Questions tagged [vapor-pressure]
This is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. Apply this tag to questions involving clarification related to vapor pressure.
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Why don't P graphs contradict Raoult's law graphs?
Our teacher gave us the following question:
1 mole each of liquids A, B are mixed in a piston-type vessel and piston is moved slowly and isothermally. (PA0 = 75 torr and PB0 = 25 Torr)
Find:
(a) ...
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Explanation for Raoults Law
The vapour pressure of pure liquids is independent of quantity of substance.
But when in a solution, the vapour pressure of the components are given by
$$P_A=P^°_AX_A$$$$P_B=P^°_BX_B$$
Since $A-A$, $A-...
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Vapor pressure of a weak acid for a solution of its salt
I need to calculate the vapor pressure of an acid in equilibrium with an aqueous solution of its salt. For example, say I have a solution of 40% potassium formate by mass in water at 50°C. How do I ...
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Effect of pressure on the vapour pressure of a liquid
In a textbook I am referring to, there is a section on the effect of external pressure affecting the vapour pressure of a liquid.
Source: A Textbook Of Physical Chemistry Volume 3 - KL Kapoor - ...
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Why causes the curvature of the line in pressure-composition graph?
I have been studying about liquid solutions and came across these graphs.
From the first graph it is evident that the solution considered has been assumed ideal as there is no deviation from ideal ...
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How can I find vapour properties of a compound molten salt?
I'm carrying out thermal-hydraulic simulations of the Aircraft Reactor Experiment (a nuclear molten salt reactor) based on circulating molten fuel salt: NaF 53 mol%, ZrF4 41 mol%, UF4 6 mol%.
While ...
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How do I go about calculating final temperature of tank draining at saturation?
I am working on calculating pressure in a tank where the fluid is sitting at its vapor pressure. For example, imagine a 12 in diameter 100 L tank of nitrous oxide at room temperature (745 psi vapor ...
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Explaining Vapour Pressure and Evaporation by Chemical Potential
According to the coexistence curves, both gas and liquid phases can only exist when the chemical potential of both phases are equal.
Does this mean above and below the coexistence curve of liquid and ...
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Why does the vapour pressure not depend on the surface area and volume of a liquid?
My teacher said that vapour pressure is independent of the surface area and volume of a liquid. But I think it should be dependent, because surface area is directly proportional to the evaporation ...
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Understanding how evaporation works [closed]
I am struggling to grasp the concept of partial pressure and vapor pressure.
Consider a sealed container filled with water and a bit of air that is sufficiently dry placed in a room of temperature 25 ...
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What happens to the air pressure above water as its heated to and past boiling?
If I put a pressure sensor inside an airtight container half-filled with water, and heat the water, what will the pressure sensor read as the temperature increases? Would it linearly increase (black ...
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Is it easier to produce hydrodynamic cavitation in a liquid close to boiling point?
Cavitation is defined as the process of formation of the vapor phase of a liquid when it is subjected to reduced pressures at constant ambient temperature. Thus, it is the process of boiling in a ...
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How does the Szilard-Einstein refrigerator design evaporate its refrigerant?
In their 1927 patent, Leo Szilard and Albert Einstein use butane as a refrigerant in their non-compressive refrigerator design. In the patent the authors begin the description of the principle of ...
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Why are the vapor pressure of toluene and benzene different?
We learnt to apply Raoult's law for the ideal solutions. When the questions are asked, they tell that the intermolecular forces of toluene and benzene are equal. But in the same question, they provide ...
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what's the difference between gas and vapour? [duplicate]
In the lecture, our teacher said that the significant difference between gas and vapour is we can't liquefy gas just by compressing it but it's not the same in the case of vapour."
So, I'm ...
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The vapour density of $N_2O_4$ at certain temperature is 30.Calculate the percentage of dissociation of $N_2O_4$ at this temperature? [closed]
The vapour density of $N_2O_4$ at certain temperature is 30.Calculate the percentage of dissociation of $N_2O_4$ at this temperature.$\ce{N2O4_{(g)} <=> 2NO2_{(g)}}$?
I am unable to understand ...
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Suitable solvents to dissolve Aluminum Chloride (anhydrous) without generating Hydrochloric Acid (aqueous or gas)
Hypothetically, I have a chemical tank that was brought out of service and the solid deposits at the bottom of the tank primarily contain aluminum chloride. The whole system never sees water, and the ...
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What is the flash point of acetylene?
On episode s10e11 of the show Criminal Minds, a confrontation occurs in a freezer full of acetylene gas. In this confrontation, the main character confidently fires her gun because the freezer was &...
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What is the nature of container when talking about Boiling Point of a Liquid [ Vapour Pressure related ]? [closed]
From what I understand, whenever talking about calculating the value of Vapour Pressure we need to take a closed container as there needs to be an equilibrium established {R evaporation = R ...
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In a liquid-in-glass thermometer, how does the gas pressure over the liquid affect the linearity of measurement?
In a common ethanol thermometer, the space above the alcohol column is filled with nitrogen. It also contains varying amounts of the alcohol in the gas phase.
Source: http://www.aashtoresource.org/...
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Is vapour pressure truly a colligative property?
Colligative properties are generally defined as
A colligative property depends only on the ratio of the number of particles of solute and solvent in the solution, not the identity of the solute.
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Does the boiling point of ammonia hydroxide change with the ratio of water to ammonia?
My kids and I are designing a science experiment and we could use help with the ratio of water to ammonia in an ammonia hydroxide mixture.
A little bit of background:
Initial goal: To convert the ...
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Calculating the amount of water condensed when cooling below the dew point
I've been given the following question:
Calculate the dew point temperature of a 60% humid air at $30^oC$. How much water mass wil condensate out of 1 $m^3$ of such air when the temperature is ...
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Pressure and temperature relation of Novec 1230
I am working on a concept turbine for a school project which operates at low temperature so it's necessary for me to have a pressure temperature relation of this chemical or novec 7100 also is okay.. ...
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Are molecules exchanged between a solid and liquid in equlibrium?
In Vapor-Liquid Equilibrium, it is my understanding that molecules exchange between the gas and liquid continuously; even when no difference in temperature or partial pressure exists.
Regarding Solid-...
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Mathematical models of Vaporization-Condensation dynamics
I am a mathematician now studying an introductory chemistry course.
Consider a liquid in a closed container, at (say) room temperature.
Then some of the liquid will vaporize. Then some of the ...
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Vapor-Liquid Equilibrium and partial pressure of ammonia
I tried searching the forums for a similar question but I do not think it was entirely answered:
Suppose I have a closed system in a container with solvent and a certain concentration of gas, say ...
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How do water vapor molecules push other air molecules away?
I've read that when water vapor enters the atmosphere, the vapor molecules push the oxygen and nitrogen molecules out of the way and occupy their space.
But if water vapor molecules are lighter than ...
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Can vapor pressure be defined for permanent gases?
Vapor pressure of a substance, in a given temperature, is the pressure exerted the vapor in a system where the gaseous and liquid phases of the pure substance are in equilibrium.
But, if for a ...
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How do you derive the boiling point elevation equation using Raoult’s law and Clausius-Clapeyron relation?
I know that Raoult's law is $P_{solution}=X_{solvent}P_{solvent}$
and Clausius-Clapeyron equation is $ln(\frac{P_{2}}{P_{1}})=-\frac{L}{R}(\frac{1}{T_{2}}-\frac{1}{T_{1}})$
But how do you derive the ...
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Saturation of air within isolated system with water and ethanol
I am planning an experiment in an isolated system that contains two droplets.
One droplet is water and the other one is a 40% ethanol-water mixture.
The isolated compartment is filled with air at 20°C....
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Why does Raoult's Law have a weighted sum instead of a direct sum?
I'm fully aware of the various questions asked about Raoult's Law, and I'm asking this after having gone through all of them and not finding a suitable answer to my question.
I have studied, that at a ...
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Interpretation of azeotropes from statistical mechanics derivation
In an earlier posted question titled Reason for the formation of azeotropes, @porphyrin presented an elegant derivation from statistical mechanics to interpret partial pressures for the two components ...
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Saturated vapor and liquid densities (VLC curve) from Helmholtz free energy equation of state
I have been reading about the statistical associating fluid theory (SAFT) which computes the Helmholtz free energy ($A$) from the SAFT EoS (a hell lot of equations) for a molecule of interest, and is ...
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Do benzene and hexane form an ideal solution?
My teacher said that benzene and hexane do not form an ideal solution (with reference to Raoult's law) but did not explain any reason for it.
My approach:
Cyclic hydrocarbons (benzene here) have ...
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Pressure increase in a chamber with 1 ml of water heated to 200 °C [closed]
For safety reasons I want to know how much pressure will be generated in a sealed chamber with $1~\mathrm{ml}$ of water, pure nitrogen at $1.3~\mathrm{bar}$ at $22~\mathrm{^\circ C}$. This chamber ...
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What is the ∆H_vap when temperature of a given liquid is equal to the boiling point of the liquid?
What is the $∆H_{vap}$ when temperature of a given liquid is equal to the boiling point of the liquid?
For the other cases ie (i) T>BP, $∆H_{vap}$ > 0 (ii) T<BP, $∆H_{vap}$ < 0
So what ...
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Is there a vapor pressure equivalent to freezing point?
Vapor pressure is where liquids are breaking off into the gas phase, below the boiling point. So is there a term where solids break off into the liquid phase, below the freezing point? Vapor pressure ...
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Data on Vapour Pressures of Silicone Oils [closed]
I am trying to find specific information on vapour pressure of silicone oils with different viscosities which I have used in some experimental work. Is there a chemical databook where this information ...
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Vapour pressure and boiling [duplicate]
I have come across two definitions for boiling point:
It is the temperature at which a liquid gets vaporised
It is the point where vapour pressure = external pressure
How are they related? How does ...
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Why does boiling occur when vapor pressure equals ambient pressure?
Here is my understanding of the boiling process: pressure of the atmosphere is pressing down on the liquid and this pressure is propagated throughout the liquid. That is, pressure everywhere inside ...
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Some salts lower the vapour pressure of water - do any raise it?
Plain old NaCl salt can slightly lower the vapour pressure of water for a given temperature. Other salts such as CaCl₂ lower the vapour pressure to a larger degree.
Do any salts, or compounds of any ...
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Can different components show different deviations from Raoult's law?
Introduction:
Raoult's law is used to calculate the partial pressures of the vapour phases of volatile components of a solution
Given that there are two components, A and B, in the liquid-liquid ...
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Does the vapor pressure of a substance depend on the presence of other gases?
The Clausius-Clapeyron equation (CC equation) can be used to find the (saturated) vapor pressure of a substance ie. the gas pressure at which the two phases (vapor + liquid or vapor + solid) reach ...
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Variation of vapour pressure with application of external pressure
Many times study of fact that with pressure of a substance only depends on the temperature and nature of the substance recently I study about dew point and bubble point.
Then I came up with this ...
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How to sustain iodine vapor in a big container (V=200 L)?
I am lost in a quest on how to have a big container in which I can have iodine vapor at a known temperature.
We intend send iodine into an air flow, and observe fluorescence of iodine in this flow. ...
user110717
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In an open system, can water vapor escape into the atmosphere before reaching the boiling point? [duplicate]
In a closed system, water vapor would have nowhere to go and atmospheric pressure would not be a factor. It would reach dynamic equilibrium with only water vapor.
But in an open system, I think that ...
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Conditions for a substance to show deliquescent or efflorescent behaviour
I have learnt that deliquescent substances are the ones which absorb moisture from the surroundings and convert them to solution and efflorescent substances are the ones which release moisture into ...
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Why vapor pressure is unaffected by change in atmospheric pressure [duplicate]
I am a high school student and I am very confused in a topic about "vapor pressure of liquid". Why doesn't a change in atmospheric pressure affect vapor pressure? I think intuitively that ...
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What does water saturated oxygen mean? [closed]
What does water saturated oxygen mean in this question:
The vapour pressure of water at 80º C is 355 torr. A 100 ml vessel contained water saturated oxygen at 80º C, the total gas pressure being 760 ...
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