Questions tagged [chemical-compounds]
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112 questions
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Bi-Quartz Polarimeter
I have confusion regarding bi-quartz polarimeter, that when we try to measure specific rotation of a compound with respect to another compound (like water), when do we have to stop for taking readings?...
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Considering enthalpy of formation and sensible enthalpy in steady-flow systems
I am reading a book (Thermodynamics an Engineering approach), I am reading over the section of steady-flow systems with chemical reactions.
The book just introduced the following formula for the ...
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How does mass-energy equivalence work with chemical bonds? [duplicate]
If you have, for instance, 2 oxygen atoms and do E=mc2 to get their equivalent energy, you get about 2.38nJ. However, if you have diatomic oxygen, there's also the energy of the bond; about 0.8aJ. ...
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Flatband with our Moire Physics
Is there any material Class available where the lattice vectors are in the order of several nm instead of Angstrom? I am looking for some exotic not well studies lattice class which can be ...
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Spectroscopy on colored flames
When observing colored fire through a spectrometer after adding substances like copper chloride or magnesium sulfate to change its color, what specific spectra are typically observed? How does the ...
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Why are things electronegative and electropostive?
Chemical reactions happen because of electron donation. Atoms already have an equal amount of proteins and electrons, so they should cancel out and the atom should not have to steal/donate electrons. ...
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Nature of absorption spectra peaks similar profile in Dimethyl sulfide (C$_2$H$_6$S)
I was reading interesting article about possible life signs detection in exoplanets, where JWS telescope have captured that exoplanet K2-18 b atmosphere has Dimethyl sulfide traces. This chemical ...
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Understanding enthalpy and gibbs energy changes in a reaction
I was looking at the enthalpy change for water-splitting reaction:
$$ \Delta H^o_R = [\Delta H^0_{H_2(g)} +\frac{1}{2}\Delta H^0_{O_2(g)}]-\Delta H^0_{H_2O(l)} = 285.83 kJ/mol$$
According to the ...
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What is the difficulty of determing the products of nuclear fission?
In my impression, initially many people did not believe that an Uranium nucleus disintegrates into two halves when bombared with neutrons.
Experimentally, there must be some difficulty to determine ...
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Why can a material mixture block all light?
Dyes and different colorings are often mixed into materials. These are usually a small fraction of the total material volume/mass and aren't painted on so don't have a uniform surface coat but some ...
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Gibbs energy calculations for compounds
I am studying machine learning during my master's degree and have a simple task. I am using the FactSage Pure Substance Database (https://www.crct.polymtl.ca), which provides a list of phases for a ...
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How much $\rm D_2O$ is in Earth's icepacks? [closed]
How much $\rm D_2O$, by mass and/or percentage, is locked in Earth's polar icepacks? Is the $\rm D_2O$:$\rm H_2O$ ratio the same as elsewhere?
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Difference between Reversible and Irreversible processes in Physics vs. Chemistry
In Physics a reversible process is defined as one in which the system can be returned to its initial conditions via the same path (along the PV Diagram), and every point along the path is an ...
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Strange occurrence of glue drying
What happened here? I by accident spilled super glue and formed these amazing ridge patterns. Any ideas what caused this to happen?
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Can we call rusting of iron a combustion reaction?
In case of rusting of iron the chemical reaction is not fast enough. The oxygen used is not molecular oxygen from the atmosphere but it is the oxygen from water molecule. The reaction is not rapid and ...
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Do diamagnets, such as graphite, have a Curie point?
Since graphite can be heated by induction, can it also lose its magnetism at a certain temperature just like ferromagnetic metals? And what about materials such as graphene(that is also from carbon) ...
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Why does the air pressure not increase when I shake a coke bottle?
I tried this experiment lately and this happened, I shook a coke bottle and its air pressure remained the same but the coke came squirting out when I opened the lid. How is this possible?
user333186
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Calculating Enthalpy of formation versus Calculating Enthalpy of a reaction not occurring at standard conditions
My understanding of Hess's law and its use in determining the change of enthalpy of a reaction has been challenged recently.
Up until recently, I thought that the only way to calculate a chemical ...
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Why isn't the molecule of water linear straight?
When you see models of water you see something like this:
The hydrogens in the water molecule become negatively charged because the oxygen pulls electrons more. So why don't they repel and move to ...
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Degrees of Freedom contributing to dynamic?
I had a question regarding considering how many degrees of freedom (dof), contributing to dynamics, a $\rm CCl_4$ Molecule has.
In General there are 5 Atoms in the Molecule, so the maximum would be 15,...
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Role of methane in global warming
I am a young student in physic and I am doing a little presentation on how does climate change works. So I went on the wikipedia page for greenhouse gases.
I don't understant why methane is more ...
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Meaning of notation: $\mathrm{Sm}\left(\mathrm{Fe}_{0.8} \mathrm{Co}_{0.2}\right)_{12}$
I am reading a research paper about magnetic materials based on $\mathrm{SmFe_{12}}$ compounds (https://doi.org/10.1016/j.actamat.2020.05.026). They talk about the material $\mathrm{Sm}\left(\mathrm{...
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Why aren't common magnets made of magnetite, $\rm Fe_3O_4$? Instead of ferrite, $\rm Fe_2O_3$?
Why are common, simple, cheap magnets like refrigerator magnets made (usually) of hematite ($\rm Fe_2O_3$) in some form, like 'ferrite', instead of the more magnetic and magnetizable magnetite ($\rm ...
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Why is Earth's atmosphere made almost entirely of $\rm N_2$ and $\rm O_2$ molecules rather than any of the nitrogen oxides?
I assume the formation of $\rm N_2$ and $\rm O_2$ molecules is energetically favorable compared with N2O, NO, and NO2, etc., but are there some more intuitive arguments regarding the bonding and ...
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What would be preferred site for $\rm N$ and $\rm B$ co-doping in the ethylcyclohexane?
I want to replace two carbon of ethylcyclohexane: one $\rm C$ with $\rm B$ and the adjacent $\rm C$ with $\rm N$ in my hydrocarbon. Could you please explain me with possible reason that where can I ...
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Does potassium hydroxide etch steel?
Potassium hydroxide is a good etching agent for glasses. If the sample is laser processed, then the etching rate is much more faster.
I want to use stainless steel (because of its good thermal ...
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Simulating breaking bonds in molecular dynamics
How does one introduce the possibility of breaking a bond in a molecule during MD simulation?
I only found the cases when we just introduce the harmonic potential $U_{ij} = \frac{1}{2}k(r_i - r_j)^2$ ...
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How does ski wax (nonpolar liquid) dissolve into polyethylene (nonpolar plastic)?
Ive been reading alot about ski waxing and a reputable source said that when you iron in paraffin wax into the base of a ski or snowboard, the wax melts from the heat of the iron and dissolves into ...
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Benzene ground state
I’m currently studying my first course on Quantum Physics. Regarding the topic of Sommerfeld’s quantization rules, I’ve come across a problem where I was asked whether a benzene molecule would require ...
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Microscopic interpretation of constant voltage from Battery
I don't know if this is the right place to ask(Maybe it's more related to chemistry), but this has been troubling me for some while.
Consider you have a chemical cell. Then the reason for the ...
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What does the subindex $x$ in $\text{Bi}_{1-x}\text{Sb}_{x}$ mean?
I am currently reworking our condensed matter lecture. We shortly discussed topologic insulaters at the example of
$$\text{Bi}_{1-x}\text{Sb}_{x}$$
I am not sure what the $x$ stands for. Normally ...
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Why is 99% isopropyl alcohol preferred for a DIY cloud chamber?
Simple cloud chamber construction is described in various places and all seem to use 90% - 99% isopropyl alcohol as a start. What property does this have that makes it an essential component for ...
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How to simulate the formation of chemical bonds by calculating electrodynamic forces?
I had the idea recently that if the interactions between atoms could be calculated, that a large enough computer could simulate biological processes.
What would I need to know to simulate something ...
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Covalent bonding in cuprates
In high temperature cuprate superconductors like YBCO, there are intermediate copper-oxide planes, where $Cu$ and $O$ atoms are arranged alternatively in a square lattice. In this arrangement, the $Cu$...
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Increase the surface tension of polypropylene
I'm working on a project and I need to increase the surface energy of polypropylene. I want you to tell me a way in order to increase surface energy of polypropylene?
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Increasing the melting point of metal
I need to know how one can increase the melting point of a metals like steel, tungsten or ... about 500 degrees and without destroying its shape?
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In chemical compounds, where does the "magic" come from in atomic "magic numbers"?
It is well known that atoms with a full electron shell are more stable, it is one of the first facts taught in a middle school Chemistry course:
"An element whose atoms have no electrons
outside ...
user137661
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What is the temperature at which Napalm burns?
I was sitting during a lecture last week in one of my classes, and we were talking about chemical warfare and the history behind it.
My teacher had brought up the use of Napalm during Vietnam. After a ...
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Why is gaseous carbon dioxide transparent? [closed]
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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How is aerogel made? [closed]
Aerogel is a promising material capable of a high thermal insulation. What is the production process of aerogel, is it a cheap technology?
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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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Do CFCs get emitted in air from appliances?
Do the refrigerators and air conditioners that use CFC or HCFC cause damage to the environment even when they are working normally. I mean, is there any gas emission under normal conditions when the ...
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Carrying 10 liter dewar in elevator advisable? [closed]
I am using liquid nitrogen a lot at university and frequently have to carry a 10 l dewar from the storage container into my lab. On this way I have to walk down 4 stories with the heavy dewar. ...
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How to quantify the mixing of two hard-spheres gases?
Suppose that there are two types of hard-spheres gases ($a$ and $b$) in a box. Suppose that their radius is much smaller than the box's characteristic size. These two gases tend to repel each other. ...
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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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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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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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What do the planets in our solar system smell like? [closed]
For example, if Jupiter is mostly hydrogen and and helium, but has ammonia clouds, does that mean it smells like a cat's litterbox?
Does Mars smell like iron?
Asking in order to give kids a more "...
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Is there any non-metallic oxide that remains in solid state at room temperature?
Except for metallic and semimetallic oxides, is there any oxide (non-metallic oxide) which remains in the solid state at room temperature?
