Study of macroscopic and microscopic phenomena in chemical systems in terms of physical laws and concepts [thermodynamics, statistical mechanics, kinetic theory, quantum mechanics...].

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277 views

What's up in this SPAWAR video?

Here is a video presentation of infrared recordings of anomalous heating in a deuterium palladium cell: ( youtube video) (see also this presentation if you want more detail, and have time). There are ...
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3answers
368 views

Can endergonic reactions occur outside of living organisms?

If the Gibbs free energy equation is defined as: ∆G = ∆H - T∆S And the amount of energy/work released from a reaction is: ...
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1k views

How do I integrate the Poisson equation to determine the electric potential along a particular direction (e.g., $z$)?

This question is a sequel of sorts to my earlier (resolved) question about a recent paper. In the paper, the authors performed molecular dynamics (MD) simulations of parallel-plate supercapacitors, ...
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16k views

Do salt lamps really produce negative ions?

Do salt lamps really produce negative ions? Do you know about any scientific study that could support this assertion or disprove it?
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58 views

How do we represent 'smell' and 'taste' as signals?

I was wondering if we could represent 'smell' and 'taste' as signals like we do for audio. How do we mathematically represent them? Is there any research papers related to it? Can someone give me ...
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4answers
153 views

Solids: is energy expended in some fashion by, say, a table to keep the top from sinking down against gravity?

A friend and I were discussing this, and couldn't decide. Since it takes energy to physically raise something up above the planet's surface, does it continue to require energy in order to keep it ...
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1answer
701 views

Will the “Vacuum Wine Saver” suck the bubbles out of Champagne?

The "Vacuum Wine Saver" comes with the following "warning": Not for sparkling wines Intuitively and naively, I imagine that the bubbles (or the "bubble-potential"—my made-up terminology) will be ...
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2answers
85 views

Aggregating daily readings with units of parts per million

I have a series of daily readings (NOx emissions) measured in parts per million. I need to aggregate the daily readings into a monthly measure. Clearly a sum operation will be incorrect (parts per ...
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2answers
70 views

Atomic orbitals

I just studied atomic orbitals in a theoretical QM class, and I'm left with several questions, that are probably more questions in quantum chemistry: Many orbitals seem to have a preferred axis - ...
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1answer
89 views

Does O$^{2-}$ really exist?

In chemistry it is common sense that we have O$^{2-}$. But from a physical point of view, does O$^{2-}$ really exist as a negative ion? I mean, as an isolated ion. It is not apparent that a neutral ...
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625 views

Gas viscosity at high pressure, high temperature

EDIT 1 PER COMMENTS I am wanting to model nitrogen gas viscosity as a function of pressure and temperature OR learn of an existing equation that models nitrogen viscosity for the pressure and ...
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1answer
45 views

Hydrogen extraction efficiency of newish nano particle AA battery

The internet is ablaze with the new nano particle based extraction method of converting water to hydrogen. In 2002/2003 when I was 16 there was a similar craze about a lawn mower motor which ...
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1answer
95 views

Why does intramolecular hydrogen bonding cause molecules to separate?

Today I learned about intramolecular hydrogen bonding, which occurs in molecules such as ortho-nitro-phenol. What I was told is that, in case of intramolecular bonding, the molecules separate from ...
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1answer
149 views

Chemistry from a physical perspective [duplicate]

I'm currently learning chemistry for the first time, and loving it. I have a reasonably good physics and maths background and it's great to see things like spherical harmonics in quantum mechanics ...
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125 views

In which direction does the electron move during an electronic transition?

Let's imagine a molecule and put it in a 3D space. Let's also imagine an electronic transition for this molecule. I know how an electronic transition works, how to value if it is possible (using the ...
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2answers
695 views

Vaporizing ethanol from liquid

What is going on here http://youtu.be/LQFmKPA-iAg Is ethanol leaving the liquid? If so, why? Does the pressure add energy to the ethanol molecules causing them to gasify and move rapidly near border ...
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1answer
5k views

Can I calculate the maximum concentration of sucrose that will dissolve in water at STP using physical constants?

I am interested in identifying the maximum solubility of sucrose in water. Can this value be estimated based on the physical properties of sucrose? Eventually I will need this in degrees Brix (%w/w). ...
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1answer
48 views

Should it really be called “valence *sub*shell”?

The Wikipedia article on electron shells states this, which I (a chemical layman) also always assumed: The electrons in the outermost occupied shell (or shells) determine the chemical properties ...
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1answer
61 views

why some elements of same group cannot be used for doping semiconductors?

15th group elements like As, Sb, P can be used for doping whereas N and Bi cannot be used for doping even though they too belong belong to 15th group. Why ?
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199 views

Why does a bucket of Water weigh more than a bucket of Air?

Given the numerous chemical compounds found in dry air [compressed into a liquid] of a given volume [lets say $22.4$ L for simplicities sake] whose atomic weights far surpass that of water alone ...
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1answer
163 views

Smoothed Particle Hydrodynamics, Chemical Reactions and Stiffness [closed]

Dear people from stackexchange physics. I have been using SPH for quite a while to simulate free boundary flow, and just recently we tried to include some kind of (simple) chemical reaction in our ...
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2answers
389 views

First principle calculation of boiling point of water

How can we theoretically calculate the boiling point of water at given pressure (other subtle parameters as well, if any)? What is the most accurate (minimum discrepancy with experimental value) ...
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1answer
450 views

What is tricritical point?

Critical point is the transition temperature of a second order phase transition. But what does tricritical point mean? WIki says that a tricritical point is a point in the phase diagram of a system at ...
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2answers
88 views

Atomic layer deposition applications?

What unexplored areas (known unknowns) are there in atomic layer deposition (ALD)? What unexplored applications of ALD are there? It seems like people use it a lot for coatings of either insulators or ...
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1answer
136 views

what gives the vermiculite it's insultative properties

i know that vermiculite is used in insulation applications. i found this notion of the R-value of vermiculite, that i don't know if its true. basically i want to know if the attribute of the ...
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1answer
29 views

Whats the maximum number of electrons that can fit into the outer shell of boron?

Whats the maximum number of electrons that can fit into the outer shell of boron? Like silicon has 4 electrons in the outer shell but the maximum it can hold is 8 electrons so whats the maximum number ...
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1answer
82 views

Increase in Solubility of a Gas with an Increase in Temperature

On the UC Davis ChemWiki I read, "some gases have an increase in solubility with an increase in temperature." I understand why this is applicable to solids in liquids such as water, but why is it ...
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1answer
55 views

Boiling is not well described? [duplicate]

It is said that boiling occurs only when the vapour pressure becomes equal to the pressure surrounding the vapour (say atmospheric pressure). Why does it take place only satisfying these conditions ...
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70 views

How much entropy is produced in evaporating water due to irreversible evaporation towards equilibrium (humidity=100%)?

$dS=dH/T_{boil}$ for the increase in entropy by changing a phase at saturation ($T=373\text K$ for $p=1\text {atm}$ for water). However, water also obviously evaporates below boiling point when ...
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406 views

Melting and Boiling Points of Odd Materials

In Chemistry, I was taught that there are three main states of matter: solid, liquid, and gas, and that heat and pressure determine that state. For some substances, the line is blurry between them. ...
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1answer
178 views

Is water a gas at critical density, room temperature?

I am quoting Chaikin, Lubensky, Principles of Condensed Matter Physics, p. 4. Now suppose we have a closed container of water vapor at a density of 0.322 g/cc at room temperature. As the ...
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127 views

Should a polyatomic crystal behave similarly to the bulk of each/either of its constituent elements?

Generally, metals are usually fairly conductive, but their oxides aren't. I know conductivity is just one attribute, but in general, should you expect a, say, diatomic bulk crystal's properties to be ...
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1answer
77 views

Slicing a surface concentration from a volumetric number concentration

Assume I have a given volumetric concentration $c$ of $N=10000$ particles in a qubic box of volume V: $$c = \frac{N}{V}$$ The units of $c$ are $$[c] = \frac{[\#]}{[m^3]}$$ Now if I introduce an ...
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290 views

Where does Computer Science background students fit in Theoretical Physics [closed]

I am basically an Electronics student - background in computer science (that's where I want to work). I applied for an internship in USA in a research institute where the group is focused in ...
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1answer
177 views

Searching the point group of symmetry

I am engaged in the field of quantum-chemical calculations using programs written by myself. I have found out that I have a problem in finding the point group symmetry of the molecule. The first idea ...
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1answer
3k views

How much disolved oxygen is removed by boiling water?

Apologies if this is a chemistry question I've read that drinking water contains dissolved oxygen to the tune of $10\:\rm{ppm}$. I've also read that raising the temperature of water will remove some ...
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2answers
1k views

How thin a filter to filter particles out of salt water to make salt for human consumption?

I have gathered some salt in the Death Valley and for the fun of it I would like to clean it and make it edible. The process I plan to follow is simple: Dissolve the salt in water. Boil water for ...
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1answer
108 views

Why don't the actinides start at neptunium?

In their physical and chemical properties, actinium, thorium, protactinium, and uranium are respectively similar to lanthanum, hafnium, tantalum, and tungsten, and thus would seem to belong ...
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1answer
8k views

List of immiscible liquids

I'm looking for a list of immiscible (and miscible) liquids. I currently developing a game that will use the property of differents liquid, some of them will mix, other will not (positioning in the ...
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38 views

Square of velocity = 2 times temperature times specific heat capacity ; seems too tidy [closed]

So I did some algebra and came up with the following $v^2 = 2Tc$ where $ v = $ average velocity of the particles $ T = $ tempreture $ c = $ specific heat capacity but this seems too tidy
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23 views

Given the Pair Correlation Functions for a Multi-component Fluid, is There a Simple Way to Obtain the Helmholtz Free Energy?

I think it may not be possible. Given all the pair correlation functions (e.g. calculated from Ornstein Zernike theory), it seems possible to obtain the internal energy (assuming different species ...
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172 views

Confusing Chemical potential of mixtures

I feel that there are very few textbook that treat the chemical potential of mixtures in an understandable clear way, which is why I wanted to ask here about certain things? Although I do not have a ...
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0answers
19 views

Mixing liquids when applying a voltage

I'm thinking in the following experiment: A) Two (non mixable (like water and oil)) liquids are going to lie in a container, in the extremes of the container there are two electrodes, those ...
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36 views

problem about heat in thermodynamics

$$\nabla G=-T\nabla S-T\nabla S_{sur}=-Q+q $$ $$\nabla G=-T\nabla S-T\nabla S_{sur}=-(U-W_{rew})+q $$ $$\nabla G=-T\nabla S-T\nabla S_{sur}=-(q+W-W_{rew})+q $$ $$\nabla G=-T\nabla S-T\nabla ...
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49 views

Solving for the Nernst Potential in 3D

Hi guys I'm totally stuck on the following question: We know the ionic flux between two chambers due to uneven concentration can be computed by the Nernst-Planck equation $$j = -D_p \left(\nabla C ...
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58 views

Why are atoms with a complete octet the most stable ones? [duplicate]

I mean are the valence electrons in an octet arranged so that they have the lesser amount of energy that is lesser than electrons in other atoms?
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61 views

Linear decrease in temperature during a redox reaction?

This is physics-related, don't worry. To calculate the enthalpy change of a solution during a redox reaction, what we did in class was measure the temperature of the solution every 30 seconds (before, ...
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120 views

Milk-First School

I have always been struck by the huge amount of different arguments about the issue: When you make a cup of tea, the milk should be poured first or added to the cup after the tea? Wikipedia, ...
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28 views

How does Passivation in Mercury-arc-valve cause “diode” behavior

Does passivation of lead anodes cause them to become semiconductors? Or even become diodes (eg. a p-n passage)? How does this work on an atomar level? This question has been risen by trying to ...
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29 views

Covalent Bonds, Varities and Limits!

Related:http://chemistry.stackexchange.com/q/9459/ I was wondering, covalent bonds tend to share two electrons, apparently rarely more than three, and normally between two electrons. Can someone give ...