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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Physics behind blowing soap bubbles

Is it possible, using the surface tension of a soap bubble, to calculate the maximum pressure (created by the air flow) it can withstand while still attached to the orifice to prevent it from bursting?...
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84 views

How does electromagnetic radiations penetrate?

I am reading about the discovery of subatomic structure which includes all these things radioactivity, alpha rays, gamma rays, x rays et cetera. I read that electromagnetic radiations are energy ...
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48 views

electron shell jumping in Iron?

I understand a "little" about electron shell jumping, I was wondering about "Iron", If iron was heated to a gas, perhaps held in a vacuum maybe even under pressure, would the added energy make the ...
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71 views

Does chemical energy contribute to mass? [duplicate]

Does chemical energy contribute to the mass of an object? I don't mean the bond energy, but the possible energy that could be released (i.e. Does an atom of oxygen and a molecule of hydrogen (H2) have ...
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232 views

Is water steam in air a case of liquid in gas solution?

Thinking of this question, I thought that the phenomenon of water evaporation into the air is totally analogous to the solid (say, salt) that is dissolved into a liquid (water). Indeed, in this ...
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45 views

Why don't fire hoops blow out while spinning, but blow out when blown out?

My friend spins fire hoops and we're wondering why they don't blow out while she's spinning them, but do, when she blows them out one by one. I don't imagine there's so much more CO2 (so much less O2)...
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120 views

Energy of a system if the nuclear repulsion increases

I have calculated the optimised geometry for a molecule. I have noticed that the energy of the nuclear repulsion increases with each iteration of optimisation. What is the logic behind this?
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829 views

Correlation energy - is it the difference between the Hartree-Fock energy and exact energy, or Hartree-Fock PE and exact PE?

For some reason I can't find anything stating it either way explicitly. What I'm talking about is this. Is this difference referring to potential energies or just energies in general? I assume it's ...
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86 views

Is Boltzmann constant $k_B$ constant?

I heard in a lecture that Boltzmann constant $k_B$ is not constant in some special cases. Do you know the title of the article which contains this one? Do you think this idea is true?
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77 views

How to thermodynamically understand process of burning a piece of coal?

Let's imagine that I have a match in hand and nugget of coal on my desk. Then I light up the match and place it for few seconds near the coal so a tiny piece of nugget catches fire. Then another piece ...
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90 views

How does gas pressure increase the lifespan of Halogen tungsten lamps in the Halogen Cycle?

I am curious about this passage "Since quartz is very strong, the gas pressure can be higher,[5] which reduces the rate of evaporation of the filament, permitting it to run a higher temperature (and ...
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276 views

DFT Calculations, Atomic Ionization Potentials — Which Exchange-Correlation Functional to Use, to Preserve Koopmans' Theorem?

I have a program which can perform density-functional calculations for atoms, given a density functional. Of course the simplest form of exchange potential to use is one relevant for a uniform ...
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68 views

does there exists a rope such that it takes longer to burn the whole rope from one end? [closed]

And it takes less time to burn from the other end. The rope could be any of materials and structures and asymmetric. EDIT: But the external environment may not change during burning, and the way (eg ...
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180 views

Chemical potential in terms of temperature and pressure

For part (a), I know how to take the partial derivatives of S to get chemical potential, pressure. But there seems that I still need one equation to correctly express chemical potential in terms of T ...
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56 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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76 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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785 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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99 views

Calculate the required water for humidity [closed]

I'm not sure if this is the right place to ask. I have a humidifier, and a closed room. Basically, I want to know the required water to reach a certain level of humidity. My room volume is 42 meter ...
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130 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 ...
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652 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 ...
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483 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 ...
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62 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: ...
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55 views

Is it possible to make use of paper/bill permeate by chemical compound to became a paper-made bullet-proof vest?

Is it possible to make use of paper/bill permeate by chemical compound to became a paper-made bullet-proof vest? This is inspired by Greece and Italy tend to have more riot than rest of the Europe ...
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27 views

Where does the energy that release when bond is formed between two atoms come from? [duplicate]

When two atoms attracted to form bond, energy is released. But where does this energy comes from. Is this energy released when electrons goes to their ground state or somewhere else?
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18 views

Is the bond order in a resonance situation an average or can half bonds exist?

When drawing the lewis dot structure for $NO_2^-$ There is one double bond and one single bond so the molecule exhibits resonance and has bond order of 1.5. Does this mean the molecule shares 0.5 ...
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16 views

Adiabation Flame Temperature Overestimation (Hydrogen Gas)

I'm working on some code that computes adiabatic flame temperature given a balanced equation and the relevant thermodynamic properties and I'm starting with the simplest combustion reaction I can ...
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13 views

Is there a way to calculate the change in temperature of water in a vacuum?

My understanding is that water boils when the vapor pressure is reached and then, at some point, freezes. Is there a way to relate the vacuum pressure to the temperature of the water until it changes ...
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40 views

Why human body is not affected on magnetic field?

Electric-current easily cause shock to human body. But magnetic fluxs through human body do-not cause any perceptible change, as-well no invisible-impacts/ health impacts are well-known. We, when hold-...
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30 views

Question about the reaction quotients

I have a question connected with the reaction quotients. In another post (How to express the chemical potential at zero partial pressure?) it was revealed that the chemical potential of a substance is ...
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28 views

How to express the chemical potential at zero partial pressure?

Does someone know how to express the chemical potential at zero pressure? In the expression of the $i$th component $${{\mu }_{i}}=\mu _{i}^{\otimes }+\int\limits_{p_{i}^{\otimes }}^{{{p}_{i}}}{{{V}_{m}...
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54 views

Why does the Gibbs free energy not decrease ad infinitum?

I would like to ask which guarantees if the Gibbs free energy has a minimum in closed system (e.g. in a chemical reaction system) at constant pressure and temperature? Why does it not decrease ad ...
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26 views

Determining bond length of HCN using rotational constant (Physical Chemistry 2)

Context: 2nd year undergraduate student taking Physical Chemistry II. Question: Determine the HC and CN bond lengths in HCN from the rotational constants: B($^{1}H$$^{12}C$$^{14}N$) = 44.316 GHz B($...
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48 views

Copper density modification

Can you increase the density of a material surface (metal) by surface treatment? For example commercial copper. If we take the ordinary OF copper (99.95%), I would expect not to have the tabulated 8....
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25 views

Absorption spectra of molecules library

Do you know where I can find a library with absorption spectra? I would like it if then I could input a wavelength and get back a specific value. More specifically I would like to see the absorption ...
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51 views

Physical reason of adding salt when we're cooking rice (osmosis)

Why do we add salt when we're cooking rice? I know one reason is related to the boiling point of water but someone said it is also related to "Osmosis". What is the relation between adding salt and ...
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59 views

Velocity from the cumulative distribution function of the Boltzmann distribution

I want to get a Boltzmann distribution of the $v_x$, $v_y$ and $v_z$ velocity components (please, notice that the distribution is one-dimensional). To do so, I need the cumulative distribution ...
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10 views

Do the isotopologues of a compound affect it's cracking patterns in a residual gas analyzer?

For instance, CO2 is listed as 100% of the peak at 44, 11% of the peak at 28, 9% of the peak at 16, and 6% of the peak at 12. But now consider CO2 comprised of C13. obviously the peaks would be at ...
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31 views

Conformational Analysis of Ethane and Butane

How does a condensed matter theorist explain conformations of Ethane and Butane using tools from Quantum field theory? If they don't how do they calculate energy differences and predict differences ...
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55 views

Would it be correct to state that all the forms of everyday matter (mountains, tables, buildings, people, etc.) are in a metastable state?

We had a fire going in the backyard of a friends house this weekend, and after thinking about the chemical reactions occurring in the wood (and anything else we threw into the pit), I started to ...
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19 views

How strong is the HCN Union when modelling with springs

I'm modeling the HCN Molecule with springs, giving the bounds between H and C the name k1 and between C and N k2. Is there any information of how strong is the bound? We were asked to get the ...
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29 views

breaking bonds with light

Light, for instance green light (532 nm = 2.33 eV) has an energy comparable to that of many chemical bonds (C-C bond dissociation energy is about 3.6-3.7 eV). So how is it that I'm not being burned ...
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9 views

Butler-Volmer Anodic and Cathodic Activation Constant Proof

In the Butler-Volmer Equations, I have often seen the activation constant at the anode and cathode related by: $$ a_a=1-a_c $$ This is the relation used, for example, on plots of this equation on ...
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30 views

How did scientists calculate the number of atoms in one mole of a substance? [duplicate]

Please explain me about the basic methods about how can we calculate that 1 mole of a substance contains 6.022140857 × 10 23 molecules? Tell how the modern scientists calculated it and how Avogadro ...
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77 views

What would be the best material to reflect radio waves?

I was thinking about what would be needed to build a parabolic dish and I inevitably came to what material to use. From what I could gather after a quick search on the internet, it would seem that any ...
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23 views

Copper vs Tungsten (Diffusion)

I've been studying on how to compare the activation energy for (void-) diffusivity of Copper versus Tungsten. I ended up finding $E_a[cu] = 1.1[eV]$ and $E_a[W] = 5.2[eV]$ in literature where the ...
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1answer
48 views

Humidification Problem [closed]

Humidification Imagine that water is evaporating into initially dry air in the closed vessel shown schematically in Fig. 8.1-1(a). The vessel is isothermal at 25 C, so the water’s vapor ...
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45 views

calculating with quantum numbers and shape of nodal shells

I'm attending in a chemistry course now, and in the beginning we scratch the surface of the quantum physics, which have led me to some problems. Mostly I understand all what we get until now, but ...
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34 views

What happens when a semipermeable membrane allows only one solute to pass through?

I'm essentially a medical student where we deal a lot with osmosis. But when we are taught, it is done generally with only a single solute in consideration. What if two different solutes are used on ...
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24 views

Gibbs isotherm and calculating interfacial tension change from first principles

Question: Is it possible for a solid particle to change the surface tension between two phases? (or: Does a solid particle have a chemical potential?) This question stems from the more fundamental:...
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82 views

Calculate how many photons hitting a sample that are absorbed

In the determination of the quantum yield of a photoisomerization, $\Phi,$ the following is needed $$ \Phi = \frac{\mbox{Number of "reactions"}}{\mbox{Number of absorbed photons}} $$ The photon flux ...