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Questions tagged [physical-chemistry]

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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Concept of polarization in microwave rotational spectroscopy

I am trying to understand the concept of polarization of molecules after they are excited by a microwave pulse. The context is: The complexes are produced in a pulsed supersonic jet expansion of a ...
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1answer
33 views

Theoretical physics for better batteries?

It is Earth day, so I started thinking about the theoretical physics problems that could help reduce greenhouse-gas emissions and fight climate change. We actually have a reasonable range of ways to ...
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1answer
31 views

What would happen if you dropped a stick of dynamite from a high place?

If you were to drop a stick of dynamite from a high place, what would happen once it hit the ground, and why?
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1answer
39 views

Was it ever experimentally verified whether antimatter can form chemical bonds the same way matter does?

It's "common knowledge" that antimatter only differs from matter in its charge, and if left alone, it would behave exactly as matter does. This would infer that atoms of antimatter would form similar ...
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1answer
12 views

Do different liquids have different distributions of kinetic energy of their particles, and does this influence their vapor pressure significantly?

This is a bit of a cross-over between a physics and a chemistry question. When we say a liquid has temperature $T$ we make a statement about the mean kinetic energy of a particle in that liquid. That ...
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2answers
54 views

Why is gaseous carbon dioxide transparent? [on hold]

Some carbon-heavy products of combustion, e.g. soot, are black, as is carbon in other forms, e.g. graphite. This seems to suggest that carbon is black. But then how can $\text{CO}$ (carbon monoxide) ...
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19 views

Branch of Physics that Examines Atoms Relationships

Is there a specific branch of physics that can examine and calculate the strengths of atomic or molecular bonds and predict how they are going to break, putting into consideration the surrounding ...
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5 views

What molecular distribution models apply for nonequilibrium systems as cold stars?

Maxwell-Boltzmann distribution function describes well the distribution of ideal particles in thermal and chemical equilbrium (the concentration of the species is constant). Which models would apply ...
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1answer
51 views

Red colour of the Great Red Spot

In Wikipedia it is mentioned: "It is not known exactly what causes the Great Red Spot's reddish color. Hypotheses supported by laboratory experiments suppose that the color may be caused by ...
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0answers
29 views

Does the relation between energy and mass, proposed by Einstein hold true for all forms of energy? [duplicate]

I don't have a strong chemistry background, but I recently stumbled upon an answer that concluded that when supplying a reactant(s) with energy E it should be that the difference between the masses of ...
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1answer
32 views

ABS Latent Heat of fusion

I am looking for the latent heat of fusion for ABS Plastic (or at least an estimate). I can't find it anywhere online, or my 1983 copy of CRC handbook of physics and chemistry. I was able to find in ...
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1answer
579 views

Does soap repel water?

Yesterday when I was taking my bath, I scratched my soap bar a bit and threw that bit on the shower floor. There was a little amount of water on the floor where that soap bit fell. To my surprise, I ...
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1answer
80 views

Why microwave oven makes dried bread soft?

This is an old age trick: if you have some bread that became dried and you put it in the microwave few tens of seconds (10 to 30 for top results) you get a nice soft and warm loaf as if it just came ...
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23 views

Explain how chemical bond energy is ultimately converted to electrical energy

I can understand how a cell develops emf, why the electron flows between the battery terminals. I do not understand, How the chemical bond energy is transformed to electrical energy? What are the ...
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1answer
29 views

Why is an electrodes standard reduction potential does not depend on amount of chemicals?

The standard reduction potential is fixed for the type of chemical reaction. Why is it so? Why is an emf of a cell or an electrode's Standard reduction potential does not depend on say, quantity of ...
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3answers
137 views

Natural log of 2 in Radioactivity half life?

How exactly was the half life equation $\frac{ln2}{\lambda}$ derived? My book states something about integrated rate laws but doesn't really explain anything. Sorry, this is my first post in Physics ...
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0answers
35 views

Converting a discrete statistical energy distribution to a continuous version

The probability of finding a particle at a particular energy level when energy is considered discrete is according to Boltzmann: $$P(E_j) = \frac{g_j\cdot e^{-\beta E_j}}{\sum_{j=1}^\infty g_j \cdot ...
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1answer
42 views

When we burn a wood it burns with flame although it do not contain any gaseous substance [duplicate]

In books it is given that flame is only produced when gaseous substance burn but when dry wood is burnt it also burn with flame.why.
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2answers
87 views

Temperature as function of $CO_2$

The carbon stored in fossil fuels must have been taken out of the earth atmosphere from CO2 in past periods by plants. Thereby reducing the amount of CO2 drastically and increasing the amount of O2 to ...
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1answer
68 views

How to calculate the mass of gas needed to fill a cylinder to a certain pressure?

I m tasked with a tricky situation. I need to calculate the exact amount a tank can take in gas. But I dont know the volume of the tank. I just need to make sure that the tank reaches the right ...
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1answer
53 views

Why do the wavelengths of lights oscillate wrt atmospheric penetration?

Funnily enough, I was reading about Jungian Archetypes when I happened upon this diagram: I had not previously seen this and I couldn't find much information on it nor why it is occurring, I'd ...
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6answers
2k views

Conservation of Mass and Energy [duplicate]

I was thinking about some physics (relativity in particular), when it suddenly occurred to me that all my life I had been balancing chemical equations assuming conservation of mass, but I was ...
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0answers
41 views

Faradays constant determination? [closed]

I am a bit confused on how faraday determined his constant. So I’ve been taught that he realized that if you sent a certain amount of charge (96485 C), then one mole (or some fraction of that based on ...
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1answer
29 views

Selection rules in rotational spectroscopy- water molecule

The University of Liverpool maintains a ChemTube 3D page, where it says http://www.chemtube3d.com/spectrorotcd0-CE-TEST-ROTATE-ALL.html *> Highly symmetric polyatomic molecules, such as carbon ...
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0answers
45 views

Why is absorbance calculated as $\log_{10}(1/R)$ and not $1-R$?

According to Lambert Beers law, the absorbance ($A$) of a sample at a given wavelength can be described in terms of its transmittance ($T$) according to: $A = \log_{10}(1/T)$ In near-infrared ...
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1answer
32 views

Is there a definition for describing nuclear material undergoing fission/fusion? [closed]

Is there a term similiar as a piece of coal burning as ambers? Can nuclear material undergoing the reaction be transported?
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3answers
109 views

Why is methane considered an important greenhouse gas?

Methane’s absorption bands are centered at 3.2 and 7.2 microns -- far off the peak of the Planck spectrum for a 290 K blackbody near 16 microns. Moreover, its absorption bands overlap with the water ...
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2answers
45 views

If one divides the molecular dipole of HCl by the interatomic separation, the result is not a multiple of the electron charge. Why is that?

I'm having some trouble understanding the reasoning behind the final note in the following worked problem: An HCl molecule has a dipole moment of $3.4\times10^{-30}\:\rm C\:m$. Assuming that equal ...
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1answer
107 views

Time evolution of molecular signal from a laser-induced plasma - finding the right model for my data

I am looking at molecular emissions in laser-induced plasma plumes created in argon at reduced pressure (in the mbar range). To be precise, these are heteronuclear diatomic molecules that emit ...
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0answers
29 views

Mathematical Resolution of Overlapping Signals

I would like to take the opinion of physicists (my area is chemistry). During instrumental analysis, the output is a instrument response vs. time. Each peak corresponds to a molecule which is ...
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1answer
43 views

Why are there less bubbles the second time I pour soda in the cup?

I poured some Pepsi into a mug, and it foamed, and I poured until the foam was at the top of the glass. I waited a few seconds for the bubbles to go, and the liquid level was revealed to be at around ...
2
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1answer
28 views

Specific Heat, Conservation of Energy, and Kinetic Energy

Different molecules have different specific heats, such as water, which has a very high specific heat due to strength of inter-molecular attractions. If temperature is the random kinetic energy of ...
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2answers
56 views

Finding partial molar volume from an algebraic expression

I'm given the equation $ V = 120X_1 + 70X_2+X_1X_2*(15X_1+8X_2)$ and told to calculate $\bar V_1 $ & $ \bar V_2$ and then to show that $ V = \Sigma_i X_i*\bar V_i$. Since there are two mol ...
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1answer
83 views

Why hot soup is tastier than cold soup? [closed]

My physics teacher recently asked me this question. Can anyone answer the question?
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4answers
61 views

Bicycle Fuel equivalent on l/100km

Is there a way I can calculate the equivalent how much a Human powered bicycle consumes in the equivalent l/100 Km of Diesel fuel? And also can I calculate the same for Gasoline fuel? And for ...
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0answers
44 views

Van der waals forces interaction

My slides say: A gas with low density in which you can consider the attractive energy the sum of the isolate atoms couple $$ u=\int^S_\sigma{4\pi\frac{N}{V}}\left(\frac{\beta}{r^6}\right)r^2\...
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11answers
7k views

Are there physical properties that can be used to differentiate stainless steel from copper in a home environment? [closed]

So the backstory is that I purchased a reusable drinking straw that is copper coloured, but is advertised to be stainless steel. That got me thinking about whether I could be sure it was one or the ...
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0answers
13 views

Bond Nature of a comound [closed]

How can we determine the type of Bond in LiBaPO4? can we find out the nature of bond through charge transfer values of these elements? if yes then how?
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0answers
50 views

Gibbs free energy the 3 equation confusion

Hello can you please help me with thermochemistry? I have been taking chem classes since highschool and they ALL talked about Gibbs free energy, enthalpy, and entropy... even in college I got away ...
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0answers
38 views

Why hydrogen bond forming has lifetimes on picosecond scale?

According to this Research http://www.kinetics.nsc.ru/mds/downloads/2009_JSC_Naber_Vol_LifeTime.pdf hydrogen bonds are formed and destroyed within a timescale of a few picoseconds. Why hydrogen ...
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1answer
29 views

Nucleus in the wires

Can someone explain why we consider the electrons to move through a wire and not the nucleus? Couldnt atoms get ionised with losing a proton?
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14 views

Potential energy of molecule [duplicate]

Does potential energy of molecule and therefore bond length change with temperature?
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0answers
23 views

Bond energy and tempetature

Does bond energy depend on temperature? Also why is it defined at 298 Kelvin if some substances cant be in gas phase in that temperature?
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0answers
37 views

Why are(n’t) rechargeable batteries damaged by partial charging?

Originally asked in ElectricalEngineering.SE, but I was told Physics.SE might be a better place to ask. Over the years, I've come across websites and people with different opinions on the "correct" ...
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1answer
31 views

How will the Big Rip affect chemistry and nuclear interactions?

The "Big Rip" is a theoretical scenario for the death of the universe. Let's assume that this scenario is true. What can we expect to happen to chemistry and nuclear interactions in the time ...
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1answer
29 views

Charge density of sea water

If sea water contains salt ions and some H+ and OH- ions, what are the charge density of a certain volume of sea water? And is there a way to calculate?
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1answer
47 views

Why doesn't lithium form di-lithium crystals? (Calling Mr.Spock)

Hydrogen is in the first column of the periodic table. At STP it is a di-atomic gas. When cooled and/or under pressure it forms a crystalline solid of di-hydrogen molecules. Calculations indicate ...
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0answers
98 views

Why is Argon a noble gas?

Why is Argon a noble gas given that the 3d subshell is still empty? I understand that in Helium the n=1 level is full, so it is a noble gas. Now, Beryllium has a full 2s subshell but it is a metal. ...
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1answer
36 views

Constant pressure

When we refer to constant pressure like in Charles law what is this pressure? The pressure of the gas or the pressure that the container (the piston maybe) exert on the gas? Also does atmospheric ...
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2answers
59 views

What is the energy of an atomic orbital?

When we refer to energy of an atomic orbital what is this energy ? is potential energy ? but if is potential energy then shouldn't be considered the whole potential energy of the atom ( potential ...