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We can explain chemical anti-bonding just using the Pauli repulsion correct?Let's take He2.
2 atoms of He share 4 1s electrons and since the magnetic spin for electrons has 2 values there would be 2 electrons with the same wave function which would violate the Pauli exclusion principle.This makes He2 unstable and it... |
In *Concise Inorganic Chemistry* by J. D. Lee (adapted by Sudarsan Guha), in the chapter "Chemical Bonding", under the topic "Back Bonding with Nitrogen as a donor atom" the following reaction is given:
> $\ce{(SiH3)3N +4HCl \to NH4Cl + 3SiH3Cl}$ (bond cleavage through $\mathrm{S_N2}$ mechanism)
I have learnt abo... |
According to [this answer][1], heating potassium ferrocyanide will decompose it into potassium cyanide.
Now, potassium ferrocyanide is an approved anti-caking agent, and hence used in table salt, for example.
Table salt is often heated as part of cooking. So, isn't there a chance for trace quantities of potassium... |
Why is potassium ferrocyanide considered safe for consumption, when it is just one reaction away from the highly toxic potassium cyanide? |
In *Concise Inorganic Chemistry* by J. D. Lee (adapted by Sudarsan Guha), in the chapter "Chemical Bonding", under the topic "Back Bonding with Nitrogen as a donor atom" the following reaction is given:
> $\ce{(SiH3)3N +4HCl \to NH4Cl + 3SiH3Cl}$ (bond cleavage through $\mathrm{S_N2}$ mechanism)
I have learnt abo... |
How can methane absorb infrared light within wide range of frequency but CO2 can't? |
Is there a test to distinguish erythritol vs sugar at home, not with expensive lab equipment or exotic reagents? Sometimes I purchase erythritol online and wonder if it's been diluted with sugar. |
I am currently designing a synthesis requiring the use of hydroxy protecting groups. The problem I am having is that the protecting group must be able to survive highly acidic conditions. I would have loved to use a TMBS protecting group since it can withstand LAH, lewis acids, and strong base; however, not acidic cond... |
Is there a test to distinguish [erythritol](https://en.wikipedia.org/wiki/Erythritol) from sugar at home without expensive lab equipment or exotic reagents? Sometimes I purchase erythritol online and wonder if it's been diluted with sugar. |
>Is it less expensive?
Yes, but not so much that it would be favored, i.e. you don't worry about saving \$5 when your doing a \$5000 procedure.
>Is there a particular property of barium that makes it a better contrast?
No both absorb x-rays as a result of their high atomic numbers, in fact bismuth has more ele... |
Is this the right chemical formula of the complex: rubidium amminedibromidochloridoplantinat(II):
Rb[Pt(NH3)Br2Cl] ?
And is it correct that it has geometric isomerism, square planar with a cis and trans, leaving the rubdium out? |
What compressible rubber like gasket material is the least permeable to CO2? |
I think it should be -
**tetraamminechloridoiodoplatinum(IV) chloride iodide.**
The rules of the naming of counter ions are pretty much the same as in general Inorganic Chemistry. I do know of a compound AgClI - named as Silver chloride iodide. So, I think the counter ions here - chloride and iodide should be na... |
I am trying to obtain MAPbI3 as a bulk powder using lead (ii) iodide and methylammonium iodide as precursors.
I have not yet tried simply mixing the two in methanol/ethanol and removing the solvent in a rotavap, but this will simply result in a mixed salt with very little actual perovskite crystals if I am not mista... |
I am trying to obtain $\ce{CH3NH3PbI3}$ as a bulk powder using lead(II) iodide and methylammonium iodide as precursors.
I have not yet tried simply mixing the two in methanol/ethanol and removing the solvent in a rotavap, but this will simply result in a mixed salt with very little actual perovskite crystals if I am... |
I am trying to obtain $\ce{(MA)PbI3}$ as a bulk powder using lead(II) iodide and methylammonium iodide as precursors.
I have not yet tried simply mixing the two in methanol/ethanol and removing the solvent in a rotavap, but this will simply result in a mixed salt with very little actual perovskite crystals if I am n... |
Are there computational tools for identification of activity cliff between two analog compounds? This [paper][1] list chemotypes that with a high propensity to induce activity cliff.
[![enter image description here][2]][2]
[1]: https://link.springer.com/article/10.1007%2Fs11030-015-9609-z
[2]: https://i.... |
Is this the right chemical formula of the $\ce{Rb[Pt(NH3)Br2Cl]}$ complex: **rubidium amminedibromidochloridoplatinate(II)**?
And is it correct that it has geometric isomerism, being square planar with a *cis*- and *trans*-isomers, leaving the rubidium out? |
I have been reading through a [paper][1] about calculating the order of reaction for the following reaction:
[![enter image description here][2]][2]
The paper uses an iodine clock reaction with vitamin C to calculate its order of reactions, experimentally. However, when writing out the rate law, the author writes... |
I tried to find the place where you found the two statements, and I could not.
**Absence of long-range forces**
The first statement makes sense to me:
> There are no intermolecular forces except during the collision between molecules.
The [OpenStax Chemistry textbook][1], for example, has this statement:
... |
I have been reading through a [case study][1] about calculating the order of reaction for the following reaction:
$$\ce{H2O2 + 3 I- + 2 H+ -> I3- + 2 H2O}$$
The paper uses an iodine clock reaction with vitamin C to calculate its order of reactions, experimentally. However, when writing out the rate law, the autho... |
Often people say buy a cotton shirt because cotton "breathes" but polyester doesn't. (i.e. it makes you hot sweaty).
What is the scientific meaning behind this? How does polyester trap the heat more than cotton?
I would have thought it would be the other way round. Is there some chemical explanation? |
What does it mean "polyester doesn't breathe"? |
I've watched a [YouTube video "Soda Can Battery - Power From Trash - DIY Project" by Source Port Services](https://youtu.be/0F8cE4N42NQ). I understand that the anode can be oxidised, but what is the reduction reaction at the cathode? They are using a salt water solution $\ce{Na+}$ $\ce{Cl-}$ and a copper cathode.
$$... |
I was looking through a table of standard reduction potentials and the trend seemed like it correlated with electropositivity. Is it reasonable to qualitatively compare two metals to see which has a higher standard reduction potential based on electropositivity? If not, why is this unreasonable? |
My questions is that do secondary alcohols react faster than primary alcohols or is it the other around? This for the oxidation of the alcohol to a ketone or an aldehyde.
This reaction is with KMnO4 with a catalyst of H2SO4
Example of 2 alcohols:
butan-1-ol (primary)
propan-2-ol (secondary)
I thought that seco... |
Do secondary alcohols react faster than primary alcohols or is it the other around? |
Everyone knows the simplified photosynthesis-equation from school: 6CO2 + 6H2O -> C6H12O6 + 6O2. Most people assume that the carbondioxide is being split into carbon and oxygen during photosynthesis, and the equation seems to confirm this. BUT we know that is not true, and that the oxygen derived from photosynthesis ac... |
Everyone knows the simplified photosynthesis-equation from school:
$\ce{6CO2 + 6H2O -> C6H12O6 + 6O2}$
Most people assume that the carbondioxide is being split into carbon and oxygen during photosynthesis, and the equation seems to confirm this. But we know that is not true, and that the oxygen derived from phot... |
This is a summary of the account by Peter Brzezinski, Professor of Biochemistry, Stockholm University, Member of the Nobel Committee for Chemistry from the [Scientific Background][1] document.
> [Brzezinski:] Jacques Dubochet developed methods for preparation of samples for cryo-EM studies of biomolecules in water. ... |
Polystyrene plastic can be dissolved in acetone.
I would like to understand:
1. If the dissolved polystyrene will take-out of the acetone and becomes solid again (after all the acetone evaporates), will this solid polystyrene keep the same material properties as it was before the melting process?
2. How can I spee... |
If you labeled the oxygen atoms in carbon dioxide in green and the oxgyen atoms in dioxygen in red (because they derived from photosynthesis, while $\ce{CO2}$ is used up in the Calvin cycle), you would have to add some water molecules to be able to write an equation like this:
$$\ce{6C\color{limegreen}{\ce{O2}} + 12... |
What is the name of the radical that results from removing two hydrogen atoms from glyoxal (CHO-CHO)? It has a roughly this structure (O=C*-C*=O).
It is an important intermediate in heterogeneous electrocatalysis (for instance, [J. Phys. Chem. Lett. 2015, 6, 11, 2032-2037](https://doi.org/10.1021/acs.jpclett.5b007... |
What is the name of the radical that results from removing two hydrogen atoms from glyoxal ($\ce{CHO-CHO}$)? It has a roughly this structure: $$\ce{O=C^.-C^.=O}$$
It is an important intermediate in heterogeneous electrocatalysis (for instance, [J. Phys. Chem. Lett. 2015, 6, 11, 2032-2037](https://doi.org/10.1021/acs... |
What is the name of the glyoxal radical after removing two hydrogen atoms? |
Ionization isomerism is defined as complexes which have same empirical formula but ionize to different ions in solution.
Consider the complex $\ce{[Pt(NH3)4Cl2]I2}$. The other possible ionization isomers are:
$\ce{[Pt(NH3)4I2]Cl2}$ and $\ce{[Pt(NH3)4ICl]ICl}$.
But I have not come across the complexes similar to ... |
Is there any series of chemical reactions that will help in distinguishing propanone and butanone? A simpler series of reactions or tests would be optimal. |
Chemical Tests/Reactions to distinguish Propanone and Butanone? |
Is there any series of chemical reactions that will help in distinguishing propanone and butanone? A simpler series of reactions or tests would be optimal.
I know it's easy to distinguish and possibly separate by physical properties like boiling point but I need a chemical test or reaction.
So far I have thought up u... |
Polystyrene plastic can be dissolved in acetone.
I would like to understand:
1. If the dissolved polystyrene will take-out of the acetone and becomes solid again (after all the acetone evaporates), will this solid polystyrene keep the same material properties as it was before the dissolving process?
2. How can I s... |
Is there any series of chemical reactions that will help in distinguishing propanone and butanone? A simpler series of reactions or tests would be optimal.
I know it's easy to distinguish and possibly separate by physical properties like boiling point but I need a chemical test or reaction.
So far I have thought up... |
What are the chemical Tests and/or reactions to distinguish propanone from butanone? |
Phys.org's [How sulfur helped make Earth habitable before the rise of oxygen](https://phys.org/news/2019-11-sulfur-earth-habitable-oxygen.html) says
>Mapping the bonds and vibrational modes of molecules containing sulfur isotopes is helping to shed light on the chemical reactions that took place in Earth's atmospher... |
What is tetrasulfur like? Why is there so little experimental information about it? |
Phys.org's [How sulfur helped make Earth habitable before the rise of oxygen](https://phys.org/news/2019-11-sulfur-earth-habitable-oxygen.html) says
>Mapping the bonds and vibrational modes of molecules containing sulfur isotopes is helping to shed light on the chemical reactions that took place in Earth's atmospher... |
[This comment](https://chemistry.stackexchange.com/questions/34971/why-do-we-not-see-silicon-in-a-structure-like-graphite?rq=1#comment53641_34972) notes
>Graphene is not flat, either. Cannot be, because only 3D crystallites have perfect long-range order. Landau-Peierls instability this is called.
How general is t... |
Are all stable 2D Xenes and binaries buckled? |
According to the authors of [Ref. 1][1] this is a general property. They provide an explanation for the stability of such sheets based on formation of particular buckled geometries:
> The discovery of a flat two-dimensional crystal known as graphene has contradicted Landau−Peierls−Mermin−Wagner arguments that there... |
[This comment](https://chemistry.stackexchange.com/questions/34971/why-do-we-not-see-silicon-in-a-structure-like-graphite?rq=1#comment53641_34972) notes
>Graphene is not flat, either. Cannot be, because only 3D crystallites have perfect long-range order. Landau-Peierls instability this is called.
How general is t... |
Are all stable 2D Xenes and binaries buckled? |
In a recent paper by [Faber et . al.][1], Mean Absolute Error and DFT (B3LYP) error (relative to the experiments) for 9 properties of QM9 dataset molecules has been reported.
\begin{equation}
\begin{array}{l|ccccccccc}
{} & {\mu} & {\alpha} & {\varepsilon_{\text {HOMO }}}& {\varepsilon_{\text {LUMO }}} & {\Delta \v... |
I am carrying out a reaction using ethyl chloro acetate , potassium carbonate in acetone for a compound containing -NH group. so the substitution will be at -NH position.
i have tried stirring at room temperature, but no product obtained.
Refluxing has given a liquid product. reported product should be white crystals... |
I am carrying out a reaction using ethyl chloroacetate, potassium carbonate in acetone for a compound containing $\ce{-NH}$ group. So, the substitution will be at $\ce{-NH}$ position.
I have tried stirring at room temperature, but no product obtained.
Refluxing has given a liquid product. Reported product should be... |
If I combine two P orbitals in such a way that they form sigma bonds which linear combination will represent bonding and antibonding
My work on this problem:
Bonding: (Y1-Y2)
Antibonding: (Y1+Y2)
Where Y1 and Y2 are the wavefunctions of 1st and 2nd p orbitals.
Reason: While forming a bond , in bonding combination two l... |
Could you measure the pH of ocean water by using a strong acid-weak base titration? I was thinking that you could set up a standard titration with ocean water as the "unknown", and drip the known HCl solution into it until the equivalence point but I don't know you would go about figuring out the equivalence point and ... |
If I combine two p orbitals in such a way that they form sigma bonds which linear combination will represent bonding and antibonding
My work on this problem:
Bonding: (Y1-Y2)
Antibonding: (Y1+Y2)
Where Y1 and Y2 are the wavefunctions of 1st and 2nd p orbitals.
Reason: While forming a bond , in bonding combination two l... |
**background:** Per [this abstract](https://www.nature.com/articles/nmat4802)
>Silicene, germanene and stanene are part of a monoelemental class of two-dimensional (2D) crystals termed 2D-**Xenes** (X = Si, Ge, Sn and so on) which, together with their ligand-functionalized derivatives referred to as Xanes, are compr... |
Are all stable Xenes (graphene-like 2D honeycomb sheets) buckled? |
> If I combine two p orbitals in such a way that they form σ bonds, which linear combination will represent bonding and antibonding?
My work on this problem:
$$
\begin{align}
&\text{Bonding:} &(\phi_1 - \phi_2)\\
&\text{Antibonding:} &(\phi_1 + \phi_2)
\end{align}
$$
where $\phi_1$ and $\phi_2$ are the wa... |
Since global warming is expressed in terms of carbon emissions or CO2 equivalent, can the short lived carbon soot/ black carbon that is produced from incomplete combustion be expressed in terms of CO2 equivalent? I learnt Carbon soot is a major health risk. The purpose of doing this is to calculate how much of heating ... |
Is it possible to convert carbon soot/ black carbon in mg to CO2-equivalent? If so, how? |
Both PE and cotton produce CO2, but they distinctly have different smells while being burnt (Burning PE has smell of candle wax, while burning cotton’s smell is like burning leaves). Wool produces CO2 and N2 which is odorless, but yet has smell of hair burnt.
Moreover, they also differ in burning process (PE and w... |
Why polyethylene (PE), wool (polyamide) and cotton (cellulose) burnt with different smells, while they just product CO2 (and N2)? |
I'm planning an experiment that I'll do in silico in the near future, and one of the steps involve the extraction of the AlCl3-C2H5OH adduct without any water in it. My question is- can the ethanol be simply boiled off to obtain anhydrous aluminum chloride, or does it end up as, say, a mixture of ethyl chloride and alu... |
Is the reaction of anhydrous AlCl3 and anhydrous C2H5OH reversible? |
I'm planning an experiment that I'll do *in silico* in the near future, and one of the steps involves the extraction of the $\ce{AlCl3 · C2H5OH}$ adduct without any water in it.
Can the ethanol be simply boiled off to obtain anhydrous aluminum chloride, or does it end up as, say, a mixture of ethyl chloride and alu... |
Is the reaction of anhydrous aluminium(III) chloride and anhydrous ethanol reversible? |
There was this question I had to do on which went like "which all metals can we not extract using electrolysis from aq soln" the answer involved the effect of solvent on electrode potentials, can someone care to explain/ lead me to sources which will? |
How does solution which electrodes are immersed in effect electrode potential? |
Question: For each of the following pairs, choose the member with the lower boiling point. Explain your reason in each case.
HI (g) or HCl (g)
If they were both aqueous solutions, I would know that HCl has a lower boiling point. But the question specifically mentions gas. I believe that gas can't have a boiling p... |
Can a gas have a boiling point? |
What are your burning conditions?
PE fibers are indeed only carbon and hydrogen. But don't forget that wool is a protein (main component keratin) fiber and does not only contain carbon, oxygen and hydrogen, but also sulpher. That will also have an influence on your smell ;)
Whereas cotton is pure cellulose, if you d... |
Today, I had a friendly debate with my friend on what should be the oxidation state of $\ce {Cl}$ in the [chlorine monoxide][1] radical. I took the view that it should be $\ce {+2}$ while he took the view that it should be $\ce {+1}$. My reason for taking this view is simply that conventional state rules tell us that $... |
I am trying to figure out the structure of the compound $\ce{C3H5NO}$ given just the following data from the 1H NMR spectrum:
> $\delta 5.8 ~ \text{(singlet, 1H)}; \delta 6.2 ~ \text{(triplet, 2H)}; \delta 7.4~ \text{(triplet, 2H)}$
From 2-2-1 combination I have the following candidates:
[![enter image descr... |
> For each of the following pairs, choose the member with the lower boiling point. Explain your reason in each case.
> HI(g) or HCl(g)
If they were both aqueous solutions, I would know that HCl has a lower boiling point. But the question specifically mentions gas. I believe that gas can't have a boiling point.
... |
In a recent paper by [Faber et . al.][1], Mean Absolute Error and DFT (B3LYP) error (relative to the experiments) for 9 properties of QM9 dataset molecules has been reported.
\begin{equation}
\begin{array}{l|ccccccccc}
{} & {\mu} & {\alpha} & {\varepsilon_{\text {HOMO }}}& {\varepsilon_{\text {LUMO }}} & {\Delta \v... |
In a recent paper by [Faber et . al.][1], Mean Absolute Error and DFT (B3LYP) error (relative to the experiments) for 9 properties of QM9 dataset molecules has been reported.
\begin{equation}
\begin{array}{l|ccccccccc}
{} & {\mu} & {\alpha} & {\varepsilon_{\text {HOMO }}}& {\varepsilon_{\text {LUMO }}} & {\Delta \v... |
Suppose there is a solid made of avogadro number of, say, aluminium atoms. This solid is kept at 273 K. According to Maxwell-Boltzmann distribution, all the particles or atoms will not have the same thermal energy. Some atoms are cooler than 273 K, some are much warmer than that etc. But is this true?
I mean, accord... |
Suppose there is a solid made of avogadro number of, say, aluminium atoms. This solid is kept at 273 K. According to Maxwell-Boltzmann distribution, all the particles or atoms will not have the same thermal energy. Some atoms are cooler than 273 K, some are much warmer than that etc. But is this true?
I mean, accord... |
I'm attempting to calculate Mg ion vacancy migration inside Pyrope unit cell. System has total 159 atoms, beginning and end geometry is optimized. For intermediate image, I'm using one coordinate that I acquired from crashed NEB case. This is not perfect intermediate geometry, but I thought this should be enough one to... |
I know that the first shell can hold up 2, the second and third can hold up to 8, and the fourth 18. But what about after that? |
I know that the first shell can hold up to 2, the second can hold up to 6, and the third is 10. But what about after that? |
I'm having a bit of trouble with this question:
Which has a higher pH value, 0.001M HCl or 0.1M CH3COOH.
I have calculated that for the HCl solution (since it's a strong acid) the [H30+] = 0.001. Then, for the CH3COOH solution I got [H3O+] = 1.33*10^-3M (by solving a quadratic equation). Since the CH3COOH has a h... |
I'm having a bit of trouble with this question:
Which has a higher pH value, 0.001M HCl or 0.1M CH3COOH (given Ka = 1.8*10^-5).
I have calculated that for the HCl solution (since it's a strong acid) the [H30+] = 0.001. Then, for the CH3COOH solution I got [H3O+] = 1.33*10^-3M (by solving a quadratic equation). Si... |
Why 1,2 diiodo ethane is unstable? |
Consider this molecule: http://www.chemspider.com/Chemical-Structure.22823922.html
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/ODqEx.png
According to the chemspider nomenclature, this has three 'S' stereocenters. However, when I perform the CIP both manually and computationally, t... |
How do we know that there are different types of orbitals? For example, what evidence is there for the existence of $\mathrm{p}$ orbitals instead of there being multiple $\mathrm{s}$ orbitals (for example, why isn't the electronic configuration of sodium $\mathrm{1s^1, 2s^2, 2s^2, 2s^2, 2s^2, 3s^2...}$)? |
I'm having a bit of trouble with this question:
> Which has a higher $\mathrm{pH}$ value, $\pu{0.001 M}$ $\ce{HCl}$ or $\pu{0.1 M}$ $\ce{CH3COOH}$ $(K_\mathrm{a} = \pu{1.8E-5})?$
I have calculated that for the $\ce{HCl}$ solution (since it's a strong acid) the $[\ce{H3O+}] = \pu{0.001 M}.$
Then, for the $\ce{C... |
Diiodoethane is a product of the reaction between glycol and $\ce{PI3}$. Why is 1,2-diiodoethane unstable? |
Why is 1,2-diiodoethane unstable? |
Consider [(1*S*,2*S*,4*S*)-bicyclo[2.2.1]hept-5-en-2-yl]acetic acid:
[![[(1S,2S,4S)-bicyclo[2.2.1]hept-5-en-2-yl]acetic acid][1]][1]
(Source: http://www.chemspider.com/Chemical-Structure.22823922.html)
According to the chemspider nomenclature, this has three *S* stereocenters. However, when I perform the ... |
No. Maxwell-Boltzman statistics are not followed. The Equipartition Theorem is followed (at equilibrium) but the distribution tends to be more like a Planck Distribution giving different equations for $v_{avg}$. Consider that solids arguably don't have an atomic $v_{avg}$ (or rather it is zero) and that liquids differ ... |
What is a material more easily cut than shattered? |
The crystalline property that would allow to cut the "diamond creature" (or whatever those things are in your universe) you are looking at is [cleavage](https://en.wikipedia.org/wiki/Cleavage_(crystal)) (a writer might also use a term in a wordplay).
In crystallography, cleavage is the ability of crystals to crack or ... |
To solve the problem, think about what is the condition for a radial node- what happens to the density $|\Psi_{\textrm{3s}}^2|$ at a node? First some definitions: $r$ is the distance from the nucleus and $a_0$ is a constant distance called the Bohr radius (=0.5291 Å).
>! The density, given by $$|\Psi_{\textrm{3s}}^... |
Options:
1. Acidified K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>
2. KMnO<sub>4</sub>
3. Chromyl Chloride
4. H<sub>2</sub>O<sub>2</sub>
On searching on google, I got the answer as Option 1 - Acidified Potassium Dichromate but my question is-
- How is the test administered? How much time does it take for... |
Which chemical is used in Drunken Driver Test? |
Options:
1. Acidified K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>
2. KMnO<sub>4</sub>
3. Chromyl Chloride
4. H<sub>2</sub>O<sub>2</sub>
On searching on google, I got the answer as Option 1 - Acidified Potassium Dichromate but my question is-
- How is the test administered? How much time does it take for... |
Options:
1. Acidified K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>
2. KMnO<sub>4</sub>
3. Chromyl Chloride
4. H<sub>2</sub>O<sub>2</sub>
On searching on google, I got the answer as Option 1 - Acidified Potassium Dichromate but my question is-
- How is the test administered? How much time does it take for... |
What would you suggest to hold the vacuum set-point? Thank you. |
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