Questions tagged [pressure]
For questions about gas pressure, or the effect of pressure in general on chemical species, substances, or reactions.
309 questions
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In a perfect vacuum, shouldn't every solid be above its sublimation point, since its vapor pressure must exceed the atmospheric pressure?
If the sublimation point of a substance is the point where its equilibrium vapor pressure exceeds the pressure of the atmosphere upon it, and if every solid above absolute zero has some vapor pressure ...
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Is it safe to use borosilicate lab glass as an autoclave?
I'm attempting to do a one-pot synthesis that requires autoclaving the chemical mixture. I thought this process would be greatly simplified by using the lab glass itself as the autoclave in situ ...
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Negative pressure
I am conducting a simulation of a three-layer system consisting of surfactant, water, and oil using GROMACS. As part of the verification of the results, I am outputting the pressure in GROMACS to ...
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Relation between dilution and osmotic pressure
The following question is taken from IAT 2024, an entrance test for research institutes in India at the high school level:
Which one of the following plots correctly describes the variation of ...
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If a pocket of nitrogen gas is pumped in at the bottom intake of a padded tank will the pocket of gas bubble up?
I have a nitrogen gas padded tank (tank 1) which is filled from the bottom of the tank. Tank has a set point of 30 psi which adjusted as tank level changes. Also at the inlet is an additional pipe ...
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Is it possible to achieve pressures of over 1000 GPa in a lab?
In order to simulate pressures inside of a planetary core, we would need pressures over 1000 GPa. I researched diamond anvils, but they seem to only withstand pressures up to 770 GPa in some extreme ...
user145680
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Does a steel pestle corrode while pressing soot?
While experimenting with a few different powders, I noticed the resulting small flakes were ferromagnetic. Then I decided to find out what was the cause: after repeating the experiment with only soot, ...
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Effect of Pressure on the Position of Equilibrium
The following general reaction proceeds with decrease in amount of substance, so increasing pressure should shift the position of equilibrium to the right.
$$\ce{2 A(g) <=> B(g)}$$
But let's say ...
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Does osmotic pressure depend on the quantities of the outer membrane solvent?
$$\pi V = nRT$$
What is the osmotic pressure at $\pu{25^oC}$ of an aqueous solution of 0.0010 M $\ce{C12H22O11}$ (sucrose)?
We just need to substitute the data into equation (13.4)
$$\pi = \frac{\pu{...
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What is the exact definition of isotonic solutions?
Background of the Question
I am a high school student so maybe my understanding of this topic is quite less, so apologies in case I have asked an elementary question.
My chemistry sir taught that :-
...
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Are there materials harder than diamond at high pressure?
It is well known that hardness and Young's modulus can change as a function of pressure. Are there any chemical substances that under sufficiently high pressure exceed the hardness of diamonds at the ...
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Is there such thing as metallic helium?
I know that hydrogen can behave as a conductor under high pressure (metallic hydrogen); however could helium behave similarly under high pressure? If so, could this have any potential benefits over ...
user145192
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Calculating pressure inside a bag using the ideal gas laws
I was doing an experiment to inflate a bag using CO2 produced from a reaction between baking soda and vinegar. I came up with a balanced chemical equation and used the ideal gas law to calculate the ...
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Neglected partial pressures dependence of water splitting
I am studying electrochemical water splitting and I have a huge doubt. The standard redox potential for the total reaction is 1.23 V, but this is in standard conditions, where the hydrogen and oxygen ...
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What happens to pressure when a liquid goes supercritical?
Fill a pressure vessel with water, no airspace. Heat it past 374 Degrees C, so that the water goes supercritical but can't expand. What happens to the pressure at that point? Does it continue to ...
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Why is the relationship between vapour pressure and boiling point of water non-linear?
From my rudimentary understanding of chemistry, pressure should be directly proportional to temperature for a constant mass of gas under the same volume (Charles’s law).
However, in the diagram above,...
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Effects on pressure on reverse electrolysis
I am interested in the effects on pressure of the following reaction.
$$\ce{O2 + 4H+ + 4e- → 2H2O}$$
I have been trying to find data on this for a while, and I am sure that the information exists, but ...
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Validity of ideal gas law for pure species or mixture
I'm currently dealing with an application involving gases. I have pure nitrogen as a pressurizer and eventually water vapour (only if condition for evaporation or boiling are met).
I wanted to ask to ...
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How to treat enthalpy change and pressure in reactions involving a liquid and solid state
In physical chemistry, it is often stated that "at constant pressure, the change in enthalpy gives the amount of heat transferred into the system" and the justification for this claim is
$$...
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If I make CO2 by exposing CaCO3 to HCl, how much of it would be dissolved in the water [closed]
For an experiment we're trying to measure the amount of gas produced in this reaction. But we always find less gas then expected, then a colleague told me that it could be because some of the CO2 ...
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Heat capacity of (ideal) gases at constant pressure
I've come across this article which says that the constant pressure heat capacity is independent of pressure.
It also gives a mathematical explanation which says that any work of an ideal gas at ...
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Is fugacity the corrected pressure that should be used in thermodynamical models?
I am a little confused about fugacity and pressure of a gas. In ideal gases, pressure is same as fugacity. But for real gases this is not the case. Here is the link of the question that is the source ...
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Heat increase after pressure drop in polymer filter
I would like to calculate the heat increase in polymer filter. A polymer filter (mesh size p.ex.20 µm) decreases the mass pressure of the polymer flow.
How it works: The polymer is melted in an ...
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Pressure before equilibrium = Pressure during equilibrium?
For example, let's say we have the equation $$\ce{PCl_3(g) + Cl_2(g) -> PCl_5(g)},$$ and the temperature is held constant.
Would the pressure in the container when equilibrium is reached be greater ...
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Do gas particles colliding with each other affect the overall pressure?
Gas pressure is the pressure exerted by gas particles when they collide with the walls of the container. The gas pressure increases with the number of gas particles.
Does the collision between two gas ...
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Why is there a limit to the amount of water vapor in the air even though the atmosphere is so vast? [closed]
I have read that temperature and pressure dictate how much water vapor can exist in the air.
Air is a mixture, so shouldn’t the addition of water vapor just add to the mixture regardless the ...
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Which way Le Chatelier's principle
I have been pondering about the effect of pressure change in regard to Le Chatelier's principle on reactions. For this, I considered the following reaction:
$$\ce{CO(g) + 3H2(g) <=> CH4(g) + H2O(...
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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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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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Does high pressure reverse reaction between zinc and sulfuric acid?
When zinc is added to sulfuric acid, it undergoes a chemical reaction that generates hydrogen gas and zinc sulfate. Can this reaction be reversed by applying pressure to the products converting them ...
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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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Calculating percentage of Zn in a coin
Question:
An old coin found in an ancient temple is composed of zinc coated with copper. In an experiment to find the percent zinc in the coin, a student determined the weight of the coin to be 3.0 g. ...
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When styrofoam shrinks from pressure, why doesn't it go back to normal after decreasing the pressure?
In this article (https://oceanexplorer.noaa.gov/explorations/16carolina/logs/sep3-2/sep3-2.html) and articles like this one, Styrofoam cups were taken to the depths of the ocean in an AUV to ...
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How does the partial pressure of oxygen relate to its concentration in water?
I've read that the partial pressure of oxygen in water will be the same as the partial pressure of oxygen in the atmosphere, but that the saturation of oxygen in water is dependent on factors like ...
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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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Osmotic pressure for non-electrical neutral region of a solution
For calculation of the osmotic pressure, we can use Van't Hoff equation as below:
π=CRT
If we put the solution in an electrical field, the cations and anions move towards negative and positive pols, ...
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Use the first law of thermodynamics to derive the pressure as a function of T, U, V and N
I am struggling with a thermodynamics question given
$$S(U,V,N)=C_VNK_\mathrm b\ln U/U_0+NK_\mathrm b\ln V/V_0$$ (where $U_0$ and $V_0$ are the reference energies and volumes) and the first law of ...
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How does pressure affect the color of reaction medium with equimolar amounts or reactants and products at equilibrium?
Chlorine gas is pale yellow-green, and both hydrogen and hydrogen chloride are colorless gases. According to the Le Chatelier's principle, the change in pressure will not affect the following ...
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Osmotic Pressure definition clarification
currently reading Legninger's Principles of Biochemistry (8th edition if you absolutely needed to know) and under "Osmotic Pressure" it gives the definition to be:
Osmotic pressure, $\Pi$, [...
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Confusion in Van der Waals Equation
I understand that the behavior of ideal gases deviates largely from that of real gases in terms of pressure exerted by the gas molecules on the container in which it is present, space available for ...
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Effect of Pressure on Equilibrium
This might be a little bit of a basic question, but I've been trying to get my head around pressure and Le Chatelier's principle and I can't quite understand it.
Currently, my understanding of Le ...
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What happens to polymers under high pressure?
What happens when you have polymers under high pressure? My very sketchy thoughts of polymers are that they can be thought of tangles of carbon chains surrounded by hydrogen, but that some polymers ...
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How to calculate vapor pressure of ethanol at given temperature?
The following is a part of the problem I am struggling with. I think what I need is a vapor pressure of ethanol at $\pu{25 °C},$ but I may be totally wrong.
A reactor is charged with $\pu{60 bar}$ of ...
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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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How do fullerenes withstand external pressure from collapsing the molecule?
As Fullerene's have an empty shell inside their structure how they withstand the pressure from the outside?
As a sidetone, are there any methods for calculating the force that the "vacuum" ...
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What causes water to condense when air pressure is reduced?
In this video: https://youtu.be/IyBRGhXBuGw
The cabin pressure is reduced and subsequently a mist is formed.
What exactly is the cause?
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Do solids in a solution also apply partial pressure? If yes, can this be used as an intuitive explanation for osmosis?
I know that in a mixture of different gases, we can assign every type of gas molecules a partial pressure so that the total pressure is the sum of all partial pressures. This can be extended to gas ...
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Ideal Gas Equation Extreme Case [closed]
I have recently learned about the Ideal Gas Equation and I have this doubt.....suppose I am in a closed container filled with a gas of fixed volume and definite amount of moles. I am assuming myself ...
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What would happen if I increase the pressure and temperature of a gas present in a container
Assume the gas to be a real gas and the container to be made of diamond or anything stronger than that. Take the amount of gas to be 2mL and the pressure is increased with the help of strongest ...
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