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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88 views

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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378 views

Does Langmuir model predict evaporation rates?

Slide #16 of this presentation on amalgams says that "Langmuir's equation" provides a specific "theoretical maximum evaporation rate" for liquid Hg as a function of temperature and surface area. The ...
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When boiling a liquid, how vapour pressure and ambient pressure get equal? [duplicate]

When boiling a liquid, how vapour pressure and ambient pressure get equal? As vapour pressure will increase, it will lead to increase in ambient pressure also. let, Initially there would be some ...
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Acetic acid odor while testing CO2 sensor; can it be easily removed, is there a better way?

A friend asked me to help test a hobby-quality $\ce{CO2}$ sensor MG-811 (updated link). It uses a solid electrolyte and should provide a sensitivity of something like -40 mV per decade. I though I'd ...
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Vapor Pressure, Equillibrium, and Increasing Pressure

I'm trying to make sure my understanding of vapor pressure and transients is correct. Let's assume I have a thermally-controlled sealed environment which started out as the regular air (i.e. ...
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303 views

A chamber to control concentration of a vapor: Is there a name for this equipment?

Mechanical engineer here so please excuse me if my question seems dumb to you! I want to have a chamber $(\approx 40 \times 30 \times \pu{30 cm})$ to control concentration $(\pu{ppm})$ of a flammable ...
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Inquiry of the Changing of Canned Liquid’s State [closed]

Could you heat a can of water to 212 degrees Fahrenheit but stay below the aluminum or the can’s metal’s melting point. Either through putting the can in boiling water or heating it up. Would it be ...
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What is the relation between pressure and chemical potential?

I know that in a two-component gas-liquid system (for simplicity) the chemical potential $\mu_i$ ($i=1,2$) and total pressure $p$ can be defined by $$\mu_i=\left(\frac{\partial U}{\partial N_i}\right)...
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Is my proof valid for the formula of elevation in boiling point? [closed]

Is my proof valid for the formula of elevation in boiling point? proof By Clausius clayperon equation, $$\ln(P)=-\frac{∆H_v}{RT}+c$$ Differentiating, $$\frac{dP}{...
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Why does only a single azeotropic composition exist for a mixture of two given substances?

In the image below, which represents a generic composition vs. temperature plot for a mixture, there is a single intersection point between the vapor and liquid curves. This is due to the fact that ...
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How can I calculate the concentration of ethanol vapor in an airstream?

How can I calculate the concentration of ethanol vapor in an airstream? The steady state generation flow rate (of the vapor) is 625 ft^3/min. The ambient temp is 50-60 F (we can use avg temp 55 F). ...
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When heat is increased, does water move upward in a straw due to increased capillary action or increased pressure?

I left a water bottle with an internal straw in my car throughout a long, hot day. When I opened the bottle at the end of the day, water immediately splashed out from the straw. This made me wonder if ...
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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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473 views

Bromine monochloride equilibrium

The value of $K_p$ for the reaction $$\ce{Br2(l) + Cl2(g) <=> 2BrCl(g)}$$ is $\pu{1 atm}$. At equilibrium in a closed container partial pressure of $\ce{BrCl}$ gas is $\pu{0.1 atm}$ and at ...
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Metals Vapor Pressure [duplicate]

I know metals like copper, silver and gold for example have vapor pressures at high temperature but do their vapor pressures still exist at standard temperatures (290 kelvin) and pressures (100 ...
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982 views

Solution to Raoult's Law for a volatile binary solution (no pun intended)

Raoult's Law In a closed container, $$P_A=P_A^\circ x_A$$ where $P_A$ is the pressure of compound in gaseous phase, and $x_A$ is the mole fraction of the liquid component A in the liquid mixture. If ...
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Predicting the vapor pressure of water ammonia solution

I am working on a project that involves the compressors for a vapor compression refrigeration cycle of R717 (ammonia) and came across something that has been boggling my mind a little bit for no good ...
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What would be the vapor pressure of water at above 100 degrees Celsius?

Water boils when it's vapor pressure equals atmospheric pressure (i.e., 760 mm of Hg) which is at 100 degrees Celsius. If the temperature is further increased, would the vapor pressure also increase ...
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Alternative to mercury bubbler for increasing boiling temp?

A common reaction for forming the octachlorodirhenate(III) anion is to heat tert-n-butylammonium perrhenate in benzoyl chloride at 209 ºC. If you look up the info for benzoyl chloride, one sees that ...
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Vapor Pressure Paradox

This is quite an interesting situation I had thought of. Consider two beakers, each containing $\pu{180 g}$ of water. Also, suppose one of the two has $\pu{1.8 g}$ of glucose dissolved in it. Let's ...
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674 views

Water vapor equilibrium calculations

The question had two parts. The first part said: Calculate the amount of water required to saturate a vessel of volume 82 L at 300 K given that the vapor pressure of water is 38 torr at 300 K. The ...
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Chemically generating a high vacuum?

Suppose I fill a vacuum chamber with 99% oxygen, then pull a vacuum on it down to 10 pascal absolute. If I then vaporize aluminum (for vapor deposition), will the aluminum bind with the remaining ...
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Help me proving Dalton's law of partial pressure formula

How do I prove $${{\displaystyle p_{i}=p_{\text{total}}y_{i}}}$$ where $y_i$ is the mole fraction of the $i^{th}$ component in the total mixture of $n$ components ? Here is what I know ...
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What is the temperature of evaporating water (not boiling)?

The vapor pressure of water at $\pu{70 ^\circ C}$ is $\pu{233.7torr}$. If I were to put a temperature probe directly above the liquid water, what would it read? In other words, does a water molecule ...
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Positive deviation from ideal behaviour [closed]

I am confused about Positive behaviour from ideal behaviour as to why it occurs. 1) Molecular attractions plays a dominant role in positive deviation OR 2) Molecular volume plays dominant role in ...
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Why doesn't the vapor pressure of water depend on the humidity?

Correct me if I'm wrong, I'd like to think of vapor pressure of water as the number of water molecules escaping from the water surface per unit area. Greater the leaving number, greater the vapor ...
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Is vapour pressure of a liquid solution constant at a given temperature, no matter the size of closed container and amount of liquid taken?

Does vapour pressure of a liquid solution depend on the size of closed container, amount of solution taken, given that, temperature is kept constant? Or will it change, if some extra gas is added to ...
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Rate of evaporation of mercury

A restorer of antique barometers reported in a blog post that he has had a barometer on his wall that has shown no "visible" loss of mercury in 15 years. I was kind of curious about this, wondering ...
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Is using melting/boiling point good to measure volatility?

I wanted to figure out a way to compare volatility in organic compounds, so I read on many forums on the differing ways to measure volatility, which included enthalpy of vaporization and melting/...
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Vapour pressure and equilibrium constant

Consider a case I where I have a container halfway filled with a pure volatile solvent. Now we know that liquid molecules will start getting converted into vapour phase, and then dynamic equilibrium ...
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83 views

Why does the crystal sublime more quickly at the corners where there is a higher vapour gradient?

The crystal responds to the larger vapor gradients near the edges by sublimating faster there and thus rounding the crystal. J. Nelson, J. Atmos. Sci., 1998, 55, 910-119. The change in shape ...
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Why don't minerals evaporate from seawater along with the water? [duplicate]

When water evaporates from the ocean, of course the minerals such as salt remain in the ocean-- that's why seawater is so saline. However, I'm very puzzled: why don't minerals evaporate along with the ...
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343 views

Does benzene vapor react with air in a closed barrel?

If we would have benzene in a closed barrel for quite a while at room temperature, some vapor would form fast due to its volatility, right? But let's say that when the barrel was closed, some air got ...
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What is the difference between volatility and evaporation?

I've been trying to find the difference between volatility and evaporation and I can see almost everywhere that the volatility is the tendency of a substance to vaporize. So Q1: what makes the ...
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Osmotic pressure of a solution of a protein?

A small protein molecule, code-named "sloth", has a MM of $\mathrm{1.50 x 10^4}$ g/mol. What is the osmotic pressure exerted at $\mathrm{24.0^oC}$ by 25.0 mL of an aqueous solution that contains $\...
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how to determine the volatility of an organic compound using the physical properties of organic molecules

How do you tell if a compound has a high volatility? Also can the boiling point of a compound be taken into consideration when determining if a compound has a high volatility?
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If some particles of liquid in a solution convert to vapour then why can't some liquid particles convert to solid?

I was reading about the vaporisation of liquid when I came across the following statement. The average energy of the particles in a liquid is governed by the temperature. The higher the ...
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Vapor pressure lowering

I have got this problem in my text book, Consider these three mercury manometers. One of them has 1 mL of water placed on top of the mercury, another has 1 mL of a 1 m urea solution placed ...
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Identifying T1 and T2 in the Claperyon equation

Is there a way to identify T1 and T2 in the two point form of the claperyon equation? I suspect that the greater temperature is T1 and the smaller temperature is T2.
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how to find pressure of a liquid when given volume (1 and 2) and one pressure?

A 5 mL sample of an unknown liquid is placed into a 250 mL flask that has had all of the air removed. The pressure measured in the flask is found to be 35.4kPa. In a seperate trial the student puts ...
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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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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 ...