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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Pressure dependent rate coefficient
I am trying to study how the pressure will affect the formation of ozone at around 5 bar. So, I am looking for a simple relation between the reaction rate coefficient and the pressure to use it in my ...
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Is vapour pressure a surface phenomenon?
As a fact, I know that vapour pressure doesn't depend on surface area.
Does this imply it is not a surface phenomenon also?
It shouldn't be as then it would depend on surface area of molecules and ...
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Find the Total Pressure When the Faucet is Released
Two chambers are connected as shown in the figure. The total pressure of the first chamber that contains Ar and He gas is 98.4 atm. If the faucet is released, find the total pressure. (There's 1 mol ...
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Can a reactor be operated at both reflux and above atmospheric pressure?
I'm not a chemist by trade so my experience in the lab has probably not been as in-depth as most of you. I've been tasked with investigating a proposed reaction in which an organic mixture (mostly ...
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A formula for the refractive index of a gas dependent on temperature and pressure
I am in search for a formula that gives me the refractive index of a gas at a given temperature and pressure. Does such a formula exist? Ideally the solution should have this form:
$n_g(t, p) = \...
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Pressure-dependence of electrolysis voltage
I'm trying to better understand electro-chemistry, so please explain why this second-kind perpetual motion device won't work. I guess it's safe to assume it won't work one way or another.
There is a ...
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Finding Pressure of M in a Charge Exchange
Ar (RE = 15.5 eV) is the reagent gas in a charge exchange experiment. If Ar+ reacts with anisole with a rate constant of 2.26x10-10cm3 molecules-1/s-1 and 65% of the Ar ions react in 25 milliseconds, ...
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Calculating Equilibrium Partial Pressures Given Kp and Mass
For the reaction
$$\ce{AsCl5(g) <=> AsCl3(g) + Cl2(g)}$$
at $550$ K, the equilibrium constant ($K_p$) is $9.81$. Suppose that $3.150 \ g$ $\ce{AsCl5}$ is placed in an evacuated $600$ ml ...
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Why does increase in pressure cause a increase in boiling point [closed]
When we increase the atomospheric pressure pressure above the solution , the boiling point of a solution increases. Why does this happen?
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Volume of dried gas at STP
A $54.0\ \mathrm{mL}$ sample of oxygen is collected over water at $20\ \mathrm{^\circ C}$ and $770\ \mathrm{Torr}$ pressure. What is the volume of the dry gas at STP?
By using the combined gas law, I ...
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What will be unit of volume in V=nRT/p if p is in Torr instead of atm? [closed]
$V=nRT/p$, where $n$ is amount of gas in $\mathrm{mol}$, $R$ is gas constant, $V$ is volume in $\pu{dm3}$, and $p$ is pressure in $\pu{atm}$.
What happens to $R$ if $p$ is in $\pu{Torr}$ instead of $...
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Why is my solution for the partial pressures of two different gases incorrect?
I have the chemical equation: $\ce{NH4NO3(s) -> 2H2O (g) + N2O (g)}$. There are $12.8$ g of ammonium nitrate, and it decomposes completely in an empty container at $25.00\ ^\circ\pu{C}$ until the ...
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Defining the partial pressure equilibrium concentration
First off, I am not a chemist. I'm an engineer with an interest in thermodynamics for engine simulation for the basis of emissions. So if I have asked something stupid, this will be why.
So I am ...
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what is actually supercritical fluid? [duplicate]
let’s take an example: if we have a glove-box filled with helium at 5 bars at room temperature which is far beyond its critical point, what actually it would be like ?
would it be like a normal gas ? ...
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Changes in pressure for an equilibrium reaction containing a solid/liquid on one side only
For a reaction where there is only one solid/liquid present, but gases present as both reactants and products (are there any examples of this type of reaction?):
$$\ce{A(s) + B(g) <=> C(g)},$$
...
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What is a simple formula to approximate the change in relative humidity as temperature rises/falls?
The moisture-carrying ability of air goes up as the temperature rises. So if I take a volume of air and heat it or cool it (allowing it to expand/contract so the pressure remains constant) how can I ...
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Equalization of pressure in heat exchanger
I was solving numericals on Kinetic Theory of Gases when I came across this question
Two closed vessel of equal volume contain air at 105 kPa, 300 K and are connected through narrow tube. If one of ...
user66707
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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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Does the rate constant depend on pressure?
I have read in some books that when pressure increases, the number of effective collisions increases. Hence, $k$ depends on pressure. Is it true? If so, then why doesn't $k$ depends on concentration? ...
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Molar mass of a protein from osmotic pressure
The height of a column of liquid that can be supported by a given pressure is inversely proportional to its density. An aqueous solution
of $0.010 g$ of a protein in $10 mL$ of water at $20^oC$ ...
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How to evacuate a glass vessel containing powders?
I would like to evacuate a vessel (a glass round-bottomed flask) and which contains a few grams of platinum. However, I am worried about the platinum powder being sucked up by the vacuum.
A few ...
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Why does the liquid in an Oralmedic stick flow uphill after I turn it upside-down?
I was experimenting with an Oralmedic stick, which is basically a cotton swab with a hollow stick that has liquid medicine inside, and observed something very unexpected. I followed the usage ...
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Is it true that an evaporating molecule has the same kinetic energy as a molecule in a pot of boiling water?
A molecule on the surface of room-temperature water shoots off the surface of said water, or in other words, it "evaporates." It does so because it gained kinetic energy ${x}$, and ${x}$ was great ...
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Up to which temperature and pressure can dendrimers (PAMAM) be stable?
I am preparing PAMAM (poly amido-amine) dendrimer and I want to know up to which temperature and pressure can it be stable?
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Find the boiling point of a compound given a pressure
I need to find the boiling point (in degrees centigrade) of ethanol on a day when the atmospheric pressure is $780\text{ torr}$.
I know that the molar mass of ethanol is $46.07\text{ g/mol}$ but I ...
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How to synthesize a material at 2000atmospheres?
I am trying to combine various elments and at high pressure. How to achieve these pressures for a gas and in quantities of at least 1 cubic centimeter.
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Gas concentrations along the gradient from sea level to deep-sea
Studying scuba diving-related phenomenas I thought about how to estimate gases concentration down the sea.
Of course, solubility of gases at, for example, $5$ atm of pressure, can be estimated with ...
user43021
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What does the osmotic pressure do in an electrolytic solution?
I have learnt that in an electrochemical cell, the osmotic pressure in the solution hinders the flow of ions from the electrode to the solution, rather some ions may accumulate on the electrode ...
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Molecular kinetic interpretation of pressure
Regarding the molecular kinetic interpretation of pressure, we arrive at a point in the $F=\frac{\Delta P}{\Delta t}=\frac{2mvx}{\Delta t}$, that is to say, the force exerted in the shock on the wall ...
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Can air inside a high temperature (1300C) Kiln cause an explosion?
I saw many kiln designs that lack an opening for hot\pressurized air to come out , or any pressure valve.
But when air is heated to such a high temperature (1300C) inside a closed chamber (the kiln), ...
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Conversion of a permeability value from barrer to SI unit
I have done a permeability experiment on LDPE in the presence of air. At $\pu{30^\circ C}$, the permeability was found to be 1.846 barrer.
Now I am trying to apply this permeability value to a ...
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Does the way a reaction with gas moles shifts depend on Q or number of moles on either side of the reaction?
Given a container with the reaction $\ce{C2H4{(g)} + HCl{(g)} -> C2H5Cl{(g)}}$, if we inject $\ce{C2H5Cl{(g)}}$ to the container, what will happen?
I thought of this in two different ways and got ...
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Will ice be cold or not when formed using pressure? [closed]
We know that ice can be formed either by lowering the temperature of water or by applying more pressure. If we lower the temperature of water the ice so formed will be cool which is obvious.
If ice ...
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How do the pressure acting on the reactants and the initial temperature of the reactants affect the enthalpy of reaction?
In an exothermic reaction that occurs under constant pressure, does the pressure acting on the reactants affect the enthalpy of reaction? Does the initial temperature of the reactants affect the ...
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Can heat capacity at constant volume for a gas decrease as temperature increases? [closed]
I found a function for the $C_V$ of a gas which is being heated under constant volume,but the function shows that the $C_V$ is decreasing. I was wondering if this is possible for any gas since I know ...
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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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Can the pyrophoric tendencies of a pyrophoric substance be suppressed in a pressurized environment?
It's common knowledge that the pressure of an environment influences many properties of a substance, like the melting point, boiling point, or triple point. Pyrophoric substances ignite spontaneously ...
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Le Chatelier’s principle when pressure of gases increased with the same stoichiometric coefficient
$$\ce{C (s) + H2O (g) <=> CO2 (g) + H2 (g)}$$
What will happen to the equilibrium when the pressure of gases is increased? What will happen to the yield of $\ce{H2}$?
Since pressure increased ...
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Pressure dependency in Haber Bosch ammonia synthesis
Haber-Bosch ammonia synthesis reaction:
$$\ce{3H2 +N2 -> 2NH3}$$
According to the ideal gas law: $pV=nRT$ where constant volume implies $\displaystyle \frac nV=\frac p{RT}$
Then $\displaystyle ...
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Why do gases liquify under pressure?
To my understanding, an increase in pressure (of gases in a container) is proportional to an increase in gases' kinetic energy, and hence temperature. However I read that gases liquify under pressure.....
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Pressure-Volume Formula Question
I have a chemistry homework problem that states the following:
$6.2$ L of $N_2$ at $0.74$ bar is mixed with a $15.2$ L sample of $O_2$ at $0.35$ bar. The gaseous mixture is placed in a container of ...
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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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Can every liquid pure substance be compressed to solid?
Apart form the fact that liquid are often misleadingly considered incompressible,
fact that I recently find out to be true only as an approximation in specific circumstances.
I was curious to know if ...
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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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Calculating Gas Pressure with Water Vapour
$\pu{4.0 L}$ of oxygen was collected by the displacement of water at $\pu{105.0 kPa}$ pressure and $\pu{30 ^\circ C}$. If the vapour pressure of water at $\pu{30 ^\circ C}$ is $\pu{4.2 kPa}$, ...
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How can pressure build up in an equimolar gaseous reaction? [closed]
To make the question concrete, if you conduct a reaction like $\ce{H2 + Cl2 -> 2HCl}$ in a stoppered test tube, the stopper will aggressively pop off (or the glass will shatter) despite the fact ...
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Physical Explanation for variation of Gibbs Free Energy with Temperature and Pressure
Reading Atkins Elements of Physical Chemistry right now, and the book says:
"At constant pressure and entropy, an increase in temperature ($\Delta T\gt0$) results in a decrease in $G_\mathrm m$ (molar ...
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Weight percentage of a component in gaseous mixture
Given a mixture of $\ce{He}$ and $\ce{O2}$ with density $\pu{0.47 g/L}$, temperature $\pu{298.15 K}$ and pressure $\pu{0.948 atm}$. What is the weight % of $\ce{He}$?
I get stuck in the formula
$$\...
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Calculate ozone layer thickness at a given temperature and pressure [closed]
The ozone concentration in the upper atmosphere averages $\pu{3.0 \times 10^13 molecules per cm3}$ in a region between $15$ and $\pu{35 km}$ high, at an average pressure of $\pu{0.001 atm}$ and ...
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Is brass combustible in high pressure oxygen environment?
Some metals are particularly ignitable in high pressure oxygen environments, like stainless steel and aluminum. Copper and nickel, on the other hand will self-extinguish when ignited. Does anyone know ...
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