Physical chemistry deals with the study of macroscopic and microscopic phenomena in chemical systems in terms of physical laws and concepts [thermodynamics, statistical mechanics, kinetic theory, quantum mechanics ...]. Some of the subfields that physical chemistry includes are: Quantum ...
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1answer
120 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?
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2answers
100 views
What are some major differences between physics and chemistry?
What are some major differences between physics and chemistry? I Know that they both study atoms, electrons and molecules.
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0answers
25 views
A quick method for separating liquids? [closed]
This is more of a chemical engineering question, but technically physics encompasses chemistry and engineering as well, so I thought I'd give it a shot before I get shot down, so to speak.
So-- ...
3
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3answers
169 views
Is Uranium renewable, or will this science fiction scenario become reality?
In my imagination, nuclear power could disapear when we use up all the uranium generating electricity, or exploding nuclear bombs.
Is uranium a renewable resourse? if not, can we prove that this ...
2
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0answers
42 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 ...
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1answer
35 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 ...
2
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1answer
66 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 ...
6
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3answers
105 views
Ionic vs Covalent bonds; dividing line?
I understand this is the Physics SE, but there isn't a Chemistry SE (yet) and there are some physics inherent in the question, so...
Backstory: When I learned about chemical reactions, there were ...
4
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1answer
94 views
How to know what materials are good conductors of electricity?
I'm not asking a question like "Is the wood conductive?". No. I'm asking what properties do they have to have to be good conductors. Theoretically I mean. Thanks.
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1answer
67 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 ...
0
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1answer
128 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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1answer
41 views
Which bonds are the cross-links and which are secondary bonds (in elastomers)? [closed]
Elastomeres are "defined" as:
"linear-chain polymers with widely spaced cross-links attaching each molecule to its neighbours"
Now I found sentences (talking about glass transition):
"This means ...
3
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0answers
67 views
What equation describes the electrostatic potential in these circumstances?
I have a solver for Poisson's equation and it works nicely. It uses finite differences. It works in the presence of multiple dielectrics.
It also solves the Poisson Boltzmann equation. That is, fixed ...
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1answer
95 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).
...
5
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1answer
93 views
Addition of a neutral electrolyte to water— how can it increase conductivity?
Sparked off by Is sea water more conductive than pure water because "electrical current is transported by the ions in solution"?
This question really belongs on chemistry.SE, which is ...
3
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1answer
119 views
How does a stronger magnet affect the MRI image quality?
In which ways is a stronger magnet better for magnetic resonance imaging? I read that:
The field strength of the magnet will influence the quality of the MR image regarding chemical shift ...
1
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1answer
225 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
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1answer
97 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 ...
3
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2answers
217 views
What meaning do changes in the absolute value of Gibbs free energy have in a simple expansion process?
Below is a simple representation of the thermodynamics of a steam turbine. Stream kinetic and potential energy changes are neglected and no other type of non-PV work is done besides shaft work. ...
3
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1answer
75 views
When do thermal and chemical equilibrium not coincide?
What is an example for a system, which is in chemical equilibrium, but not in thermodynamical equilibrium?
And what about the other way around?
It seems to me, that as long as Parameters like ...
3
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1answer
92 views
What does activation energy actually do?
Spontaneous (exothermic) chemical reactions often require a push from the addition of externally supplied energy. This energy is often called activation energy. What does activation energy actually ...
3
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1answer
91 views
Statistical Mechanics treatment of the reaction process?
I'm searching for an at least semi-rigorous Statistical Mechanics description/treatment of a (spatially resolved) chemical reaction process of a macroscopic portion of at least two different species ...
4
votes
1answer
198 views
Energy per particle vs. chemical potential vs. evaporation energy
There is a system of N particles. They interact and are bound together with a binding energy Eb (or potential energy). To characterize the system there are multiple terms
Energy per particle Eb(N)/N
...
2
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1answer
75 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?
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4answers
545 views
Why does the water rise?
It's a very popular experiment (eg), from elementary school : put a burning candle on a dish filled with water, cover the candle with an inverted glass: after a little while, the candle flame goes ...
2
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3answers
193 views
Nanorobots. What stops us from producing them yet?
If we can already predicts accuratelly motion on molecular levels, what stops us from developing small robots to, for instance, navigate through our blood vessels looking for cancerous cells and ...
1
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1answer
74 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 ...
4
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3answers
599 views
Is the Mendeleev table explained in quantum mechanics?
Does anybody know if there exists a mathematical explanation of Mendeleev table in quantum mechanics? In some textbooks (for example in "F.A.Berezin, M.A.Shubin. The Schrödinger Equation") the authors ...
7
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3answers
188 views
Is mass-energy conversion in chemical reactions experimentally observable
This is a common point of argument on internet forums. I think it is fairly well established theoretically that there is a very small amount of mass converted to energy in an exothermic chemical ...
3
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1answer
244 views
The 2011 Nobel Prize in Chemistry
As far as I understand a new pattern of crystal growth has been found experimentally. How does it relate to the known 2D and 3D nucleation and growth of crystals? The dominating theory of crystal ...
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0answers
35 views
Anyone Know Details About the New Nobel Prizes in Physics and Chemistry? [closed]
The physics prize seems to be in astronomy but, I guess, that falls into the realm of physics for the lack of a separate astronomy prize. The chemistry prize, however, seems to also belong to physics ...
1
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0answers
56 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:
...
3
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3answers
2k views
Why is the energy density of gasoline so high?
We sometimes play a game in my family whereby we trace the energy for a device back to it's source:
The Xbox got power from the wall.
The wall got power from the local transformer.
The transformer ...
7
votes
4answers
1k views
How was Avogadro's number first determined?
I read on Wikipedia how the numerical value of Avogadro's number can be found by doing an experiment, provided you have the numerical value of Faraday's constant, but it seems to me that Faraday's ...
4
votes
1answer
97 views
Voltage drop over a cell membrane
Again, a problem from exam preparation:
[A] cell's membrane allows sodium ions to pass through it, but not chlorine ions. The cell is placed in a salty solution with a ten times higher ...
0
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1answer
55 views
Circulate smoke in a closed system
Hey i am by no means a scientist but i have a idea for a art work using smoke.
Basically what i want to know is whether it is possible to circulate smoke by means of a pump through a transparent box. ...
2
votes
1answer
134 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 ...
0
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0answers
108 views
In Aerospace Salt Spray tests aluminum often gets covered in slime, what is this slime chemically? [closed]
When conducting MIL-STD-810, Method 509 salt Spray test many metals, but especially aluminum come out covered with slime. The slime usually dries to an easily removed powder. What is this slime? I ...
3
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1answer
195 views
Why is E85 less efficient than straight gasoline?
Why is straight gasoline (or whetever the mixture was before the introduction of ethanol) more efficient (ie, more miles/gallon) than E85? I've known since it's introduction that E85 was less ...
1
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1answer
582 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
3answers
184 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 ...
3
votes
5answers
695 views
Conversion of mass to energy in chemical/nuclear reactions
Is mass converted into energy in exothermic chemical / nuclear reactions?
My (A Level) knowledge of chemistry suggests that this isn't the case. In a simple burning reaction, e.g. $C+O_2\to ...
3
votes
1answer
159 views
Physical Chemistry: What's the relationship between orbital overlap and barrier shape?
This is a question for the physical chemists out there.
For a given chemical reaction there is a barrier to traverse in order to proceed from reactants to products. Reactants e.g. an organic base ...
2
votes
3answers
115 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 ...
1
vote
3answers
224 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 ...
2
votes
1answer
122 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
102 views
5
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1answer
159 views
What happens to chemical compunds that include radioactive nuclei, when those decay?
Say you have a chemical compound made up of one or more radioactive nuclei. If the nucleus decays, does the compound?
Possible outcomes I can think of:
the compounds continues to exist if a ...
3
votes
1answer
464 views
Chemical potential interpretation
Something that has bothered me for a while regards the interpretation of chemical potential for different statistics. While I understand its meaning in metals (and its relation with the Fermi ...
3
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1answer
150 views
determination of voltaic cell voltage
if i understood this correctly, the determination of voltage for a specific voltaic (gallvanic) cell is determined only by the chemical correlation between the two metals. is this true?
for an ...
