Statement $$\dot{x_1}=x_2-x_2^3,~~~~~~\dot{x_2}=-x_1-3x_2^2+x_1^2x_2+x_2$$ I need help in determining the type and stability of the fixed points in this system. Homework Equations The Jordan Normal Form[/B] Let A be a 2x2 matrix, then there exists a real and non singular matrix M...
10. ### A more complicated question on lipid phase diagrams

Homework Statement Homework Equations None. The Attempt at a Solution This is the final part of a past exam question. I've got through the first parts and can (thanks to a separate question I asked here) read the phase diagrams and find melting points etc. However now it's asking for...
11. ### Looking for Phase Diagrams for Mag-Thor alloys

I am looking for phase diagrams for Mag-Thor alloys and would also like to get some information on how they are typically processed. Are these alloys typically made by diffusion of Th in the Mg and then thermally homogenized? Or are they usually cast? Perhaps made by some other process all...
12. ### I don't understand the concept of phase diagrams?

Let's use the material brass as an example. My problem is that I have no understanding of the concept of "phases". In the phase diagram for brass, we have α, β, γ, δ, ε, and η phases as well as the liquid phase (L). My question is, how do I interpret these phases? What is the difference...
13. ### Understanding Phase Diagrams: Boiling, Melting & Critical Points

Homework Statement https://scontent-b-dfw.xx.fbcdn.net/hphotos-prn1/v/1012733_10201076259690370_236735593_n.jpg?oh=4896ca67a34d3b223b764aba8ed308ab&oe=528A1B57 Homework Equations http://upload.wikimedia.org/wikipedia/commons/3/34/Phase-diag2.svg The Attempt at a Solution Not sure entirely...
14. ### What is the relationship between equilibrium constant and phase diagrams?

On a phase diagram, the lines are "lines of equilibrium", i.e. at any point on these lines of equilibrium there is an established equilibrium between the two phases on either side of the line. The equilibrium constant is a function of temperature and pressure, and the various other thermodynamic...
15. ### Confused on phase diagrams for binary systems (thermodynamics)

I'm confused regarding the phase diagrams of binary systems. Let's suppose we mix 2 liquids, A and B at a given pressure P that won't change during the whole experiment. I raise the temperature until I observe that some of the mix of liquids vaporizes. What boggles me is that it seems I can...
16. ### Thermodynamics - Help me understand phase diagrams

Homework Statement So my thermo professor has been putting a huge emphasis on phase diagrams, which I didn't really expect. He basically skips most of the analytical/calculus type problems and gives us the graphical phase diagram/ "real world" type of problems for homework. I don't...
17. ### Statistical Mechanics: Phase Diagrams and Effusion

Homework Statement There are two problems: The first problem is to calculate the slope of a phase-equilibrium line of a substance given its properties (Helium, Water, etc.) as the temperature approaches a certain value (in this case, T approaches zero). The second problem is the effusion of...
18. ### Binary phase diagrams - understanding the eutectic point

1) So, does the binary phase always represent the materials 100% on each end? That is to say, if you have lead and antimony, the right side will always represent 100% of one of the two, and the other side will present 100% of the other. If we look in the middle of the diagram, it's 50-50%...

20. ### Plotting Phase Diagrams (Temperature vs Composition)

I'm planning to plot phase diagrams of Temperature vs Composition. I found the formula ln(x) = \frac{\Delta H}{R} (\frac{1}{T_A} - \frac{1}{T}) from the Clapeyron equation. Its a ideal solution of 2 metals in L state and regular solution in S state. Eutectic temperature is at 850C and enthalpy...
21. ### Where Can I Find Phase Diagrams for Substances Other Than Water or CO2?

Where can I find phase diagrams for things other than water or CO2? I'm looking for pressure/temperature ones.
22. ### Convoolution of phase diagrams

Can anyone explain how the convolution and deconvolution of phase diagrams are described?
23. ### Help in mathematical modelling phase diagrams

Help in mathematical modelling phase diagrams! :( Mathematical modelling question on predator-prey models logistic prey-predator model with prey logistic growth dx/dt= ax - bx^2 -cy dy/dt= -ey + fxy ax = growth rate of prey in the absence of predation -cxy = the death rate per...
24. ### What is the relationship between density and phase diagrams?

Homework Statement "Which is the denser phase, monoclinic or rhombic sulfur? Homework Equations Density = Mass/Volume... The Attempt at a Solution How can you tell density from a phase diagram?? Thanks! =) -Megan