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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34 views

How does the process of protein denaturatation work? [on hold]

I know it's the proteins that somehow change their properties at some temparature. But what kind of change, in terms of molecule-level structure?
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0answers
19 views

Thermodynamics Assignment: Combustion [on hold]

Acetylene, Methane and Octane are burnt in air (75% Nitrogen, 25% Oxygen) and forms Carbon Dioxide, Carbon Monoxide, Nitrogen and Water This is the unbalanced equation: C2H2 + CH4 + C8H18 + O2 + N2 ...
4
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2answers
242 views

Frequency of touch, taste, and scent [closed]

So I was thinking about sound - and how anything below 20Hz is basically inaudible to humans (because it is too low of a frequency to be recognized), as well as anything above around 20KHz (because it ...
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0answers
23 views

Saddle point and transition state of a molecule

During a transition of a molecule from one state to another, it pass through a transition state. This transition state, mathematically speaking, is a saddle point. That means, the second derivative ...
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1answer
21 views

Why is the objective function used in Nudged Elastic Band method reasonable?

In Nudged Elastic Band (NEB) method, which is used to find reaction pathways when both initial and final states are know, an objective function is first constructed and then minimized to find reaction ...
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0answers
15 views

Calculate Avogadro's constant based on grating constant and density of NaCl crystal [closed]

The tittle says it all. I need to calculate Avogadro's constant based on grating constant of NaCl crystal ( in this case 278 micrometers ) and crystal density ( 2.1 grams per cubic centimeter ).
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1answer
31 views

Is there any scientific instrument right now to monitor complicated chemical reaction between atom? [closed]

What is some differnt way to use any scientific instrument right now to monitor complicated chemical reaction between atom??
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2answers
52 views

Is there anyway to use a scientific instrument to measure the density of electron around the atomic orbital?

Is there anyway to use a scientific instrument to measure the density of electron around the atomic orbital? Please list both old way and more modern ways.
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0answers
40 views

Debye Hückel Theory valid for ions?

I am wondering about the following: Is Debye Hückel Theory only used if you look at how an external "strong" field(like a potential by a sphere that has a charge that is 1000times higher than the ...
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2answers
141 views

Why does ice melts, waits for 100 degrees and THEN vaporises? Why is not the process of expansion of things continuous?

What I am asking is this: Why can't a body be solid, then solid-ish, then solid-like, then liquid-like, then liquid-ish, then liquid, then vapor-like and then vapor? Why is there a rigid temperature ...
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5answers
2k views

When I stretch a rubber band, it breaks. When I hold the broken ends together, why doesn't it join again?

The question is simple. When we join the two broken surfaces, what is it that keeps the surfaces from connecting with each other, while earlier they were attached to each other? Also, would the two ...
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2answers
82 views

Acer saccharum (Sugar Maple) Sap & Freezing

This may or may not be the appropriate scientific discipline to ask this question of, but I'll give it a shot. I'll happily invite chemists to chime in as well. It's time to tap sugar maples in the ...
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1answer
39 views

Thermodynamics of zinc chloride to zinc

I am trying to deposit zinc metal from zinc chloride using chemical vapor deposition. But it is thermodynamically feasible to obtain zinc from zinc chloride?
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0answers
91 views

What is the most stable nuclide of an isobar?

From the semi-empirical mass formula, the mass of an atomic nucleus is $$M\left(A,Z\right)=Zm_p+(A-Z)m_n-\frac{E_b(A,Z)}{c^2}$$ I've been told (at first) that for a given mass number $A$, the most ...
1
vote
1answer
98 views

Why is a wine glass shaped the way it is? [closed]

Why is a wine glass shaped the way it is? And why are there different shapes for different wines? Is this a tradition, or is there any scientific reason behind it?
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1answer
69 views

Apparent color of flame as superposition of spectral lines?

In some cases one can identify a substance by the color emitted as it burns in a flame. A green flame might indicate the presence of copper. So here is the question. If we know wavelength and ...
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0answers
73 views

What are characteristic ranges of time, distance, energy regions for physics and chemistry? [closed]

I've constructed such table from many different sources for my thesis introduction: I'm trying to make a bit of philosophy it the thesis first chapter. Are they realistic or not? Could you make any ...
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1answer
45 views

What happens to gas molecules after Ionization?

I know that gas molecules conduct electricity after they get ionized but what will happen if we keep increasing the voltage even after ionization? Will it explode? If it will then how much energy ...
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2answers
52 views

How do you know which atoms are in a specific piece of matter?

If you have a piece of matter in front of you, how can you know of which atoms it consists? And starting from nothing, how can I discover all the elements (or just a lot of them) of the periodic ...
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2answers
69 views

What is this form of notation called?

$$^{14}_6C \rightarrow ^{14}_7N + E^{-} + \bar{\nu}_e$$ Just curious!
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1answer
105 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 ...
2
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2answers
137 views

What force creates ions out of neutral atoms?

Consider the reaction between Na and Cl to form NaCl. Na loses an electron and "gives" it to Cl because this makes both atoms more stable. But what forces "pulls" the electron from Na to Cl? Both ...
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1answer
92 views

why do we Carbonate drinks not any other gas

Carbonation is done in all fizzy drinks. Also it forms a small amount of carbonic acid which we feel on our tongue. We can diffuse oxygen as well in the water at higher level. Except for acid ...
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4answers
139 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 ...
1
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1answer
82 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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3answers
106 views

Atoms and electrons?

Consider a copper atom. If you place an electron near it, the protons in the nucleus would attract it like they attract the existing electron in the valence shell. However the electron you placed ...
3
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1answer
38 views

What is the origin and nature of the “hydrogen envelope” located on the sun side of a comet coma?

It is tempting to assume the origin of the hydrogen is water vapor from the comet, in which case, what process "breaks up" the water molecule (or perhaps ammonia molecule?)? Is the hydrogen actually ...
5
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1answer
276 views

Can a saltwater solution conduct electricity forever? [closed]

We know that very pure water does not conduct electricity, but salt water is a decent conductor. This is commonly explained by saying that "the ions carry the current through the solution", an ...
2
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0answers
46 views

High Young's Modulus and Tensile Strength of Carbon Nanotubes

I was recently reading about Carbon Nanotubes having extremely high Young's moduli, as well as high Tensile Strength, making them very interesting fibers. However, when I read this I wondered what was ...
2
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1answer
72 views

Does salt $NaCl$ as a solid float in molten salt?

I know ice floats in water because it's crystalline structure causes $H_20$ solid to be less dense than $H_20$ liquid. Is the same true for salt because it is crystalline? If not why?
7
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1answer
83 views

Does an electric field create a pH gradient?

Since pH is a measure of the effective concentration of $\mathrm{H}^+$ ions a solution, I expect that an electric field applied to a solution will create a pH gradient. The higher concentration of ...
3
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2answers
104 views

How to determine what an object is composed of?

Heads up: This question has never been asked (here) before the way I will ask it here, so let's shed some light on it a bit. Prelude and anecdote(can be skipped): The other day I was walking home, ...
2
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1answer
105 views

Absorption of a gas into a solid

When a gas interacts with a (crystalline) solid, some scenarios may happen: scattering: gas atoms will not stick or penetrate (do not interact with the solid) Adsorption: gas atoms stick to the ...
2
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1answer
56 views

Change of heat capacity fluid when you add solvent

I am considering a liquid for which I know $C_p$ or $C_v$. I am wondering how this changes when you add a (minor) amount of solvent to the liquid. Is there a general theory around describing how a ...
1
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1answer
129 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 ...
0
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1answer
133 views

Burning VS Melting: What is the relation in the atomic/molecular structure?

This has never been asked before on this site, so I thought I would ask this to help future searchers, passerbys, or others understand this better. What are the key differences between burning ...
1
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1answer
114 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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1answer
132 views

Are valence electrons in nonpolar molecules localized/delocalized?

Are valence electrons in non-polar molecules localized or delocalized? I'm quite confused about the whole electron localization and delocalization business. I'd love a simplified explanation that a ...
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5answers
278 views

What laws (formulas) govern forces between atoms?

What laws (formulas) govern the fundamental forces of nature? For example, gravity is governed by the inverse-square law. I am thinking about how particles attract each other, but also repel. All ...
4
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1answer
245 views

Can we model Chemical Reactions using Quantum Mechanics? If so, what is the most complex reaction we can model?

Not a physicist or Chemist, just interested in QM and it's applications. I've been reading lately about Quantum Chemistry and it occurred to me that since we can model electron orbitals in QM and ...
6
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1answer
149 views

Why can we skate on ice? [duplicate]

I have known the reason why skate can slide over ice is that water's melting curve in terms of pressure and temperature has a negative slope. If the pressure due to our mass increases sufficiently ...
0
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0answers
19 views

Specific Gravity vs. Pore Space in Chromatography Column

Wondering if we can apply molecular specific gravity to elucidate average time required to pass through a column given porespace, distance and viscosity? This would eliminate the need for special ...
2
votes
2answers
127 views

Temperature of thermochemical reaction between propane and nitrous oxide

I'm trying to calculate the properties of the combustion process using propane and nitrous oxide. When I tried to nail down the combustion temperature, the result looks just off to me. I went through ...
3
votes
1answer
340 views

Diffusion of gas in a liquid with changing pressure and solubility (chemical potential)

Modelling the diffusion of a gas dissolved in water in a vertical column of water, several meters deep. Also assuming the water is completely still, so only diffusion plays a role. (Actually a model ...
1
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1answer
101 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 ...
2
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1answer
77 views

Why does bringing N 1-orbital atoms together yield N levels?

A common example of this is that when bringing N hydrogen atoms together into a ring. Far apart, assume each electron exists in the 1s state. As we bring them together, instead of each electron ...
7
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2answers
1k views

Why does ice have a lower density than water?

Can someone explain me why is ice lighter than water? As I know, all solids are usually heavier than the liquids (correct me if I am wrong).
3
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1answer
56 views

Force field for Calcium ions, potassium ions and water in molecular dynamics

I want to adapt my existing MD simulation so that it can handle these three species. For the interactions of the ions I thought that I would use the coulomb potential, but I don't know what sort of ...
4
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2answers
233 views

Why do some things crystallize? (And others don't, for that matter.)

Ice, for example, will form a crystal when frozen under certain circumstances. Why is this the case for ice? While on the subject of water crystallization, why do snowflakes usually form in base 6 ...
2
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0answers
55 views

generation / destruction of fermions by phonons

my Hamiltonian consists of 1D free fermions coupled to a bosonic bath. The interaction is dictated both by scattering terms $H^{scatt}=\sum_{kq}\alpha^S_{kq}c^\dagger_kc_{k+q}X_q+h.c.$ as well as ...