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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What's the effect of Pressure change in Chemical Equilibrium if any reactant or product is Solid or Liquid?
I am studying Le Chatelier's Principle of Chemical Equilibrium. I am trying to solve a problem involving the effect of a pressure change on a chemical equilibrium.
I know that if a reversible reaction ...
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Why is gas pressure measured in mmHg?
Pressure can be measured in $\pu{mmHg}$ which is equal to the pressure exerted by a “column of mercury” of a height expressed in $\pu{mm},$ at $\pu{0 °C}$ under Earth’s normal gravity.
Does the ...
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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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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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How does hydraulic equilibrium work on the particulate level?
I recently learned that osmosis occurs when there is a semipermeable membrane between pure water and a solution of water. The pure water then fills up the solution's side until, as my textbook put it,
...
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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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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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What happened to this 10 year old unopened plastic bottle?
A colleague of mine found this unopened Aquarius bottle (non-carbonated drink) that was 10 years past its expiration date.
The bottle was collapsed inward which would suggest that the pressure in ...
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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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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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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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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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Will the total equilibrium pressure increase in gas phase reaction PCl5(g) ⇌ PCl3(g) + Cl2(g) after chlorine is removed?
Will the total pressure be greater than the initial equilibrium pressure if all $\ce{Cl2}$ is removed and the following reaction is allowed to re-equilibrate?
$$\ce{PCl5(g) <=> PCl3(g) + Cl2(g)}$...
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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 ...
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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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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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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 ...
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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 the closed container, the amount of solution taken, given that, the temperature is kept constant? Or will it change if some extra gas is ...
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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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Will supercritical nitrogen stay supercritical if we raise temperature and pressure high above critical values?
Nitrogen's critical temperature is -146.96 °C and critical pressure 33.96 bar. If we maintain nitrogen at 220 bar and 400 °C, what will be the state of $\ce{N2}$? Will it be still supercritical? I ...
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Mass of oxygen in He+O2 mixture
A sample of $\pu{1.42 g}$ of helium and an unweighted quantity of oxygen gas are mixed in a flask at room temperature. The partial pressure of helium in the flask is $\pu{42.5 torr}$, and partial ...
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Room-conditions supercritical fluids?
Are there any reasonably obtainable supercritical fluids that I could, say, run my hand through? Wikipedia makes it sound like there are plenty of room-temperature ones, but no room-pressure fluids.
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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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Entropy as the driving force for osmosis
How is entropy responsible for osmosis and is movement of solvent possible from its higher concentration to lower concentration?
By concentration, I will be referring to the concentration of solvent ...
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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
$$...
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Which pressure is used for calculation of standard enthalpy change of the reaction with two or more gases?
Standard state conditions for standard Gibbs free energy change stipulate (among other conditions) that the partial pressure of each gas is $\pu{1 bar},$ e.g. for the reaction
$$\ce{2 A(g) + 3 B(g) &...
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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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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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Henry's law and O2 concentration in alveoli blood
Can Henry's law be applied to find $\ce{[O2]}$ in alveoli blood? This kind of question appeared in an another forum and I've been struggling to find a definitive answer. My initial thought was 'no', ...
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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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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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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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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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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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Pressure vs volume plot for real gas and ideal gas
Background
Recently I have been studying about the states of matter and came to the topic of ideal gases and real gases, and the laws related to them. While studying it from my textbook, I saw the ...
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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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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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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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