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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3answers
604 views
is it possible to flow current in open circuit?
First , i don't know much about chemistry and physics. I'm just a graphic designer but i have this question in my mind. I'm sorry if this question is too basic and use 'generic' language.
As i know ...
2
votes
1answer
187 views
How much water is destroyed in photosynthesis, relative to the world's supply?
Water is involved in the photosynthesis. How much water are we talking about compared with the total amount on water on Earth? Is it enough to have an effect on the average age of water molecules?
2
votes
1answer
114 views
THT (Tetrahydrothiophene) absorption spectrum
I am looking for the absorption spectrum of THT. What is the best way to find these types of exotic material's spectral characteristics?
2
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1answer
161 views
2
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1answer
147 views
Man on treadmill and energy/mass conservation
Suppose we put a very obese man inside a large air tight isolated room with a treadmill and he runs on the treadmill for 24 hours and at the end of the day he sees his weight has come down (mostly ...
2
votes
1answer
2k views
Why is oxygen in a triplet state and what are the consequences?
From Wikipedia here and here:
''Almost all molecules encountered in daily life exist in a singlet state, but molecular oxygen is an exception.''
''The unusual electron configuration prevents ...
2
votes
3answers
917 views
Widom-Larsen Theory
Does the Widom-Larsen theory pose a credible underpinning for Low Energy Nuclear Reactions, often incorrectly referred to as "Cold Fusion"?
http://arxiv.org/abs/cond-mat/0505026
2
votes
1answer
180 views
Electric dipole transitions/expectation value of position
Part of a homework question asks to show that for $\ell=0$ in both $\Psi_i$ and $\Psi_f$, we have
$$
\int \Psi_i^\ast \vec{r} \Psi_f \; d\tau = 0
$$
for the position vector $\vec{r}$. (This is for ...
2
votes
1answer
457 views
How specifically do emulsifiers work?
I'd like to understand better how emulsifiers prevent droplet coalescence. There must be something more they do than just lower the surface tension between the droplet and the ambient substance. I ...
2
votes
1answer
164 views
Is it possible to mechanically isomerize an sp3 hybridized carbon center?
Imagine I have an sp3 hybridized carbon attached to four separate polyethylene chains. By pulling on the polyethylene chains in some manner, is it possible for me to mechanically isomerize the chiral ...
2
votes
1answer
43 views
Reason behind cohesive and adhesive force
What is the real cause behind the cohesive and adhesive forces?
2
votes
2answers
75 views
Driving a solution of optical isomer molecules with the resonant frequency
What happens when we drive a solution of optical isomer molecules (enantiomers) with a microwave radiation in resonance with the tunneling frequency of the molecules (the frequency of the transition ...
2
votes
3answers
191 views
Air Regeneration in Closed Systems
I wonder what's the way to regenerate O2 in air without using consumable chemicals (where one can use electricity through electrolisis or using UV lamps)?
We can dissolve water into O2 & H2, but ...
2
votes
1answer
184 views
Vapor pressure higher than equilibrium vapor pressure
Is there any mechanism by which the vapor pressure of a liquid substance (lets say in a vacuum) is measured to be greater than the expected saturated vapor pressure at that temperature?
Specifically, ...
2
votes
1answer
415 views
What is the mechanism of dielectric saturation?
It is known from experiments that the dielectric constant of a solvent might decrease in regions where there is a strong electric field, for example, near a highly charged ion in an infinitely dilute ...
2
votes
0answers
85 views
Dissipation when the temperature is not constant
Consider a process where some chemical species diffuses from one part of a system (which I'll call $A$) to another ($B$) at a rate $r$ $\text{mol}\cdot \mathrm s^{-1}$. If the system's temperature is ...
2
votes
0answers
360 views
Equations describing the liquifaction of gases
I would like to find out how much energy is required to liquify gases (oxygen or nitrogen, for example). What are some relevant equations?
I'm curious whether creating small quantities of dry ice or ...
1
vote
3answers
314 views
The “binding energy” of bonded particles adds mass?
This is a follow-up my previous question. Several of the answers indicated that the mass of a particle (atom, proton, etc.) increase with the "binding energy" of it's component particles - the energy ...
1
vote
3answers
125 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:
...
1
vote
2answers
431 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, ...
1
vote
3answers
296 views
How would steel degrade in space
If there is a steel plate floating in space, for ever, within the solar system, how is it going to degrade? Of course without oxygen it is not going to oxidize (rust), but how are cosmic rays, UV ...
1
vote
2answers
75 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 ...
1
vote
1answer
490 views
Why does burning magnesium explode when sprinkled with water?
Magnesium powder burns extremely well and reaches temperatures of 2500°C. However, attempts to extinguish such a magnesium fire with conventional water (e.g. from a garden hose) only make it worse: ...
1
vote
1answer
113 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 ...
1
vote
1answer
1k 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).
...
1
vote
2answers
153 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 ...
1
vote
1answer
1k views
What is the approximate electrical conductivity $\sigma$ of graphene in S/m or S/cm?
I am trying to find an approximate value of the electrical conductivity $\sigma$ of graphene in units of S/m or S/cm. This table on Wikipedia gives $\sigma$ values for a variety of materials ...
1
vote
1answer
120 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 ...
1
vote
1answer
667 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 ...
1
vote
1answer
95 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 ...
1
vote
1answer
2k 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 ...
1
vote
1answer
994 views
Obtain oxidation numbers from looking at electron configuration?
Suppose I know that Selenium has electron configuration $[Ar] 4s^2 3d^{10} 4p^4$.
How can I use this information to then come to the conclusion that its possible oxidation states are 6, 4, 2, 1 and ...
1
vote
1answer
62 views
How fair is it to say that all chemistry arises from failures of the ideal gas law?
I was reading here about how the ideal gas law assumes point masses and non-interaction. Is it fair to say that all chemistry arises from failures of that?
Of course, such a sweeping generalization ...
1
vote
0answers
59 views
What's the underlying particle physics of endothermic reactions?
I don't just mean reactions that require heat to proceed, storing surplus energy in chemical bonds. I wonder about strongly endothermic reactions that suck heat out of environment.
You take some ...
1
vote
0answers
28 views
Half-Life Question [duplicate]
Possible Duplicate:
How do we know that some radioactive materials have a half life of millions or even billions of years?
I understand how to calculate decay, but it seems to me that the ...
1
vote
0answers
63 views
Are metal modes mixed with molecular modes during surface enhanced Raman effect?
This question is dedicated to Martin Fleischmann (1927-2012).
When a molecule is adsorbed on a metal surface, the Raman scattering amplitude from the molecule is enhanced. According to Wikipedia, the ...
1
vote
0answers
38 views
Why the dangling bonds at the edge terminated by hydrogen atoms give no contribution to the electronic states near the Fermi level
How about changing H atom to other kinds of atoms?
1
vote
0answers
62 views
Chemical reaction as state transition?
When considering diffusion of chemicals, the reaction part is business of chemical kinetics, where the relevant characteristics of different substances come from collision theory together with some ...
1
vote
1answer
77 views
What's the common consensus on the meaning of “physical change”?
I'm doing a textbook problem that shows a "molecular level" view of some matter, little colored balls, before and after, and there are, among the four questions, two that say: 1) Did a physical change ...
1
vote
0answers
80 views
Calculating the required amount of acid/base to reach a pH [closed]
Bit stuck on working this out - or if it is even possible.
I have a reservoir of solution (water/plant feed/dead flies) that is pH 6 and I want to get it to pH 6.25. Here is the information I have:
...
0
votes
2answers
233 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 ...
0
votes
2answers
3k 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?
0
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1answer
46 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 ...
0
votes
2answers
49 views
What is “species” in the context of an electrochemical cell?
From the Wikipedia entry on Electrochemical cell (http://en.wikipedia.org/wiki/Electrochemical_cell):
An electrochemical cell consists of two half-cells. Each half-cell
consists of an electrode, ...
0
votes
1answer
97 views
Electrical Resistance and chemistry
Can some one describe or explain what happens when too much current is passed through lets say a copper wire, I am looking for an explanation to do with physics and chemistry.
For instance we have ...
0
votes
2answers
283 views
Why are the alkali and alkaline earth metals present in the ashes of burnt wood? [closed]
The alkali earth metals form the two left-most column of the periodic table of the elements, other than hydrogen. See wikipedia articles:
http://en.wikipedia.org/wiki/Alkali_metal
...
0
votes
1answer
91 views
Chemical Equilibrium - Why do changes in pressure cause a shift in the ratio of products and reactants?
I understand Le Chatelier's principle and how every change to an equilibrium system causes an opposing reaction from the system. I also understand how, when pressure is increased, the equilibrium ...
0
votes
1answer
79 views
What's the vapor pressure and evaporation enthalpy of a saline solution?
Suppose you dissolve an amount of salt in water. Because of the attraction between the ions and the water molecules, you'd expect lower vapor pressure and higher enthalpie, both depending on the ...
0
votes
2answers
238 views
How does one calculate the volume of a nucleus and the volume of an atom (in this case hydrogen)?
The hydrogen atom contains 1 proton and 1 electron. The radius of the proton is approximately 1.0 fm (femtometers), and the radius of the hydrogen atom is approximately 53 pm (picometers).
0
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1answer
49 views
Action on Lard Oil
If water is mixed with lard oil and heated (creating some super-critical liquid with water), how does this affect the volatility of the mixture in comparison with its purity..?
So, My question is: ...
