Questions tagged [pressure]
For questions about gas pressure, or the effect of pressure in general on chemical species, substances, or reactions.
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Mass Transfer- Film Theory and Membrane Separation [closed]
There's a question that I've been stuck on for quite some time- can someone help me out?
A polymer membrane which is permeable to oxygen but impermeable to nitrogen is available. It is desired to use ...
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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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Density and partial pressure [closed]
A sample of $\ce{NOBr}$ gas was placed in a rigid flask where it decomposes at $\pu{25 ^\circ C}$ according to the following reaction:
$$\ce{2NOBr(g) <=> 2NO(g) + Br2(g)}$$
At equilibrium, the ...
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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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What's the equilibrium pressure of CO2 gas over sodium hydroxide?
Many (too many) decades ago in physical chemistry lessons, I seem to recall that given the enthalpy changes of reactions, and maybe phase diagrams, one could work out what equilibrium a reaction would ...
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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 ...
user112102
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Why does van der Waals' equation of state give only one P, V pair for a particular temperature here?
I came across this question which I initially ignored believing that the data was insufficient:
Calculate the pressure exerted by one mole of $\ce{CO2}$ gas at $\pu{273 K}$ if the van der Waals' ...
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Molecular orbitals energy under pressure
Suppose we have a hydrogen molecule $\ce{H2}.$ At room temperature the average distance of the nuclei is $r_0$ (without applying pressure).
If we put $n$ hydrogen molecules in a box with volume $V_\...
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Why does CO2 diffuse out of a cylinder in the absence of a pressure difference?
Suppose I have a thermally insulated cylinder containing carbon dioxide (assuming it is ideal) at 1 atm pressure(atmospheric pressure is 1 atm). Now let's consider two cases:
CASE-1: I cut open the ...
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How to calculate Kp without knowing the volume? [closed]
I have the following chemical equation:
$$\ce{Sb2S3 + 3H2 <=> 2 Sb + 3H2S}$$
I have $\pu{1000 grams}$ of $\ce{Sb2S3}$ that reacts with $\pu{10 grams}$ of $\ce{H2}$ in a reactor at $\pu{713 K}$.
...
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Does pressure affect pH? [closed]
Since pH is the function of $\ce{H+}$ ion concentration, the change in volume will change the equilibrium according to Le Chatelier's principle and affect the pH. Is it correct, or are there any ...
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Heat released at constant pressure and temperature and heat released at constant density and temperature
Is there a relation between heat released at constant pressure and temperature and heat released at constant density and temperature?
I was reading some books on propulsion and combustion, and the ...
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Effect of addition of inert gas on concentration in an equilibrium [duplicate]
We have the following equilibrium established in a container with movable piston at atmospheric pressure.
$$\ce{N_2 (g) + 3 H2 (g) ⇌ 2NH_3 (g)}$$
Now how does the concentration of the reacting species ...
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Vapor Pressure of reaction mass undergoing an exothermic reaction
A vessel containing a reaction mass under going an exothermic reaction is under vacuum, with temperature and pressure constant. When the source of vacuum is closed, the reactor begins to increase ...
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When does a piston stop in an irreversible process?
Suppose we have an ideal gas filled inside a container fitted with a piston. The external pressure is equal to internal pressure.
If we suddenly decrease the external pressure, we say that the gas ...
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Pressure of two flasks connected to each other at different temperatures [closed]
Two flasks of equal volume connected by a narrow tube (of negligible volume) are at $\pu{27 °C}$ and contain $\pu{0.7 mol}$ of $\ce{H2}$ at $\pu{0.5 atm}$. If one of the flasks is then immersed into a ...
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Relative humidity and vapor-pressure in equilibrium
I have quite an unclear understanding of relative humidity. I am writing my understanding on the topic and please correct me wherever I'm wrong:
What I understood:
Let's say $\ce{H2O}$ has a (...
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Osmotic Pressure of Aqueous Solution
The osmotic pressure of an aqueous solution at $25$ Celsius is $92.0$ $kPa$. Calculate the boiling point
of the solution. (Assume that the density of the solution is $1.0$ $g/mL$, ignore the mass of ...
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Dissolution of CO2 in water
The following question has troubled me for a while.
For gases that are slightly soluble in water, there is a proportional relationship between the partial
pressure, $P$, and the mole fraction, $x$, ...
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Liquifying a gas above critical temperature [duplicate]
Is there any theoretical/hypothetical way through which a gas can be liquified above critical temperature? For example applying inifinjte amount of pressure to the system?
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