Study of macroscopic and microscopic phenomena in chemical systems in terms of physical laws and concepts [thermodynamics, statistical mechanics, kinetic theory, quantum mechanics...].
3
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1answer
391 views
Energy levels in disordered organic semiconductors?
Now in disordered organics, the band picture is thrown out the window, from what I can tell (due to lack of symmetry). But don't HOMO/LUMO levels basically take the place of conduction/valence bands ...
2
votes
3answers
831 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
194 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
118 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
votes
1answer
163 views
2
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2answers
74 views
How to estimate the physical size of a molecule?
I'm reading some chemistry-related papers that employ concepts of droplet evaporation. Since I am no chemist, I am wondering:
How can I estimate the actual size of a molecule, say succinic acid?
An ...
2
votes
1answer
149 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
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
464 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
166 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
53 views
Reason behind cohesive and adhesive force
What is the real cause behind the cohesive and adhesive forces?
2
votes
2answers
78 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
196 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
186 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
444 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
89 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
361 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
327 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
142 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
480 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
301 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
42 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 ...
1
vote
2answers
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
2answers
76 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
557 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
117 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
161 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
122 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
715 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
1k 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
0answers
27 views
Determining the properties of an alloy
I am making a game in which the player will be able to create any possible alloy of metals. However, I need to find a way to determinate the properties of these alloys given the properties of the ...
1
vote
0answers
57 views
Chemical Equilibrium - Why does changing the temperature shift the equilibrium? [migrated]
I know that raising the temperature in a reversible chemical reaction causes the equilibrium to shift to the endothermic side.
I know that $\Delta G = \Delta H - T \Delta S$ but I don't know how to ...
1
vote
0answers
20 views
Solution of multiple materials
Introduction
I'm trying to make some strawberry liqueur. The recipe I got says I should put alcohol, strawberries and sugar in a bowl and leave it soaking for 4-5 weeks. I read that making liqueur is ...
1
vote
0answers
64 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
337 views
Is there any reproducible tested evidence for Ni-H cold fusion?
The main replications of cold fusion, the ones that are beyond reproach, used Pd/d as the system. But commercial developers have often claim to use Ni-H to achieve similar effects. The claims include ...
1
vote
0answers
65 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
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0answers
40 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
63 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
91 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
81 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
236 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
votes
2answers
39 views
A question on lewis model [closed]
Electron affinity of chlorine = -349 kJ per mole. And, first ionization energy of sodium = 496 kJ per mole while energy required for combining= 147 kJ per mole.
Isn't it a contradiction against ...
0
votes
1answer
63 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
54 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, ...
