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Question from the online class:
> Can two s-orbitals can overlap as shown?
>
> [![overlapping s-orbitals][1]][1]
>
> Dotted circles in diagram depict maximum probability region of s-orbitals in ideal situation when atoms A and B are not bonded. Black dots denote nuclei.
Answer by teacher: no because extent o... |
Question from the online class:
> Can two s-orbitals overlap as shown?
>
> [![overlapping s-orbitals][1]][1]
>
> Dotted circles in diagram depict maximum probability region of s-orbitals in ideal situation when atoms A and B are not bonded. Black dots denote nuclei.
Answer by teacher: no because extent of ov... |
How to make 4-cyclohexene-1,2-diol from cyclohexa-1,4-diene? |
Paulings electronegativity is a relative scale, based on the difference in electronegativity between X and Y, $\Delta EN = 0.102 \sqrt {\Delta}$, where $\Delta = (X-Y)_{measured}-(X-Y)_{theoretical}$ bond energies.
But what is the oxidation state of X and Y? Is it an average of the common oxidation states for each ... |
Which oxidation states were used when Pauling developed his electronegativity scale? |
For my Master's Thesis I am working with the dicarboxylic acid muconic acid (H2MA) (pKa1 = 2.9, pKa2 = 4.0). It thus dissociates into HMA- and MA2- respectively. I am aware of how to calculate the pH and the subsequent dissociation percentage when dissolving a weak acid in water. But I am wondering how you can calculat... |
What is the dissociation percentage of a polybasic organic acid at a certain pH? |
For my Master's Thesis I am working with the dicarboxylic acid muconic acid ($\ce{H2MA}$) ($\mathrm{pK_{a1} = 2.9, pK_{a2} = 4.0}$). It thus dissociates into $\ce{HMA-}$ and $\ce{MA^2-}$ respectively. I am aware of how to calculate the pH and the subsequent dissociation percentage when dissolving a weak acid in water. ... |
For my Master's Thesis I am working with the dicarboxylic acid muconic acid $(\ce{H2MA},$ $\mathrm{p}K_\mathrm{a1} = 2.9,$ $\mathrm{p}K_\mathrm{a2} = 4.0).$ It thus dissociates into $\ce{HMA-}$ and $\ce{MA^2-},$ respectively.
I am aware of how to calculate the $\mathrm{pH}$ and the subsequent dissociation percentage... |
I know that the relation between 1 amu and Avogadro number is a reciprocal relation. My question is if the definition of 1 amu is changed, suppose instead of 1/12th mass of C-12 isotope, we consider 1/24th mass of C-12 isotope, will the Avogadro number change? And if Avogadro number changes will that change the mass of... |
Will Avogadro number change if definition of 1 amu is changed? |
In a recent installment of [Deus Ex game series][1] there is an augmentation called ["Titan Shield"][2] (it has nothing to do with $\ce{Ti}$ element):
> A neodymium skin underlay matrix built of nano-meshed rare earth magnets and powered with hook-ins to the Biocell electrical system, the TITAN skin augmentation can... |
I know that the maximum number of electrons within a shell is equal to 2n^2. I would think that the noble gases would reflect this but that isn’t always the case
n = 1
2(1^2) = 2, this is the atomic number of He ✅
n = 2
2(2^2) = 8, plus the 2 e from n = 1, this is 10, which is the atomic number for Ne ✅
n = 3
2*(3... |
I know that the maximum number of electrons within a shell is equal to 2n^2. I would think that the noble gases would reflect this but that isn’t always the case
n = 1
2(1^2) = 2, this is the atomic number of He ✅
n = 2
2(2^2) = 8, plus the 2 e from n = 1, this is 10, which is the atomic number for Ne ✅
n = 3
2*(3... |
How to make cyclohex-4-ene-1,2-diol from cyclohexa-1,4-diene? |
I am conducting a school-based research project into the antioxidative properties of green tea. Part of the procedure is to determine the concentration of antioxidant in green tea. This antioxidant is [EGCG][1] (a type of *catechin*).
One of the problems I am facing is that most of the procedures I find on the inter... |
I have spent the last couple of days learning to navigate, find useful information and use the download service on the PubChem website. One of the pieces of information you can find is a stereocenter count, but I can't seem to find anything about the stereocenter location. <br />
This might just be something that isn'... |
>I am conducting a school-based research project into the antioxidative properties of green tea. Part of the procedure is to determine the concentration of antioxidant in green tea. This antioxidant is EGCG (a type of *catechin*).
First of all, you cannot determine the concentration of just EGCG (epigallocatechin ga... |
I know that the relation between atomic mass unit and Avogadro's number is a reciprocal relation.
My question is if the definition of atomic mass unit is changed, suppose instead of 1/12th mass of carbon-12 isotope, we consider 1/24th mass of carbon-12 isotope, will the Avogadro's number change?
And if Avogadro's... |
Will Avogadro's number change if definition of atomic mass unit is changed? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/ey2u0.png
I am looking for any help in developing a mechanism for this transformation as well as determining the stereochemistry on the starred centers. I do not see any obvious connections. I was thinking that the second to last step woul... |
The number of orbitals per shell (n) is n<sup>2</sup>. At most there are two electrons per orbital, each with opposite spin. However, due to nuclear screening, the subshells (n and l), and as a result the orbitals (n, l, and m<sub>l</sub>) are not of the same energy.
When you get to more complicated situations, suc... |
Both N are sp<sup>3</sup> hybridized. Both N are quaternary nitrogens with a positive formal charge. The tBu group is more electron donating (think vectors of the N-C-C geometries) than the iPr group, but there is more of a steric penalty due to its bulk; on the other hand, the N-C-H linkage in the iPr ammonium cation ... |
Mechanistically, the N-H is deprotonated to form an amide ion. In basic medium, the hydroxyl group may be slightly deprotonated as well, but the pKa are not drastically different and this is not mechanistically useful. You can envision an isocyanate forming upon rearrangement, which is then subject to nucleophilic atta... |
HF paint stripper on data sheets lists
Methylene chloride 70>85%
Methanol 10>25%
Hydrofluric acid. 5%
Previously I have found the chemical splits. Is there a particular method to properly blend all 3 parts?
|
How can I mix methylene chloride, methanol and hydrofluric acid to make a paint stripper? |
>I am conducting a school-based research project into the antioxidative properties of green tea. Part of the procedure is to determine the concentration of antioxidant in green tea. This antioxidant is EGCG (a type of *catechin*).
First of all, you cannot determine the concentration of just EGCG (epigallocatechin ga... |
It says in Wikipedia that lead tetrahydride or hydrogen *plumbide* or plumbane (PbH4) is supposed to have lead in it's -4 state and the hydrogen is in its +1 state because supposedly lead has a higher electronegativity than hydrogen . Is this possible to be synthesized and actually be stable for long enough to at least... |
What is the desired stereochemical outcome of the product?
1. For cis-diol, use 1/2 eq KMnO4/NaOH
2. For trans-diol, use 1/2 eq MCPBA followed by catalytic H2SO4/H2O (excess H2SO4 will cause protonation of the π bond and lead to undesired polymerization and other unwanted side products)
Does this help? :) |
While testing for anions using dil H2SO4, we prefer using the soda extract for tests rather than the actual salt. But we don’t use it for tests of carbonates, bicarbonates and sulphites. Why is this so?
I get that soda extract itself is a carbonate so no point to use it for carbonates but why not bicarbonates and sulp... |
So, my question is how would I make a bridge as seen on the following molecule (Right side)?
[![Left side is Molecule A, right side is Molecule B][1]][1]
[1]: https://i.stack.imgur.com/roP3t.png
As for the molecule in the Left, I am supposed to make it using that molecule as a base. The only requirement is... |
I have read that ROH+ NaOH doesn't form alkoxide ions because water is a stronger acid than all alcohols except methanol. However while reading xanthate test I found that alcohol reacts with KOH to form alkoxide ions. Why is it so?
|
why doesn't alcohol react with sodium hydroxide but react with potassium hydroxide? |
>I am conducting a school-based research project into the antioxidative properties of green tea. Part of the procedure is to determine the concentration of antioxidant in green tea. This antioxidant is EGCG (a type of *catechin*).
First of all, you cannot determine the concentration of just EGCG (epigallocatechin ga... |
We had an experiment on the dissolution of calcium hydroxide and we obtained the experimental entropy value -203 J/mol-k with a percent error of 26.7%. Doesn't dissolving a solid in a solvent increase entropy? |
Why does the dissolution of calcium hydroxide has a negative entropy? |
If I consider a ketone that has an ethyl group and a methyl group attached to it. The α-Hydrogen of the methyl group would be more acidic than that of the ethyl group due to -I effect of the adjacent carbon in ethyl group. However the double bond formed in the enol form would be more stable in case it is formed using t... |
We had an experiment on the dissolution of calcium hydroxide and we obtained the experimental entropy value $\pu{-203 J mol^-1 K^-1}$ with a percent error of $26.7\%.$ Doesn't dissolving a solid in a solvent increase entropy? |
I have seen one company call as you have seen below:
> Call for "Development of Zircon Alternative Formulations in Ceramic Tile Glazing Industry"
So I have searched for finding the low-cost alternative for zirconia crowns by these terms:
- [diy ceramic crown](https://www.google.com/search?q=diy+ceramic+c... |
Can anyone also explain me the mechanism of this reaction?
[![enter image description here][1]][1]
I think it might be formation of acetal or hemiacteal reaction but I am not sure about it.
[1]: https://i.stack.imgur.com/38A9U.png
[2]: https://i.stack.imgur.com/i4BQu.png |
I understood how to find aromatic nature of single aromatic rings (like benzene) or that of combination of rings which are independently aromatic, such that the electrons of one ring do not enter into another ring (like biphenyl).
However I don't have much clarity on finding the aromatic nature if electrons from 2 o... |
While testing for anions using dilute $\ce{H2SO4}$, we prefer using the soda extract for tests rather than the actual salt. But we don’t use it for tests of carbonates, bicarbonates and sulphites. Why is this so?
I get that soda extract itself is a carbonate so no point to use it for carbonates but why not bicarbona... |
Conceptual problem:
>Let $A + 2B \rightarrow C + 2D$ be a reaction under constant pressure ($P$) and temperature ($T$), that goes all the way towards the products. $\ce{A,B,C,D}$ are ideal gases. Let $\Delta H$ be the molar enthalpy change in the reaction.
>
>What is the change in the internal energy?
The tota... |
I was met with a question that required me to find which complex is an outer orbital complex, and two of the options included $\ce{ [Ni(NH3)6]^2+}$ and $\ce{[Co(NH3)6]^3+}$,
I want to know why does $\ce {NH3}$ acts as a strong field ligand and cause pairing of electrons in d orbital in the case of $\ce{[Co(NH3)6]^... |
Why does NH3 cause pairing in case of some metal complexes and doesn't in case of others? |
>The relative molecular masses of A, B, and C were found to be $101.30$, $87.30$ and $144.90$ respectively, compared to an assigned value of exactly $2.00$ for $\ce{H2}$. Subsequently, these substances were subjected to elemental analysis and were found to contain $37.2\%$, $64.8\%$ and $78.0\%$ of $\ce{X}$ respectivel... |
I understood how to find aromatic nature of single aromatic rings (like benzene) or that of combination of rings which are independently aromatic, such that the electrons of one ring do not enter into another ring (like biphenyl).
However I don't have much clarity on finding the aromatic nature if electrons from 2 o... |
The following instructions are given for a preparation and I am wondering what it means to "shear an emulsion"?
> The water phase components and the oil phase components are each mixed
> in separate containers and filtered and the refractive index of each
> is measured. The refractive index of the water phase is a... |
Why does the dissolution of calcium hydroxide have a negative entropy? |
So, my question is how would I make a bridge as seen on the following molecule (right side)?
[![Left side is Molecule A, right side is Molecule B][1]][1]
[1]: https://i.stack.imgur.com/roP3t.png
As for the molecule on the left, I am supposed to make it using that molecule as a base. The only requirement is... |
What is the composition of diet coke? |
It says in [Wikipedia][1] that lead tetrahydride or hydrogen *plumbide* or plumbane ($\ce{PbH4}$) is supposed to have lead in its -4 state and the hydrogen is in its +1 state because supposedly lead has a higher electronegativity than hydrogen. Is this possible to be synthesized and actually be stable for long enough t... |
Referring to, *NCERT Chemistry Part I, Textbook for Class XI*<sup>[1]</sup>.
[![ClF3][2]][2]
Here the text puts forward three structures of $\ce{ClF3}$.
My teacher said to me that (b) structure is unstable due to lone pair lone pair repulsion while (a) is the most stable of the given structures as there are mi... |
In my book(*NCERT Chemistry Part I, Textbook for Class XI*<sup>[1]</sup>) a list of values of electron gain enthalpies of various elements is given. According to that list, oxygen has less negative electron gain enthalpy than selenium, tellurium and polonium. Shouldn't it be the opposite because electron gain enthalpy ... |
I have the following observations:
* When I put a solution of glucose (80 g/ℓ) and ammonium chloride (20 g/ℓ) in a drying cabinet at 37°C (maybe a bit warmer) a brown substance forms when all (or most) of the water has evaporated.
* When I add water to the reaction product, the substance dissolves within minutes... |
Referring to, *NCERT Chemistry Part I, Textbook for Class XI*<sup>[1]</sup>.
[![ClF3][2]][2]
Here the text puts forward three structures of $\ce{ClF3}$.
My teacher said to me that (b) structure is unstable due to lone pair lone pair repulsion while (a) is the most stable of the given structures as there are mi... |
What reaction happens between glucose and ammonium chloride when drying? |
Draw the reaction mechanism between a Benzene ring with SiMe3 group and I-Cl?
Draw the mechanism of Diphenyldichlorosilane and excess Mg?
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/tQRVE.png |
Can someone explain these reactions? It's in relation to a siloxane polymer experiment |
Draw the reaction mechanism between a Benzene ring with SiMe3 group and I-Cl?
Draw the mechanism of Diphenyldichlorosilane and excess Mg?
I believe the first reaction would be a substitution of SiMe3 for I and creating SiMe3Cl.
The second process I think would involve the Mg removing the two Cl and forming diphen... |
I understood how to find aromatic nature of single aromatic rings (like benzene) or that of combination of rings which are independently aromatic, such that the electrons of one ring do not enter into another ring (like biphenyl).
However I don't have much clarity on finding the aromatic nature if electrons from 2 o... |
Since you are asking for a theoretical explanation, I believe a theoretical calculation might be helpful. It is possible to calculate the partial charges on atoms using electronic structure programs. I have calculated the partial charges at $\text{B3LYP/pcseg-1//GFN2-xTB}$ level (with GAMESS and xTB).
### $\ce{Me-\o... |
Since you are asking for a theoretical explanation, I believe a theoretical calculation might be helpful. It is possible to calculate the partial charges on atoms using electronic structure programs. I have calculated the partial charges at $\text{B3LYP/pcseg-1//GFN2-xTB}$ level (with GAMESS and xTB).
### $\ce{Me-\o... |
Since you are asking for a theoretical explanation, I believe a theoretical calculation might be helpful. It is possible to calculate the partial charges on atoms using electronic structure programs. I have calculated the partial charges at $\text{B3LYP/pcseg-1//GFN2-xTB}$ level (with GAMESS and xTB).
### $\ce{Me-\o... |
I need help with a basic concentration problem.
If I have a $\mathrm{2~M}$ solution, and want to make a $\mathrm{0.1~M}$ solution of $\mathrm{100~ml}$, how would I go about that?
My work:
$$M_1V_1 = M_2V_2$$
Where $M_1 = \text{initial concentration}$, $M_2 = \text{final concentration}$, $V_1 = \text{volum... |
Since you are asking for a theoretical explanation, I believe a theoretical calculation might be helpful. It is possible to calculate the partial charges on atoms using electronic structure programs. I have calculated the partial charges at $\text{B3LYP/pcseg-1//GFN2-xTB}$ level (with GAMESS and xTB).
### $\ce{Me-\o... |
I need help with a basic concentration problem.
If I have a $\mathrm{2~M}$ solution, and want to make a $\mathrm{0.1~M}$ solution of $\mathrm{100~ml}$, how would I go about that?
My work:
$$M_1V_1 = M_2V_2$$
Where $M_1 = \text{initial concentration}$, $M_2 = \text{final concentration}$, $V_1 = \text{volum... |
[![Silane reaction][1]][1]
I believe the first reaction would be a substitution of $\ce{SiMe3}$ for $\ce{I}$ and creating $\ce{SiMe3Cl}$.
The second process I think would involve the $\ce{Mg}$ removing the two $\ce{Cl}$ and forming diphenylsilane, which would likely be a repeating unit in a silicone polymer.
... |
Equivalent concept is an archaic unit of measurement that was used in chemistry and the biological sciences in the era before researchers knew how to determine the chemical formula for a compound.
An [equivalent][1] (symbol: officially equiv; unofficially but often Eq) is the amount of a substance that reacts with ... |
A)SiMe3 Increases the inductivity and reduces Aromaticity,
so by free radical (uv termination?) its likely to have p-iodideSi(Me)3Bencene.
[![enter image description here][1]][1]
B)Dimer crystal solution in Cl- ions. (Ph)2Si(Cl)Mg+---ClSi(Ph)2
Or Solid crystals of (Ph)2Si(Cl)MgCl.
[![enter image descript... |
I have this exercise from my H.W:
[![enter image description here][1]][1]
and I am asked: if we split the solution into 3 different containers equally -
- how many moles will the solution have in each container?
- will the Cl- concentration change?
for the first question, I answered 0.08/3 moles. my com... |
will splitting a solution will keep the concentration values (and moles) the same? |
Tellurium-128 is the longest lived radioisotope with a half life decay length of 2.3 septillion (2.3x10^24) years.I know I've heard something about so called "magic numbers" that if you have the perfect amount of protons and neutrons in a nucleus but why is this though,is it a coincidence ,or just pure luck that tellur... |
Why is tellurium-128 so "stable"? |
Tellurium-128 is the longest lived radioisotope with a half-life decay length of 2.3 septillion (2.3x10^24) years.I know I've heard something about so called "magic numbers" that if you have the perfect amount of protons and neutrons in a nucleus it usually is radioactive but has an absurdly long half-life. But why is ... |
The respective configutations of a and b are...?
[![enter image description here][1]][1]
I tried to find the answer for a (for me is: 2S, 3S) but I'm not sure of my results, can someone help me?
[![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/C5UNj.png
[2]: https://i.stack.im... |
R or S configuration? |
Tellurium-128 is the longest lived radioisotope with a half-life decay length of 2.3 septillion ($2.3*10^{24}$) years. I know I've heard something about so called "magic numbers" that if you have the perfect amount of protons and neutrons in a nucleus it usually is radioactive but has an absurdly long half-life. But wh... |
I was reading an article and found the following reaction sequence:
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/Pv2Nl.png
The second step involves a formylation of the hydrazone with the Vilsmeier reagent to, first synthesize the pyrazole ring and then, to formylate it to produce t... |
I am working on a project where one of the goals is to store data from computational quantum chemistry calculations for later retrieval. Currently, we are trying to store the outcomes of simple bond (or angle or dihedral angle) "scan jobs". The main problem we have is in finding a way to represent the scan coordinate t... |
*Entropy* can be measured and aproached differently, (i) from an equation that relates entropy and *Enthalpy* to measure the heat of reaction, the remainder of the work done per degree of *Temperature* (°) is [![enter image description here][1]][1]
or if the enthalpy is measured then simply. [![enter image descrip... |
*Entropy* can be measured and aproached differently, (i) from an equation that relates entropy and *Enthalpy* to measure the heat of reaction, the remainder of the work done per degree of *Temperature* (°) is [![enter image description here][1]][1]
or if the enthalpy is measured then simply. [![enter image descrip... |
*Entropy* can be measured and aproached differently, (i) from an equation that relates entropy and *Enthalpy* to measure the heat of reaction, the remainder of the work done per degree of *Temperature* (°) is [![enter image description here][1]][1]
or if the change in enthalpy is measured then simply. [![enter ima... |
Tellurium-128 is the longest lived radioisotope so far with a half-life of 2.3 septillion ($2.3*10^{24}$) years. I know I've heard something about so called "magic numbers" that if you have the perfect amount of protons and neutrons in a nucleus it usually is radioactive but has an absurdly long half-life (Examples bis... |
Why is tellurium-128 so stable compared to the other radioisotopes? |
I need help with a basic concentration problem.
If I have a $\mathrm{2~M}$ solution, and want to make a $\mathrm{0.1~M}$ solution of $\mathrm{100~ml}$, how would I go about that?
My work:
$$M_1V_1 = M_2V_2$$
Where $M_1 = \text{initial concentration}$, $M_2 = \text{final concentration}$, $V_1 = \text{volum... |
I need help with a basic concentration problem.
If I have a $\mathrm{2~M}$ solution, and want to make a $\mathrm{0.1~M}$ solution of $\mathrm{100~ml}$, how would I go about that?
My work:
$$M_1V_1 = M_2V_2$$
Where $M_1 = \text{initial concentration}$, $M_2 = \text{final concentration}$, $V_1 = \text{volum... |
Tellurium-128 is the longest lived radioisotope so far with a half-life of 2.3 septillion ($2.3*10^{24}$) years. I know I've heard something about so called "magic numbers" that if you have the perfect amount of protons and neutrons in an atomic nucleus it usually is radioactive but has an absurdly long half-life (exam... |
Recently I came across a question asking which compounds are Anti aromatic. This was one of the options:
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/S7q2i.jpg
I’m confused as this is **NOT** an answer. I think the lone pair electrons on the carbanion participate in resonance and s... |
Trying to prove that nitrogen doesn't split its lone pair to form 5 bonds, I thought of a situation that I couldn't rule out; the paired electron being excited to the 3s orbital, so that five bonds could be formed- in an "$\ce{sp3s}$" hybridisation.
I know hybridisation is just an observation-based explanation, but ... |
Why doesn't an sp3s hybridisation exist? |
Recently I came across a question asking which compounds are anti-aromatic. This was one of the options:
>[![enter image description here][1]][1]
I’m confused as this is not an answer. I think the lone pair electrons on the carbanion participate in resonance and so there are 8π electrons which, follows the 4nπ... |
Why is the tropylium anion non-aromatic? |
The counter question that might help you rule this out is: "Which 3s orbital?" Note that atomic Nitrogen doesn't have a 3s orbital.
[![enter image description here][1]][1]
Also note that in hybridization, *Atomic orbitals of **same or almost similar energies** intermix to form same number of new Hybrid orbital... |
The counter question that might help you rule this out is: "Which 3s orbital?" Note that atomic Nitrogen doesn't have a 3s orbital as N itself belongs to the 2nd period(n=2).
[![enter image description here][1]][1]
Also note that in hybridization, *Atomic orbitals of **same or almost similar energies** intermi... |
Suppose that I wanted to electroplate Al(s) onto a Cu(s) Cathode, (using an Aluminium Nitrate solution and Al(s) anode).
At standard conditions, Al(s) is the strongest reducing agent, which is good. However, H2O (l) is a stronger oxidising agent than Al3+, which should mean that no Al3+ can be reduced to form the coat... |
How is it possible to electroplate using an Al3+ solution, when water is a stronger oxidant? |
I have 100% acetic acid (glacial) with a pH of 2.4 and I want to know how much DM water is required to dilute the acetic acid and obtain a solution with a pH of 4.3.
As per observation 0.0001 M is equal to pH 4.3. So how can I implement this calculation using the Nernst equation? |
How much water is required to dilute glacial acetic acid to given pH? |
> In which of the following chemical compounds are the building blocks molecules?
>
> (A) $\ce{AgNO3}$
> (B) $\ce{HNO3}$
> (C) $\ce{KNO3}$
> (D) $\ce{NaNO3}$
(B) is the correct answer, but I have no idea why. Could you briefly explain why this is the correct answer?
|
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