Questions tagged [gas-phase-chemistry]
For questions relating to the chemistry of rections which occur when the reagents are both in the gaseous state
89 questions
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Demon Kinematics: Estimating Moles converted/kWh in a (gas phase) Flow System
I have a magic demon that watches passing air and changes some of the molecules of type A to B. (It's actually a reaction, obviously, but what it specifically is probably doesn't matter for present ...
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Standard enthalpies of reactions involving multiple gases as reactants
I'm confused by the definition of standard enthalpy of reaction. Consider a reaction which has multiple gases as reactants, such as the one below which shows the combustion of methane.
$$\ce{CH4 (g) + ...
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Evaluating the density of a gas equilibrium mixture
I'm a beginner in chemistry (first year uni course) and I have this exercise that I need some help with. I don't really know where to start so for now. I've tried random approaches to see what works ...
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Liquification of ideal solution of two liquids from vapor phase [closed]
A and B form an ideal solution. In a cylinder piston arrangement, $\pu{2.0 mol}$ of vapor of liquid A and $\pu{3 mol}$ of vapor of liquid B are taken at $\pu{300 torr}$ and $T~\pu{K}$. At what ...
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Calculating Rotational Temperature from an FTIR Spectrum
I am trying to calculate the rotational temperature of a sample of gas phase HCN from an FTIR spectrum. It's a 10 Torr sample in a 10 cm gas cell, held at room temperature. In theory, I should be able ...
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Water dissociation constant $K_w$ in vapour, or are there charges entities ($\ce{H3O+}$, $\ce{HO-}$,...) in water vapour?
When water is in vapour state, to which degree is there still some dissociation with the existence of charged species like $\ce{H3O+}$ and $\ce{HO-}$? (I would be interested by any reference to ...
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Estimate scaled up rate of gas phase reaction
I have measured the conversion rate of a particulate-catalyzed gas phase reaction in a reactor. That is, I have a graph of how fast $\pu{1 mol}$ of catalyst converts $\pu{1 mol}$ of reactant into $\pu{...
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Can we calculate van der Waals' constant a for the following case?
The given Z vs P curve for 1 mole of a gas at 400K starts at Z=1 & P=0.
The slope at the point when the curve again intersect Z=1 is 0.005. The critical temperature of the gas is 500K.
My approach:...
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Why is the van der Waals constant b of NH3 less than that of N2?
According to the actual data, van der Waals constant $b$ of $\ce{NH3}$ gas is $\pu{0.0371 L mol-1}$ and that of of $\ce{N2}$ gas is $\pu{0.0387 L mol-1}$.
But it should be,
$$b_{\ce{NH3}}>b_{\ce{...
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what's the difference between gas and vapour? [duplicate]
In the lecture, our teacher said that the significant difference between gas and vapour is we can't liquefy gas just by compressing it but it's not the same in the case of vapour."
So, I'm ...
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What is the Volume occupied by gas at extreme or limiting conditions of volume? [closed]
We know that
1 Mole of an Ideal Gas occupies 22.4 L at STP.
[real gases also are also close to this volume , even tho there might be deviation, for this experiment let's take both to be same]
But it'...
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Is there a chemical compound which does not have a liquid state but a solid and a gaseous state? [duplicate]
Is there a chemical compound which does not have a liquid state but a solid and a gaseous state? Meaning no matter the temperature or pressure it will never be in its liquid form. According to my ...
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A new green method for purifying acetylene with the help of Zeolite molecular sieve
I'm investigating for a green method for purification of acetylene in order to reduce the environmental impacts in manufacturing plants. In the current method mercuric chloride is used in the ...
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How would you remove sulfur hexafluoride from a gas sample?
What procedures would be available to remove SF6 from a sample (or stream) of gas?
The ideal answer would be a list of options. If it helps, please assume the rest of the sample consists of noble ...
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Pressure and temperature relation of Novec 1230
I am working on a concept turbine for a school project which operates at low temperature so it's necessary for me to have a pressure temperature relation of this chemical or novec 7100 also is okay.. ...
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How do I calculate the temperature change in a gaseous reaction?
So, with $\pu{3 mol}$ of $\ce{H2}$ and $\pu{3 mol}$ of $\ce{Cl2}$ and given the reaction $\ce{H2(g) + Cl2(g) -> 2 HCl(g)}$ with $\Delta H=\pu{-184.6 kJ/mol}$, I am supposed to calculate the work ...
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Explaining the process of boiling a liquid
I am confused by the thermodynamic definition of boiling. It is stated that boiling occurs when the vapor pressure of a liquid is the same as the ambient atmosphere. Now suppose we deal with an open ...
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Vapor-Liquid Equilibrium and partial pressure of ammonia
I tried searching the forums for a similar question but I do not think it was entirely answered:
Suppose I have a closed system in a container with solvent and a certain concentration of gas, say ...
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If Graham's law doesn't apply to the ammonia and hydrogen chloride diffusion in a glass tube demonstration, is there a law that does?
A comment below What exactly are "white fumes" and why does holding a bottle of ammonia (conc) next to a bottle of HCl (conc) make them? links to The
Royal Society Of Chemistry video ...
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Why can't there be a gas-dispersed-in-gas colloid? [closed]
Colloids, a special type of heterogeneous mixtures, typically have two components. One is the dispersed phase (DP), which is the "solute-like" part and another one is the dispersion medium (...
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Could an LPG gas ever become lighter than air?
Both of the LPG gases, propane ($\ce{C3H8}$) and butane ($\ce{C4H10}$) are heavier than air. Propane is $1.55$ times heavier and butane is $2.08$ times heavier. Is same-temperature air always lighter ...
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How to adjust selectivity of gas-permeable PDMS membranes for environmental applications?
I have an idea about making an environmental sensor that uses a gas-permeable membrane (GMP) and how its probe could be submerged in a water source with an off the shelf gas sensor.
So far, my ...
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Why does steam store large amounts of energy?
We all know that steam can be used to perform mechanical work and steam has a high capacity for energy storage. But why does steam have such high energy capacity?
I tried searching for answers on the ...
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Regulator oxidizing NO to NO2
I have a regulator that is somehow oxidizing NO to NO2. Using a different regulator does not cause this same issue. I was wondering what could possible be contaminating the regulator that would ...
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Hydrogen concentration measurement without gas chromatography
Please suggest ways to measure $\ce{H2}$ concentration in a sample of gas containing $\ce{HCl},$ $\ce{CH4},$ $\ce{N2},$ $\ce{CO2}$ and trace amounts of chlorosilanes without GC.
The problem is that I ...
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Can there be a gas-phase electrolyte?
Reading the first paragraph in Wikipedia's I found one sentence particularly interesting:
Some gases, such as hydrogen chloride ($\ce{HCl}$), under conditions of high temperature or low pressure can ...
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A physical meaning of the Danckwerts boundary condition in terms of concentration profile (adsorption)
Can someone please explain to me in a simplified way, what exactly does a well-recognized Danckwerts boundary condition do to the concentration profile of adsorption phenomena? I just cannot find a ...
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Which temperature would allow a molecule to vaporize at ultra-low pressure? [closed]
I must vaporize a molecule with a normal boiling point of 320°C. Now I work with ultra-high vacuum and I need to bring my molecule to the gas phase. Has anyone a rough idea how high the temperature ...
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Retention Time of Isotopologues
In several sources I have read that heavier isotopologues eluate earlier than lighter ones.
As explanation vapor isotope effects are given.
But this is something I do not understand. I tought in a GC ...
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Molecular diffusivity of a three-component mixture
I usually used a following expression by Fuller & Schettler & Giddings to predict molecular diffusivities of binary mixtures:
\begin{equation}
D_i = \dfrac{1\cdot 10^{-4}\left(0.00143\cdot T^{...
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How to generate sulphuric acid vapour to test an analyzer?
We have a UV gas analyzer we want to test to see if it reads gas phase $\ce{H2SO4}$. How can we safely produce less than $\pu{5 ppm}~\ce{H2SO4}$ as a spike test to see if the analyzer sees the spectra?...
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Why does Sulfur dioxide incompletely freeze when entrained in a helium stream inside tubing dipped in liquid nitrogen?
Background - In a laboratory setting, I use typical elemental analysis (EA) to generate about 50 µg of sulfur in the form of sulfur dioxide (SO2). The EA uses a helium carrier. As an example, a sample ...
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What non-hazardous substance can be used to locally turn sky red?
I am a horror author and I have a scene coming up in my new book where I need a red-colored gas (or a gas that would somehow be turned or viewed red when viewed from the ground) to be spilled into the ...
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What chemical could be used as carbon monoxide scrubber?
I am trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of $\ce{CO},$ $\ce{H2O}$ and $\ce{N2}.$ Only $\ce{CO}$ is unwanted in this case.
Could I use calcium ...
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Purging submersible with nitrogen
I do a lot of short term ocean field deployments where system electronics are self contained in a submersible enclosure. A new project I'm working on requires a long term deployment in the deep ocean. ...
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CP2K Spherical Cell
I'm trying to run a gas phase cluster calculation in CP2K. I want to create an outside force to constrain water molecules that are in the simulation within a radius of a central ion. I want to create ...
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Is there an actual specific heat for aluminum in its gaseous state? [closed]
I've scourged the internet and I can't seem to find it anywhere although I've found the specific heat values for aluminum in both solid and liquid states. I'm trying to construct a heating curve and I ...
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Can you make n-Hexane a supercritical fluid? [closed]
When making aerogel using supercritical fluids the liquid in the gel is replaced by a gas. Can this be achieved using n-Hexane as the supercritical fluid? What would the resulting gas be? Would it be ...
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Are all gases equal in their ability to carry with them lower volatility matter at a given temperature? [closed]
As we all know water is a great solvent in it's liquid form relative to other substances. I wonder however how it performs as a gas relative to other stuff.
Does anyone know how well steam carries ...
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Does davis safety lamp detect explosive gases in ship compartments? [closed]
I feel managers at Bangladesh ship breaking yard are not properly caring for safety of workers. Many workers die in explosions while salvaging metal. documentary available on YouTube by National ...
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How can CO2 exist in two different phases?
Given a container of $\ce{CO2}$ at a pressure of 100 bar and 295 K, I check the chart below and find:
I'm within the liquid region
I'm before the critical point (304 K)
My question then is, why can ...
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why does the partial pressure not change? [closed]
Suppose I have the equilibrium in a closed container at constant temperature:
$$\ce{2CaSO4(s) -> 2CaO(s) + 2SO2(g) + O2(g)}$$
If the volume of the container is halved, the reaction should move ...
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Crossing at critical temperature of a gas
This is written in the book 'Treatise on Thermodynamics' by Max Plank-
the crossing of the critical temperature at any pressure other than the critical pressure differs in no way from the crossing of ...
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Vibrational state dependency of the reaction cross section
I'm reading p.1238 of Mcquarrie's Physical Chemistry: A Molecular Approach textbook.
In the last line of the page, the author explains that the value of the reaction cross section in the constant ...
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What limits supersaturation in the absence of nucleation sites? [closed]
Imagine a scenario where we have a chamber with air that is supersaturated with water vapour. In this ideal scenario there are no nucleation sites (e.g no suspended particles or nucleation on the ...
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What is fugacity?
When one attachs a manometer to car tires or carbon dioxide fire extinguishers, what is being measured: the pressure or the fugacity?
For ideal gases both are the same, but not for real gases.
As ...
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Does the property of additivity for the amounts of different substances hold up for ideal gas law?
A mixture contains $\pu{8.00 g}$ each of $\ce{O2},$ $\ce{CO2},$ and $\ce{SO2}$ at STP. Calculate the volume of this mixture. Which of the gases would exert the greatest pressure and why?
Here is my ...
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Equilibrium involving both gas phase and aqueous phase
If I have been given an equation that involves a gas-aqueous phase equilibria, how do I write the equilibrium constant?
I have come across several questions that give equations having BOTH gas and ...
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If the gaseous molecules didn't have any kinetic energy would the surface of a filled balloon still be firm? [closed]
The most of the ideal gas law equation is based on the fact that the gaseous molecules are moving around and cause collisions and thus have some pressure. If these molecules were to not have any ...
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Molecule or molecular ion that spontaneously breaks up in two different ways
I teach physics, and I'm looking for simple, easy examples from chemistry to use in order to illustrate basic ideas about quantum mechanics for my students. A conceptually simple example is the $\text{...
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