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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Work done on a container, resulting in pressure change

Why does pumping gas into a rigid container (causing the pressure and temperature to increase), not mean that work has been done on the container? Work is given by the formula : W = -P ΔV If I go ...
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How much pressure does Gallium exert when it freezes?

Assuming the liquid Gallium is in a sealed container, how much pressure will it exert on its container when it freezes?
164 views

Control the pressure of Hydrogen in a small container without the use of a pressure regulator

I had recently asked this question, and due to the comments and general consensus of safety concerns, I decided to re-ask the question, attacking the problem from another angle. The Problem I need to ...
507 views

How to treat pressure in computational chemistry?

I have a reaction where a gas at high pressure and a solution with all kinds of species is involved. How do I take pressure correctly into account to get reasonable values for $G$? Do I calculate ...
852 views

Doubts on Diffusion/ Effusion of gases at different pressures

Let's start with a question: "One mole of nitrogen gas at 0.8 atm takes 38 s to diffuse through a pinhole, whereas one mole of an unknown compound of Xenon with fluorine at 1.6 atm takes 57 s to ...
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Is the pressure of a gas proportional with the concentration of a gas?

Is the pressure of a gas proportional with the concentration of a gas? Because you can also use the pressure instead of the concentration in the equilibrium condition.
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Thermodynamics : Work Done by a Gas

Suppose in a piston in which there is a gas, the gas exerts pressure P on surroundings, whereas the surrounding exerts a pressure $P[ext]$ on the gas. In order for the gas to expand, P must be ...
1k views

How accurate would be the following conclusion on 'Critical Temperature'?

"Boiling does not occur when liquid is heated in a closed vessel. On heating continuously vapour pressure increases. At first a boundary is visible between the liquid and vapour phases because liquid ...
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Vapor Pressure - Sealed Vessel

I have read that vapor pressure is only affected by temperature, but all of the examples have been in a sealed vessel. I have also read that pressure does not affect vapor pressure. I am looking for ...
190 views

Pressure increase on rate of reaction

For reactions involving gases, an increase in pressure is no different from increasing the concentration of reactant particles, thus increasing the rate of reaction. But for reactions involves ...
10k views

How to figure out which substance has the highest osmotic pressure? [closed]

In preparing for an exam and I'm trying to solve the following question. I'm clueless. What should I do? Which of the following water solutions has the highest osmotic pressure? \begin{align} \...
882 views

Partial Pressure and Partial Molar Volume

When we define partial pressure and partial molar volume of a gas in a mixture, suppose $P$ is partial pressure of a gas in a mixture and $V$ is partial molar volume then why the following equation ...
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How does iceskating work?

I was willing to understand a little bit better the physics behind iceskating. Messy thoughts From New Scientist (1964) (probably not the most up-to-date reference $\ddot \smile$), I found a diagram ...
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When water boils at its boiling point how do we call it as an equilibrium?

On boiling, water becomes a vapor, liquid volume decreases and vapour volume increases. Since volumes are not constant, how do we call it as equilibrium?
328 views

Non-Ideal Gas Behavior

I obtained measurements of temperature and pressure at various temperatures ($-10, 0, 20, \text{ and } 50^\circ \mathrm{C}$) and plotted them on a graph. Projecting backwards, the best-fit line ...
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What is the temperature at which lava evaporates?

According to this article -> http://ntrs.nasa.gov/search.jsp?R=19660041998 Lava evaporates under natural conditions, but apparently, only a little bit. I'd like to know the temperature at which ...
825 views

Stability of CN molecule

The $\ce{CN}$ molecule has been observed spectroscopically in comets where pressure has been estimated to be as low as $10^{-10}\ \mathrm{mmHg}$. Draw a Lewis structure for $\ce{CN}$. Suggest an ...
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Does the van der Waals equation remain valid when repulsive intermolecular forces dominate?

The van der Waals equation for a real gas is: $$RT =\left(p+\frac{a}{V_\mathrm{m}^2}\right)(V_\mathrm{m}-b)$$ We have understood this formula by saying that $a$ is the term which is for force of ...
850 views

Can gaseous hydrogen and gaseous oxygen be compressed without reaction?

I'm looking into building a clean Bunsen-style burner (or rocket engine - I haven't decided yet). I will be using electrolysis to extract hydrogen and oxygen from water, but the apparatus I am ...
122 views

How to test acid-base reactions under pressure?

I am trying to test chemical reactions, more specifically reactions between an acid and a base, at different levels of pressure. I would like to know if there is some kind of equipment I can get that ...
448 views

What is the pressure belonging to in Boyle's Law?

Just a hour ago, I was reading the great and highly interesting, Boyle's Law. In my textbook, there is given Boyle's Law and leaving some pages, there is stated Dalton's Law of Partial Pressure. ...
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How to calculate air tank capacity from tank displacement, tank fill (gauge) pressure, and specific type of gas?

I am trying to calculate the amount of a specific compressed gas that will fit in an air tank of specific displacement, at a specific pressure. This is in reference to compressed air guns. The inputs ...
160 views

When fugacity and z-compressability equations instead of Gibbs free energy equations?

In very high pressure environments such as mud circulating systems, conditions for polymers contain fugacity/z-compressability criteria instead of Gibbs free energy, more in the answer. So When ...
17k views

What is the relation between partial pressure and concentration?

So, one of my books said that partial pressure plays more significance in determining the gradient than concentration. So, it said it was possible for a gas to go from high partial pressure at point A ...
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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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Convert from Pa to Pa to J/dm^3 [closed]

Given the value 380 PaK^-1, how do I convert Pa to Jdm-3? I know that 1 joule = 1 Nm, and that 1 pascal = 1 N/m^2. But where does the dm^-3 (or L) come into this? I don't know where to start.