All Questions
Tagged with equilibrium phase
39
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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 ...
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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 ...
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3
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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 ...
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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 ...
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2
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Phase equilibrium & phase diagram [closed]
Q) Why does phase equilibrium/inter-conversion ONLY occur at boundary lines between phases in phase diagrams?
Example: According to water phase diagram, at 200 C and 200 atm ONLY liquid water ...
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3
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3
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578
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What does the state of a substance at a specific T and P mean?
From the phase diagram of water, we see that water is a liquid at 20 °C, 1 atm. The state of the water at 20 °C, 1 atm is liquid. But there is actually also water vapor in equilibrium with liquid ...
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2
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Is ionisation an equilibrium process?
I read in a page that ionisation is an irreversible process. But, as equilibrium is always reversible would that mean equilibrium does not involve ionisation process.
And than dissociation is a ...
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2
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Triple Point of a compound and critical point
Is it necessary for all compounds to have a triple point? Also, how is the triple point determined?
Suppose a substance does not have a triple point, so how do researchers agree on the impossibility ...
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Understanding Pourbaix diagram
I am recently taking courses in environmental chemistry and I was introduced to Pourbaix diagram. I was taught that the lines in the Pourbaix diagrams are equilibrium lines. Lets take as an example ...
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Equilibrium for the synthesis of methanol
Liquid methanol is obtained with carbon monoxide gas and hydrogen gas in a reactor at $\pu{300 °C}$ and $\pu{250 atm}.$ $K_p = \pu{9.28E-3}.$ Find $K_c.$
With only these data, do I have to use the ...
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Working out energies of hydrogen bonds by comparing chemical potential of vapour and condensed phase - equation derivation
I want to ask a question about working out the energy of a hydrogen bond between two water molecules, $w_{AA}$ using the chemical potentials of vapour and condensed phases.
I was reading K. Dill, ...
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Is the active mass of every solid and liquid taken to be unity?
I learnt from my textbook and the question/answer - Why is active mass of a pure solid or liquid always taken as unity? that active mass of a solid or liquid is taken to be unity as:
$$[A]=\frac n V=\...
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How is a phase equilibrium defined for a one-component system?
A question on this site asked whether a one-component system is at equilibrium when melting or boiling, and the disparate answers were somewhat dependent on the definition of phase equilibrium. ...
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melting and boiling ...really equilibrium? [closed]
Why are melting and boiling considered equilibrium processes even though the amount (concentration) of both phases keep changing i.e from solid to liquid and so on?
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Cases when Raoult's law is unsolvable
Setup
Consider a closed binary mixture of known total molar composition $n_i$, held at volume $V$ and temperature $T$. The equilibrium phase composition is determined by $\mu_i^{vap} = \mu_i^{liq}$. ...
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Is it possible to have only liquid in a closed container?
I recently read an answer by Aman Rusia for this question: Is a liquid in a container always in equilibrium with its vapour?
In it, they say that
You can't have a container filled with only ...
- 2,109
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Freezing point of solution
It's stated in my textbook that at the freezing point, the vapour pressure of the solid phase equals the vapour pressure of the liquid phase. In a mixture, since the vapour pressure of the solution is ...
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Is liquid water in equilibrium with water vapor at room temperature?
This question was inspired by Why does liquid water form when we exhale on a mirror?.
This question is different from Why does water evaporate at room temperature? because it asks about whether an ...
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1
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Water vapour pressure in oxygen gas bubble
Suppose we have a source of O$_2$ bubble formation in water at specific nucleation sites, how can we estimate the water vapour pressure inside the O$_2$ bubbles?
I know that:
(1): $p_\mathrm{O_2}+...
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222
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How to without calculations understand the liquid-liquid extraction efficiency?
I'm asking myself this question for a very long time and I haven't found a simple an good explanation yet for the fact that it's better (if you want to clean them) to wash your hands two times with ...
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Why are temperature and pressure represented as the number 2 in Gibbs' Phase Rule?
In our class we are learning about Gibbs' Phase Rule; $F=C-P+2$, in which $F$ stands for degree of freedom, $C$ for number of components, and $P$ for number of phases in the system. Our professor told ...
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What causes both components of a binary gas mix to condensate at the same time for a given composition
Okay, so recently I encountered the temperature - mole fraction diagrams for binary vapour-liquid equilibrium. For now, I only consider two-component systems where the components are very similar and ...
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If melting points and freezing points are the same, what state is pure equilibrium?
If melting points and freezing points are the same, what state is pure equilibrium?
I understand melting points and freezing points are the same; adding or removing temperature of melting points for ...
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953
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Effect of pressure on the freezing temperature of water
A few lines are written in a book by B.H. Mahan regarding the change in freezing point of water on changing the pressure.
The vapor pressure of water at triple point of water is 4.579 mm. What ...
user50247
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1
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Does aqueous component contribute to the equilibrium constant?
Consider an equilibrium reaction with an aqueous solution $\ce{A(aq)}$ in equilibrium phase with gas:
$$\ce{A(aq) + B(g) <=>[$K_\mathrm{eq}$] C(g)}$$
Would the equilibrium constant have aqueous ...
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3
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470
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Clausius–Clapeyron relation for states of water and vapor
I've seen many questions about this topic on this site, but I still have some issues trying to understand this aspect. Here's what I believe I understood
looking at the phase diagram for a pure ...
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0
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Equilibrium involving water and solid component
$$\ce{A + B <=> C(s) + H2O(l)}$$
Why when $\ce{H2O}$ is liquid and $\ce{C}$ is solid, the equilibrium constant of the reaction is
$$K_\mathrm{eq} = \frac{1}{[\ce{A}][\ce{B}]} \quad ?$$
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221
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Anhydrous ammonia vapor-liquid equilibrium
I have been given a anhydrous ammonia vapor liquid system in an air-tight container where the pressure is 30 bar and the temperature is 30 degrees. They claim the system is in equilibrium, which I ...
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670
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How to measure chemical potential
I wonder if there is a way to measure the chemical potential of a substance in a two-component mixture and also to account for its dependence on the number of moles. Explaining it further, suppose ...
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Proof of Dynamic Nature of Equilibrium
Here is how my textbook proves that dissolution of solid in liquid is dynamic in nature. It considers the example of a saturated solution of sugar. It says that,
Though the solution is in ...
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679
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Are allotropes of sulfur two different phases?
Monoclinic sulfur and rhombic sulfur are two allotropes of sulfur. In phase equilibria, part of the system that is having distinct boundary, mechanically separable and different chemical or physical ...
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Phase Diagrams and Equilibrium
In this link
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch14/phase.php
It says (in the latter part ) that for all combinations of Pressure and Temperature along line BC
the rate of ...
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Effects of inert gas on heterogenous equilibrium
What is the effect of the presence of an inert gas on a reversible reaction that was in more than one phase, such as a decomposition reaction? If a solid or liquid or compound in aqueous solution ...
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For homogeneous equilibrium, why are liquids and solids included in the equilibrium constant (when they aren't in heterogeneous equilibria)?
In a heterogeneous reaction (where the states are varied) we do not include liquids and solids in the equilibrium equation because their concentrations do not change.
E.g. Chemguide.co.uk
However, ...
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3 component (ternary) system in equilibrium
If the components of a system were Cl2, Br2, and I2, how could I describe this system under equilibrium conditions when the number of phases is at a maximum?
If there are 3 components, using the ...
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Equilibrium saturation/depostion rate calculation
I found the Knudsen/Langmuir equation for calculating the sublimation rate of a solid. If I have a closed system, once the vapor reaches the saturation pressure, the solid will continue sublimating ...
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'Chemical' First-order Phase Change
First order phase changes occur when one local minima of the Gibbs Free Energy becomes deeper than another. Thus at 1 atm and 99 °C, the Gibbs Free Energy of liquid water is less than the Gibbs Free ...
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Why is carbon dioxide gas used in soda?
Why is carbon dioxide used in soda? What makes it preferable to other gases for this purpose?
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How to find and use the Clausius-Clapeyron equation
I know how to get the equation from the Clapeyron equation but I have a question regarding a the integration along a phase boundary and a small step in the derivation that I will make clear when I ...
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