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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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Why can't a diesel engine burn petrol? [on hold]

On the Internet, I read that the self ignition temperatures of petrol and diesel are around $260$ and $210^{\circ}{\rm C}$ respectively. The difference is about $70^{\circ}{\rm C}$. The temperature at ...
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1answer
32 views

How many calories in a block of wood?

I was recently thinking about the human body and the energy we get from food. I understand we don't have the ability to properly digest certain things like stones and wood and grass, but if we did, I ...
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0answers
20 views

How to use Hund's third rule for excited electronic configurations?

Hund third rule states: For a given term, in an atom with outermost subshell half-filled or less, the level with the lowest value of the total angular momentum quantum number ${\displaystyle J\...
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0answers
17 views

Usage of pure substance chemical potential for the mixture of gases

There is a known expression relating the change in the Gibbs energy of the ideal gas to the change in pressure under the constant temperature $T$: $$\Delta G = nRTln\frac{p_f}{p_i} \tag{1}$$ where $n$ ...
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0answers
79 views

Is $H_2O$ the only compound which has a density anomaly? [duplicate]

My question is simple: are there any elements, compounds or materials other than water ($H_2O$) which have a density anomaly characterized by a turning point in the $T-\rho$ curve?
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1answer
14 views

Which elements or isotopes can be analyzed by Neutron activation analysis (NAA)?

Some sources name only a handful, but that might refer to the use of optical film. Others state more than 70. I would like to know which elemets or isotopes can be detectet/imaged by NAA.
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1answer
29 views

For the $\mathrm{H}_2$ molecule which spin states correspond to bonding? and which spin states correspond to anti-bonding?

Do I understand correctly? In the case of the $\mathrm{H}_2$ molecule, the overall state is $S = \Psi(r)\chi(s)$.....(Spatial and spin aspects) $\Psi(r)$ is inherently anti-symmetric under exchange ...
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2answers
41 views

Chemical potential and equilibrium condition

My question is about the $dG=0$ condition for the equilibrium in a system, say, solid + gas (water and ice, if you prefer). Almost every textbook gives the following recipe to understand phase ...
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1answer
37 views

Water Bottle Condensation

My friends and I were at a party last night and we were crushing empty water bottles until the cap popped off and water vapor came out. I have two questions regarding this phenomenon. From previous ...
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0answers
22 views

How many Vibrational degrees of freedom does a diatomic/triatomic linear molecule have?

I looked it up and found the formula to calculate number of vibrational degrees of freedom.I got it how they came up with this formula. It was (3N-5) where N stands for total number of atoms in a ...
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0answers
16 views

Why it is the Schottky defect not non stoichiometric?

Why Schottky defect doesn't counted under non stoichiometric defects? According to me since they lose atoms their stoichiometry must change.
2
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1answer
65 views

How do scientists experimentally (this means not theoretically) determine that an atom is not bonded with any other atom?

What I do not understand is how scientists can tell whether or not an atom is bonded to another atom or all by itself. If someone can help me understand this, please do.
3
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1answer
26 views

Why is it not possible to dope semiconductors with elements with 6 or 2 valence electrons?

As far as I have learnt, semiconductors are often made using elements from the 4th group, and their properties are often enhanced by doping with either pentavalent or trivalent elements. Take the ...
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2answers
53 views

Methods to convert nitrogen nuclei to oxygen nuclei?

Are there any "safe" method that allows converting the nitrogen into oxygen? There's Ernest Rutherford that uses alpha particles aimed at the nitrogen to create oxygen and hydrogen. But are there ...
3
votes
1answer
124 views

Why doesn't Coleman-Mermin-Wanger theorem contradict phase transitions in systems with 1D reaction coordinate?

How does both hold: Coleman-Mermin-Wanger theorem continuous symmetries cannot be spontaneously broken at finite temperature in systems with sufficiently short-range interactions in dimensions ...
3
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0answers
51 views

Why does bread sticks on a hot pan? [closed]

What causes a slice of bread when placed on a non stick (hot) pan without much oil/butter to stick to it. And why does it not in presence of butter or oil ?
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0answers
61 views

Time dilation in chemical processes [duplicate]

Imagine a piece of dynamite moving close to speed of light. Now it explode. How the blast will be observed from a stationary observer? Will it be spectacular slo-mo explosion? Will chemistry behave ...
0
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1answer
30 views

Döbereiner's Law Explanation Required?

I wanted to ask why do the middle elements in the triads have masses average to the other elements in the Döbereiner triads ?
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1answer
40 views

How To Calculate The Gibbs Energy Of A Molten Salt

If I have a molten salt of known composition, pressure, and temperature, is there a way to find the Gibbs energy of the substance? I'm not talking about the change in gibbs energy, I mean H-TS
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0answers
31 views

Stability of saturated energy levels

In The Feynman Lectures on Physics, Vol. 3, Section 15-5, there's a discussion of the stability of various benzene ions. It turns out that the ions for which the all the energy levels up to a certain ...
2
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1answer
45 views

Does corrosion of metals depend on electron degeneracy pressure?

Corrosion is about losing electrons for the corroded metal and gaining electrons for the oxidising substance. Is it correct to assume that what controls this process is the electron degeneracy ...
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2answers
61 views

What happens to the chlorine in epichlorohydrin when a two-part epoxy is air-cured?

Where does the chlorine go? Does it evaporate as a by-product or does it remain in the epoxy? I'm using a two-part resin and hardener and curing them at room temp. The resin is bisphenol-A-...
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0answers
31 views

Particle in a box as easy model for molecules

I am trying to use the particle in a box model as a simplified model to calculate the energy difference between HOMOs and LUMOs of a molecule. The molecule I work with is made out of n phenyl-groups. ...
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0answers
10 views

Formula of a non-stoichiometric compound from mole ratio

For example, in Simkovich, George. Transport in nonstoichiometric compounds. , it is given that the mole ratio of Cu and Fe is 1.33:1.00. From that the compound formula is written as Cu1.244Fe0.933S2....
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0answers
24 views

Why does the Anode and not the Cathode corode during eletrolysis of water into $H_2$ and $O_2$?

After experimenting with the production of Hydrogen from salt water, I kept on noticing that the Anode (-) gets coroded and not the Cathode (+). Is it perhaps that water in itself is a naturaly ...
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0answers
31 views

Under what conditions can molecules exist?

I am curious to know the conditions required for any two or more atoms to bond together and form a stable molecule. Is their a set of rules that should be satisfied?
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3answers
50 views

Is it possible to power a car with chemiluminescence? [closed]

Chemiluminescence means substances that in a reaction emit light. I wonder if such a reaction would be possible to power an electric car using an photovoltaic panel lighted by the chemical reaction?
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2answers
722 views

What is the source for Osmium's colour?

The majority of metals are known for appearing grey to our eyes, cf. e.g. Why are most metals gray/silver? But the main exceptions to this are the "famous" group eleven metals, where their distinctive ...
5
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2answers
211 views

Sodium sometimes absorbs orange-yellow light, sometimes emits it? Huh?

Usually, we are told that sodium emits orangish-yellowish light, which is why city streetlamps are that color. Now, I read in New Scientist magazine that exoplanet WASP-96b is bluish because the ...
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2answers
81 views

What happens if Jupiter is ignited?

I was wondering, what would happen if there was a large amount of oxygen released into Jupiter's atmosphere, than igniting it? Because Jupiter is 90% gas, therefore being a big fire waiting to happen (...
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0answers
16 views

Literature covering Hund's coupling case and anomalous Zeeman effect

I am taking a course in cold chemistry and different types of interaction seem to be an important cornerstone in the course. I am looking for a book that might cover the topics of molecules in ...
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0answers
19 views

What is the probability function for a molecule having energy in a certain mode, taking the minimum required quantum energy of that mode into account?

I understand that the probability density for a particular velocity v+dv in one dimension for a molecule in a system is: $$f(v) = \sqrt{\frac{m}{2\pi k_B T}} \cdot e^{\frac{-mv^2}{k_B T}}$$ I'm ...
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1answer
36 views

Why do the sun and planets differ in their chemical elements composition?

The chemical elements composition of the sun changes as its nuclear furnace changes elements into heavier ones. But it is supposed to be mostly Hydrogen at the start. The planets are too cold for ...
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2answers
535 views

Implications of parity violation for molecular biology

In biology, the concept of parity emerges in the context of chiral molecules, where two molecules exist with the same structure but opposite parity. Interestingly, one enantiomer often strongly ...
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1answer
28 views

Will a solution undissolve if left for a long time? [duplicate]

Simple questions: In a solution of NaCl (aq) that is unsaturated, will the Na and Cl ions eventually start collecting in the bottom of the container because of gravity pulling them down? OR Will ...
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2answers
55 views

Is it possible to break a carbon dioxide molecule using electromagnetic waves?

I'm no expert in physics, but I was just wondering if breaking apart $\rm CO_2$ into oxygen and carbon would be possible using certain electromagnetic wave?
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0answers
15 views

Surface Plasmon Spectroscopy - can you explain it better?

From what I understand, when you shine light onto a metal film in eg. Kretschmann configuration, the light of certain wavelength is coupled into plasmons (SPP) that propagate in the proximity of the ...
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0answers
36 views

When we mix water with H$_2$SiF$_6$ and boil them, how much of the H$_2$SiF$_6$ evaporates?

If water evaporates also at temperatures much lower then its boiling point, and so do, I believe, other liquids, how much H$_2$SiF$_6$ (boiling temp. 108 C) is to be found in the steam over boiling ...
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1answer
25 views

Seperating Charges in a Cell

Sorry for not being detailed for my question here but how do charges seperate in a cell and when the electrons are pumped out of the battery does it return and become positive ? Yet again sorry if I ...
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1answer
24 views

Are there other properties besides lower boiling point that make isobutane a better refrigerant than butane?

Asked differently, if -1C is low enough for the application is there any reason not to use butane rather than isobutane as the working fluid in a refrigeration system?
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0answers
19 views

The Stern-Volmer equation units

What are the units in The Stern-Volmer equation? For example if it is all about optical sensing of dissolved oxygen What could be quenching rate coefficient, luminence period coefficient, partial ...
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0answers
17 views

Can sonoluminescence happen using antibubbles?

From what I've understood so far about sonoluminescence, it's a process where sound waves create thousands of hot, luminous bubbles in water which produces light [1]. "When the sound field ...
3
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1answer
59 views

Would a very strong force of gravity make things break apart?

If I take an hammer and slam it on a table, I will not be surprised to see the table breaking and my anger slowly vanishing. I remember a difference being made between impact and non-impact forces ...
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0answers
19 views

Representing polypeptide in spherical polar coordinates in protein folding problem

I am trying to represent all the atoms of a protein polymer in spherical polar coordinates. However I couldn't capture the dihedral angle present in between successive polypeptide chain. How do i do ...
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1answer
22 views

Multi-stability potential is suitable for interdisciplinary branches of science?

The potential function $V(x) = c(x-a)^2(x-b)^2$ with constants $a,b,c$ and some variable $x$ has two minima: One at $x=a$ and another at $x=b$. When plugging this potential function in Newton's ...
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0answers
51 views

Why applying a force to something does not always result in an energy consumption? [duplicate]

I usually don't envy a simple table, but I'm a little bit concerned with why it isn't apprently wasting any energy while doing some "useful things". I'm not a physicist and I can't find an example ...
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2answers
24 views

Is the rate of evaporation in the below mentioned situation constant when liquid vapour equilibrium is not reached?

i am studying liquid vapour equilibrium and there is the set up (below) for the experiment.The conditions:temperature is constant throughout. in this case is the rate of evaporation of the liquid ...
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0answers
34 views

Chemical potential of solute in a saturated solution

It's been a while with my encounter with chemical potential. Now that I am studying a research paper, it somehow implies that the chemical potential of a solute under saturated solution (standard T, ...
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0answers
26 views

Making DIY Snow gun, particularly in mild climate (How to make snow)

I'd like to make snow, for fun. I want to know how to create snow with liquid water, how is snow made ? Do I need a specific temperature ? Atmospheric pressure ? Maybe the density, the velocity ? the ...
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0answers
30 views

Standard Gibbs - Temperature effects

The common teaching is that Gibbs Free Energy is calculated by the following: $$dG=dH-TdS$$ And: $$dG(T)=dH_o-TdS_o$$ Where $G_o$ is the Gibbs at a temperature 'T' and standard pressure/...