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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At the freezing point, why is the vapor pressure of the liquid phase equal to the vapor pressure of the solid phase?

At the freezing point of a substance, the solid phase is in dynamic equilibrium with the liquid phase. My textbook defines the freezing point of a substance as: "the temperature at which the vapor ...
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Why is Trouton's rule not valid for liquids with boiling points less than 150 K?

This is a question from the last year's semester examination. Why is Trouton's rule not valid for liquids with boiling points less than 150 K? I searched the internet but only found that the ...
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Is it correct to say that SOME iodine undergoes sublimation at 1 ATM

The triple point of Iodine occurs at 0.12 atm and at standard temperature it is a solid on the phase diagram. I understand that therefore, when heating iodine at 1 atm, it (at least some of it) will ...
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115 views

Determining the amount of water to create a given pressure in a sealed container

I have a sealed container with a volume of 1 liter. I want to go from an initial pressure of $P_{1}=1\ \mathrm{atm}$ and an initial temperature of $T_{1}=298\ \mathrm{K}$ to a final pressure of $P_{2}=...
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Why is Diiron nonacarbonyl so exceptional?

My textbook(NCERT) says: With exception of $\ce{Fe2(CO)9}$, all other metal carbonyls are soluble in hydrocarbon solvents. Weller, M.; Overton, T.; Rourke, J.; Armstrong, F. Inorganic Chemistry, ...
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Relationship between surface area and vapor pressure

How is vapor pressure independent of the surface area and volume of a liquid, although rate of evaporation depends on surface area? Please someone help me I am totally confused.
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Steam Pumpkin Launcher

I am doing a pumpkin launcher project and my group is torn between using an air cannon, trebuchet, centrifugal arm, and a steam cannon. I want to take water fill the tank x % with water and heat it to ...
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Change in volume of two beakers on reaching equilibrium

Two beakers are placed side by side in a sealed container. The first beaker contains 100 ml of pure water. The other an equal volume of an aqueous solution of sugar. What should be the volume of the ...
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will mercury vaporize in boiling water in a flask?

Will mercury vaporize with the water vapours if boiled in a flask full of water? Also if we store mercury under water in the beaker will it still give vapours? If some mercury is bound to vaporize , ...
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vapour pressure above 2 separate beakers containing liquids which form ideal solution

Suppose we have A moles of liquid 1 in one beaker and B moles of liquid 2 in the other. Beakers are placed together in a biger closed container. Both have different vapour pressure when isloated. Now ...
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The effect of pressure on boiling point?

My textbook states the following: Qualitatively, I understand why the boiling point of a substance increases when the pressure is increased. However, I learned that if the pressure is increased when ...
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858 views

Vapour Pressure in Closed Containers [closed]

When the vapor pressure exerted by the gas equals that exerted by the liquid, do their densities equal?
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What is the formula for evaporation rate of water? [closed]

I did my own research, and according to The Engineering Toolbox,the formula for the evaporation rate of water is as follows: $g_\mathrm h = \Theta A (x_\mathrm s - x)$ $g_\mathrm h$ = amount of ...
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Could compressed refrigerant be stored feasibly in residential setting?

In Vapor-compression refrigeration, a refrigerant is compressed releasing heat (typically outside a building) and then decompressed in another location, absorbing heat. A residential air conditioner ...
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970 views

How many litres of water will be sufficient to generate 1600 psi when heated?

Here's my setup. I have a pressure vessel with x liters of water. I'll be heating the water at 320 C. I want to achieve at least 1600 psi of force inside the pressure vessel. So how do I calculate ...
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Why does Raoult's law work? [duplicate]

I am trying to look for the entropy explanation but I do not understand anything I can find. Please keep it simple but talk about it from a entropy point of view. Use water and a volatile solute as an ...
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813 views

Effect of an inert gas on steam vapor pressure at equilibrium

Suppose we have a closed container with mobile walls, so it will change its volume in order to equal the external pressure(constant) to the internal pressure. This container has inside it a liquid ...
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Vapour Pressure and Equilibrium

I found this questions on a YouTube lesson and I'm confused with the answers they have given: "A liquid in its equilibrium with its vapour is in a sealed container at a fixed temperature. The ...
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Heating of mixture of gases with one gas barely above its boiling point

What happens when mixture of two gases is heated in a closed container? If one gas expands faster than the other and increases pressure of the container enough so that the boiling point of the other ...
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Vapor pressure of immiscible liquids

I have read that vapour pressure of a mixture of two immiscible liquids is $$P=P^0_A + P^0_B$$ where A and B are immiscible liquids. If they are immiscible, they would form separate layers. Thus ...
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Control the pressure of Hydrogen in a small container without the use of a pressure regulator

I had recently asked this question, and due to the comments and general consensus of safety concerns, I decided to re-ask the question, attacking the problem from another angle. The Problem I need to ...
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Vapor-pressure or Vapor-concentration

To summarize from my textbook: rate of evaporation: proportional to surface area but essentially independent from pressure (of surrounding gas) rate of condensation proportional to both surface ...
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What is the lowest temperature tungsten starts sublimating at?

What is the lowest temperature tungsten starts sublimating at? I've tried to search in Google but without any luck. For example, $\ce{WO3}$ starts sublimating roughly at $\pu{550 °C}$, according to ...
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How is volatility useful in the production of acids?

Sulfuric acid because of its low volatility can be used to manufacture more volatile acids from their corresponding salts. How does volatility affect the production of acids? Isn't it that sulfuric ...
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Calculating the mass of water removed by air conditioning condensation

I cannot figure out how to calculate the mass. The question is: "Suppose the percent relative humidity is $\mathrm{80.0\%}$ at $\mathrm{91.4\ ^\circ F}$ ($\mathrm{33.0\ ^\circ C}$) in a house ...
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Why don't the solute molecules in a volatile solvent also escape to contribute to vapor pressure?

I'm currently studying relative lowering of vapor pressure with the addition of a solid non volatile solute. The book explains it with the notion that some of the non volatile solute also appears at ...
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Colligative properties

I have some problems with these properties. 1) Lowering vapor pressure and boiling point. It happens because the solute molecules take space in the surface of the liquid so a lower number of the ...
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Vapor Pressure - Sealed Vessel

I have read that vapor pressure is only affected by temperature, but all of the examples have been in a sealed vessel. I have also read that pressure does not affect vapor pressure. I am looking for ...
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Boiling point and vapor pressure

Does a liquid having higher vapor pressure have a lower boiling point? I think so because I read in wikipedia that, "A substance with a high vapor pressure at normal temperatures is often referred to ...
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When water boils at its boiling point how do we call it as an equilibrium?

On boiling, water becomes a vapor, liquid volume decreases and vapour volume increases. Since volumes are not constant, how do we call it as equilibrium?
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Raoult's Law and Mole Fraction

Raoult's Law states that the partial vapor pressure of each component of an ideal mixture of liquids is equal to the vapor pressure of the pure component multiplied by its mole fraction in the mixture....
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1answer
807 views

Rocket propellants: accuracy of vapor pressure estimation techniques

I would like to determine the vapore pressures of a couple of substances (rocket propellants) over a significant temperature range within a ~10% error margin. For a first test, I tried to ...
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What is the connection between vapor pressure and intermolecular force explanations of boiling?

I've had boiling explained to me in two ways, and I'm having trouble understanding how they connect. The first way is that a liquid is held together by the intermolecular forces, and boiling involves ...
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Is menthol an especially volatile molecule?

I have been studying a bit about odors and plant essential oils. Several sources claim that the fragrant terpenes found in these oils, such as menthol, eugenol, limonene, linalool, etc. are volatile ...
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Why does melting point depend on external pressure?

The melting point of a substance is the temperature at which the solid form's vapor pressure equals the liquid form's vapor pressure. I read that the vapor pressure of something depends ONLY on the ...
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What is the mass fraction of C2HCl3 in the liquid phase?

Vapour-liquid equilibrium of a two-component ideal solution of trichloroethene (C2HCl3) and trichloromethane (CHCl3) is established at 25 °C. The mole fraction of CHCl3 in the vapour phase is 1. What ...
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Mass of sugar that was added to the water (Raoult's law)

Water has a vapour pressure of $15.5~\mathrm{mmHg}$ at $25~\mathrm{^\circ C}$. An unknown amount of the non-volatile sugar glucose ($\ce{C6H12O6}$) is added to $1.31~\mathrm{kg}$ of water and the ...
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Calculate the mole fraction of component B in this solution? (partial pressures)

The vapour pressure of a pure liquid solvent A is $\pu{0.80atm}$. When a non volatile substance B is dissolved in the solvent, its vapour pressure drops to $\pu{0.60atm}$. Calculate the mole fraction ...
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Does storing a hygroscopic reagent in a bottle makes it prone to absorb humidity from the air trapped inside?

I've got a full bottle of 99,5% acetone, which I'd really like to keep it as dry as possible, though without using molecular sieves or other dessicants. Once I open the bottle for the first time, use ...
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Is every substance in equilibrium with its vapours?

In one of my previous questions, I got an answer from user Jan: The smell of a compound as we perceive it usually depends on which receptors in the nose will bind the molecule (or not). These ...
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Vapor pressure and boiling point for solutions in open containers

Question 1: If we have an open container which has water in it and is heated. If there is no lid over the container then how can this water ever boil as there will be no vapor pressure created over ...
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Minimum amount of water in pressure cooker

When cooking I would like to know the minimum amount of water I can add to my 6.2 L pressure cooker, worst case, so without any food. At second ring cooking the pressure is 0.8 bar. I assume I need ...
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Why does cooking oil lower the vapor pressure of water?

I added different amounts of oil to different containers with 50mL of water and weighted the containers. Then I heated the containers for 15 minutes in a water bath and weighted again. I noticed that ...
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Total pressure in a chamber calculation

I have a chamber containing two different gases and a liquid which needs to be heated at a certain temperature to bring it to vapor state. I have worked out that we can calculate the total pressure ...
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Relationship between vapour pressure and saturated vapour pressure

I need clarity on saturated vapour pressure in a closed system at equilibrium. How does saturated vapour pressure relate to vapour pressure?
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What happens when heating water in a pressure vessel?

Suppose that I take a pressure vessel that can withstand up to 2000 PSI. Now I fill it with water (not completely, but around 90%) and start to heat it with a direct flame. What I want to know is, ...
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Using vapor mole fraction and pressure to determine liquid mole fraction

I am studying Chemistry by Zumdahl and Zumdahl (9th edition) and I have come across a question in Chapter 11 that I can't figure out the explanation for: Liquid A has vapor pressure x , and liquid B ...
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Is dew and water vapour the same?

Is it possible to say water vapour and dew is the same? I know that the water vapour is the gaseous phase of water. But what is the dew? I just wonder how can I categorised it. Is it the liquid or ...
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The effect of air pressure on the melting point

What is the effect of air pressure on the melting point of a substance? a) No effect b) The melting point increases when the air pressure increases c) The melting point decreases when the air pressure ...
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Unable to comprehend graph of aqueous lithium bromide vapour pressure

$\ce{LiBr}$ $Vp$ chart: http://www.mediafire.com/view/x77zc8wj11gthsj/LiBr_Vp.jpg or http://www.mediafire.com/view/u4dnocvbsf3atmu/Useful_Chart_LiBr.pdf Lecture in question (p.13) http://www....