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28 votes
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Gaseous metals?

No, gaseous metals do not retain metallic bonds, nor metallic conductivity, nor luster, nor any other metallic properties. They are no different from other gases. True, they typically require pretty ...
Ivan Neretin's user avatar
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11 votes
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What is fugacity?

The original paper of Lewis [1, p. 54], who invented the concept of fugacity explains it in a clearer way than Wikipedia's convoluted explanation: II. FUGACITY. If any phase containing a ...
ACR's user avatar
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8 votes
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How are London Dispersion Forces generated?

Let me crash the party here. TL;DR: The classical explanation of induced dipole attractions from electron densities "evading" each other does, by itself, not adequately or intuitively ...
Antimon's user avatar
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8 votes
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How can CO2 exist in two different phases?

The $\ce{CO2}$ exists in two phases when you buy a partially-filled $\ce{CO2}$ cylinder because there is extra volume (which is needed to allow expansion as the container warms). Therefore, the ...
DrMoishe Pippik's user avatar
7 votes
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Is there a metal for which its gas is necessarily a plasma?

In principle, all that is required is for a substance to evaporate from a liquid into a plasma directly is for its ionisation energy to be significantly smaller than the average kinetic energy of its ...
Nicolau Saker Neto's user avatar
7 votes

Gaseous metals?

I'm not an expert, but I think some metals boil directly into the plasma state, and that other metals (and most other gasses in general) start out as almost entirely unionized gasses when they boil ...
Mr. Nichan's user avatar
6 votes
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Detecting trash (plastic) burning smoke with sensors

The typical gas sensor marketed to hobbyists and enthusiasts (except for $\ce{CO2}$) are of the metal oxide semiconductor type, not to be confused with MOS as in MOSFET. How do these work? In these ...
uhoh's user avatar
  • 5,900
6 votes

Molecule or molecular ion that spontaneously breaks up in two different ways

This happens all of the time in mass spectrometry following electron-impact ionization. Following ionization, each molecular ion decomposes (or fragments, to use mass spectrometry lingo) into other ...
Ben Norris's user avatar
6 votes
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Why is the van der Waals constant b of NH3 less than that of N2?

From a purely geometrical standpoint and using some simple assumptions the similarity and order of b parameters should not be all that surprising. For ammonia the longest distance in the molecule can ...
Buck Thorn's user avatar
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5 votes

How are London Dispersion Forces generated?

You are correct that simply stating that the Schrodinger equation is time dependent does not really answer the question. In fact, time-dependence is not a component of the derivation of the ...
PJ R's user avatar
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5 votes
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Why is volume inversely proportional to pressure?

Given you know and understand Charles' and Gay-Lussac's laws, it's not about chemistry, rather, simple ratios: $$ \begin{cases} T \propto V\\ T \propto p \end{cases} \implies p \propto \frac 1 V $$ ...
andselisk's user avatar
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5 votes
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Is there an element with no liquid state?

The answer to your question is no, there is no element with no liquid state. The state of an element (or molecule) depends on the temperature and the pressure. All elements can be in any of the three ...
KarlsMaranjs's user avatar
4 votes
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Gas solution - State of matter

Good question! For a solid dissolved in liquid, obviously the solid behaves as a liquid rather than as a solid, since its particles are separated and moving freely. A gas, though, is defined as free ...
DrMoishe Pippik's user avatar
4 votes

What does the reaction of hydrogen and iodine to hydrogen iodide look like?

To show an example for equilibrium reactions to your students, you can use a reaction which has visual change as shifting the equilibrium position such as color. My best bet is, use of cobalt(II) ...
Mathew Mahindaratne's user avatar
4 votes

How does Le Chatelier's principle apply to a gas phase reaction at constant volume?

Let's see your formula (with the difference of enthalpy being negative): $$\ce{2CO (g) + O2 (g) <=> 2CO2 (g)}\qquad(\Delta H^\circ<0)$$ At constant temperature, for Le Chatêlier purposes, ...
Geraldine's user avatar
4 votes
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Is there a phase diagram available for hydrogen fluoride?

Linde Gas contains a vapor pressure curve. Note that this does not extend to Venusian surface temperatures which are above the critical point. Hydrogen fluoride may not lift as well as you think. ...
Oscar Lanzi's user avatar
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4 votes
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Do companies recover carbon dioxide and water from the purification step of cryogenic air separation, and how?

It is unlikely that this is an economically feasible $\ce{CO2}$ recovery method, which means commercial gas producers probably don't bother to isolate $\ce{CO2}$ this way (surely not water). The ...
Buck Thorn's user avatar
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4 votes
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Can you make n-Hexane a supercritical fluid?

A supercritical fluid is just a state of matter. like solid, liquid or gas. Hexane is no more or less toxic if it has become supercritical and then brought back to standard temperature and pressure, ...
DrMoishe Pippik's user avatar
4 votes

Can there be a gas-phase electrolyte?

I think, it is a result of the word having multiple definitions in different contexts. Specifically, the original definition in context of chemistry Electrolyte is a solid, causing electrical ...
permeakra's user avatar
  • 21.7k
4 votes

Pressure and temperature relation of Novec 1230

Novec™ 1230 is basically just 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)pentan-3-one. The pressure–temperature relation is given by the manufacturer as a graph: Novec™ 7100 is a mixture of 1,1,...
Loong's user avatar
  • 4,826
3 votes

How can I find the Van der Waals constants (a and b) without any critical values?

I would approach this a little differently. I would integrate the pressure between $V_D$ and $V_B$, such that the average pressure is 17.76 bars: $$\frac{\int_{V_D}^{V_B}{PdV}}{(V_B-V_D)}=17.76$$or, ...
Chet Miller's user avatar
  • 13.5k
3 votes

Rate law equation - orders?

You are correct, the reaction order cannot be deduced from the brutto-equation and is usually determined experimentally. However, here you are presented with the elementary reactions and their rates. ...
andselisk's user avatar
  • 38.4k
3 votes

A confusion regarding gases

The correct resolution of your question is that gravity does affect gas molecules but not so much that it matters to a measurable extent when doing laboratory-scale experiments that don't involve ...
matt_black's user avatar
3 votes
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Is the %V/V composition defined for homogeneous mixtures?

Let's be clear on what percent by volume means. If I say component $X$ is 25% by volume of a mixture of $X$ and $Y$, with a total volume of 1 L, it does not mean there is some 250 mL portion of the ...
Christopher Grayce's user avatar
3 votes
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Description of a van't Hoff apparatus

The Van't Hoff equilibrium box is a chamber containing a mixture of reactants and products at equilibrium. It is connected to an array of cylinders, each containing one of the pure reactants or ...
Chet Miller's user avatar
  • 13.5k
3 votes

Molecule or molecular ion that spontaneously breaks up in two different ways

There are many compounds that will break down into different products when involved in collisions with inert molecules. For example, $\ce{F3-}$ can separate into $\ce{F2 + F-}$ or into $\ce{F. + F2-}$....
Andrew's user avatar
  • 10.3k
3 votes

Molecule or molecular ion that spontaneously breaks up in two different ways

The key operation is to make a metastable particle that has at least two decomposition pathways and a short lifetime. Fragmentation is probably the key word you were looking for. Pyrolytic ...
James Gaidis's user avatar
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3 votes
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Equilibrium involving both gas phase and aqueous phase

I dare say most equilibrium constant don't cite specific units because the appropriate units are implied implicitly. In the case of the reaction: $$\ce{R-NH2(g) <=>[aqueous] R-NH3+ + OH-}$$ I'...
MaxW's user avatar
  • 22.3k
3 votes

Vibrational state dependency of the reaction cross section

Vibrations are very important for reactions. In the particular example of $\ce{H2+(g) + He}$ vibrational levels 0-3 have an energy less than E0 (minimum energy for reaction), so additional ...
Cody Aldaz's user avatar
3 votes

Hydrogen concentration measurement without gas chromatography

There are commercial, calibrated, hydrogen detectors, such as those from GasSensing or from Mcmaster-Carr, but you'd have to check with the supplier or manufacturer to determine if the other gases ...
DrMoishe Pippik's user avatar

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