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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6
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2answers
10k views

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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2answers
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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, ...
2
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1answer
9k views

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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2answers
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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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4answers
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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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0answers
85 views

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....
15
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1answer
494 views

How does composition of air affect vapor saturation limit?

Suppose we hold temperature, pressure, and gas composition (say, a standard atmosphere) constant. Then we know that if we allow the water content of the air to vary it can range between 0 and some ...
6
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2answers
404 views

How can I turn LPG from liquid to gas?

I am working on a personal project that involves a balloon filled with liquefied petroleum gas (LPG) at a pressure of $\pu{4 - 5 bar}$, and I need some kind of a device/filter that would convert it to ...
10
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4answers
13k views

Reason for the formation of azeotropes

Why is it that some liquid mixtures (that exhibit positive/negative deviation from Raoult's law) form azeotropic mixtures at certain compositions? What is the physical reason behind this; are there ...
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1answer
20k views

the chemical mechanism for deviations from Raoult's law

Mixtures of ethanol and acetone have vapor pressures that are higher than predicted by Raoult's law, while mixtures of acetone and water have lower vapor pressures than predicted by Raoult's law. Why ...
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1answer
3k views

Finding Kp at another temp with /\Hrxn [closed]

Took a pic of the paper I tried it on it on, has the exact problem description written at top, and what I tried. Figured that would be easier then typing all that. The answer is supposed to be 2.0.
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1answer
1k views

Applying Raoult's Law to a condensed gas mixture

So, here's the question which I'm having trouble solving : Suppose that we condense a gas mixture. At 25 celsius, what will be the pressure of benzene and of toluene over the obtained liquid. We ...
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0answers
957 views

How are pressure vessels heated?

I'm working on a project in which I'll be dealing with pressure vessels. As of now I've drawn/conceptualized everything on theory basis. The diagrams are made on the basis of theory, but then I came ...
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1answer
82 views

Pressure over a solution

I was wondering something, if I have the same molar fraction for two different substances for a vapor on top of a solution, will this mean that the pressure of each individual substance will be the ...
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2answers
7k views

Why does decreasing the pressure of the system increase the relative volatility of a binary solution?

In our teaching lab, we were posed with the following question as an exersize: If the boiling points of two compounds differ by $\pu{50 ^\circ C}$ at atmospheric pressure, what will be the effect ...
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2answers
2k views

How to calculate the vapor pressure of water?

$48~\mathrm{l}$ of dry $\ce{N2}$ passes through $36~\mathrm{g}$ $\ce{H2O}$ at $300~\mathrm{K}$, and this results in a water loss of $1.20~\mathrm{g}$. The vapor pressure of water is? The solution ...
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1answer
58 views

Is atmospheric pressure acting only on the contents or also on the container?

$22~\mathrm{g}$ of dry ice is placed in an an empty $600~\mathrm{ml}$ closed vessel at $298~\mathrm{K}$. Find the final pressure inside the vessel, if all $\ce{CO2}$ gets evaporated? Now by applying $...
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3answers
864 views

Is this the right conclusion for a thought experiment?

In this thought experiment, let’s consider the surrounding to be air that is composed of entirely water vapor (no other species like $\ce{O2}$ and $\ce{N2}$ are present). The surrounding is infinitely ...
5
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1answer
903 views

Will the water at the bottom of the tube boil at the same temperature as the water at the top of the tube?

Consider a long, vertical tube of water, as shown below: Where $P_\mathrm{atm}$ is the atmospheric pressure and $P_\mathrm{bottom}$ is the pressure at the bottom of the tube. The tube is long ...
17
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2answers
12k views

What causes the lowering of vapour pressure in volatile/nonvolatile solvent mixtures?

"Based on Figure 13.18, you might think that the reason volatile solvent molecules in a solution are less likely to escape to the gas phase, compared to the pure solvent, is that the solute molecules ...
3
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1answer
2k views

How does grease become airborne?

When cooking in the kitchen you usually use some oil or butter to bake your meat and potatoes in. After some weeks without cleaning (which happens every now and then) the surroundings of the stove ...
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2answers
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Can you concentrate alcohol by evaporating the aqueous solution at room temp and collecting on a cold surface?

I have a bowl containing cheap wine and an immersible fish tank heater. The heater warms the wine to 30 deg C. The bowl is located in a large closed bucket, where it sits on a support. The bucket is ...
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1answer
197 views

Understanding Millimeter of Mercury

A Millimeter of Mercury(mmHg) is by definition the pressure exerted on a column of mercury 1 mm in height. I found this definition confusing because it doesn't say how the diameter of the container ...
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1answer
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How does Ostwald-Walker method work?

From searching online I found this: The apparatus consists of two sets of bulbs. The first set of three bulbs is filled with solution to half of their capacity and second set of another three bulbs ...
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1answer
52k views

Volatile and non-volatile solutes in solution

What is the difference between having a volatile versus a non-volatile solute at the boiling point of the solution? I have been getting mixed answers online concerning the differences outlined above. ...
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2answers
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Is sublimation a property of all substances?

I wonder if sublimation can be done only on certain substances like iodine, or it can be done on all substances. In other words, can sublimation be done, for example, on water? If it cannot, then why?...
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4answers
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How to calculate melting/boiling points at different pressures

I know water boils at below room temperature in a vacuum, and want to know if there's an equation to calculate the melting or boiling points of elements or compounds at a given pressure. How would I ...
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1answer
16k views

Liquefying butane in a freezer

If place a can of pressurized liquid butane (such as a lighter refill canister) into a freezer to get it below its boiling point of $-1\ \mathrm{^\circ C}$, and then release it into a container kept ...
0
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1answer
70 views

Clarification on vapor pressure

If I have a glass of water, and the vapor pressure is the point of equilibrium where the liquid molecules are becoming gases and the gas molecules are colliding and becoming liquid at the same rate, ...
3
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1answer
439 views

Condition for formation of azeotropes

Consider a binary azeotropic solution of two volatile components $A, B$. I wanted to try and find out the required concentrations of $A, B$ in the solution in terms of their vapour pressures. I tried ...
0
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2answers
7k views

Which of these solution have the lowest vapor pressure in 298 K? [closed]

Which of these solution have the lowest vapor pressure in 298 K? Please give a brief explanation. 0.01 m $\ce {CaCl2}$ 0.01 m $\ce {NaCl}$ 0.02 m $\ce {NaCl}$ 0.015 m $\ce {CaCl2}$ 0.01 m $\ce {...
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2answers
2k views

How to determine the vapor pressure of a glycerine and propylene glycol mixture?

I am looking to calculate the minimum heat needed to create vapor from a specific mixture. I have a mixture of 60 % $\ce{C3H8O3}$ (glycerine) and 40 % $\ce{C3H8O2} $ (propylene glycol, propane-1,2-...
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1answer
485 views

Does nitrogen pressure in tyres fluctuate to much a lower degree than air with changes in temperature?

This is my first question in this site. I am referring to this question.The linked question what is the advantage of filling nitrogen in bike tubes over air and I got some answers such as: The ...
3
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1answer
3k views

Calculate vapor pressure from volume

For a chemistry lab, I'm required to calculate the vapor pressure of some organic solvents... methanol, ethanol, and propanol, in addition to an "unknown" sample of some solvent. In the lab, we were ...
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1answer
267 views

Partial pressure of water in a submerged balloon

A balloon is half filled with water at sea level ($P = \pu{1 atm}$, $T = \pu{298K}$) such that the partial pressure of water is $\pu{24 mmHg}$. It is then submerged to a point where $P = \pu{2 atm}, ...
2
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1answer
8k views

How to arrange substances in order of increasing vapor pressure?

During the lecture in my chemistry class, my teacher posed the following problem: Arrange in terms of increasing vapor pressure: a) $\pu{0.5m}$ sugar b) $\pu{0.5m} ~ \ce{NaCl}$ c) $\pu{2m}$ ethylene ...
4
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1answer
235 views

Why does the conversion of SO₂ to SO₃ require high pressure?

The conversion of sulfur dioxide to sulfur trioxide in the contact process for the manufacture of sulfuric acid requires the following condition: Temperature: 450 degrees Pressure: 1-2 atm, although ...
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2answers
10k views

If gases turn into liquids under pressure, what does carbon dioxide turn into?

Since there is no liquid state of carbon dioxide, what will carbon dioxide turn into when exposed to high pressure?
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4answers
73k views

General rules for deciding volatility

Given an organic compound, is there any way to decide if it is volatile (or compare volatility--everything is volatile in the end)? Volatility is due to the tendency to evaporate. The conclusion I ...

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