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I have some small cured epoxy shafts I am cutting segments out of for checking Tg by DSC. First scan gave a Tg of 118 °C, follow on was 109 °C. Scans were repeated on a new sample of the shaft with similar results.
250 °F curing dicy based epoxy system. Neat resin before cure has exotherm onset at 127 °C and the cu... |
In each of these cases, the ether will generally be cleaved to produce 2 alkyl halides. Acidic clevage can occur via Sn2 or Sn1 depending on the nature of the substrate. A bulky group, such as tert-butyl, will undergo an Sn1 mechanism in which the protonated ether group leaves before the nucleophile attacks. The same p... |
> **Question**
> An electron in a hydrogen like atom makes a transition from a state in which its de-Broglie wavelength is $\lambda_1$ to a state in which its de-Broglie wavelength is $\lambda_2$, then wavelength of photon generated due to this transition will be ___________.
The solution for this problem as give... |
Why potential energy is neglected in this problem for calculating the energy difference between two stationary Bohr Orbits? |
> **Question**
> In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inner-orbit jumps of the electron for Bohr orbits in an atom of hydrogen?
> (A) $3\to2$
> (B) $5\to2$
> (C) $4\to1$
> (D) $2\to5$
>Only one option is correct.
**M... |
> If in the hydrogen atom Potential Energy at $\infty$ is chosen to be $13.6$eV then the ratio of Total energy and Kinetic Energy(with the sign) for $1$st Bohr Orbit is?
**My Attempt**<br>
I just simply gave the answer given the relation that,
$$\text{T.E}:\text{K.E}:\text{P.E} = -1:1:-2$$
Because I think we d... |
This is my first post, so please bear with me.
At work I have some chlorbutyl plungers that I need to clean (pref. according to GMP) from any residual material that might be left after production.
Any advice?
Br,
David |
>what happens if a ether with a 2° alkyl group and a 1° alkyl group is cleaved with a halogen acid?
To this question I have drawn a scheme below. The given ether is $\ce{2^0}$ group to the left and methyl to right. Acid cleavage with a halogenic acid involves an initial protonation of ether. In an $\ce{S_N^2}$ react... |
This is my first post, so please bear with me.
**At work I have some chlorbutyl plungers that I need to clean from any residual material that might be left after production.**
A colleague of mine told me that he has seen a GMP description of how to clean chlorbutyl plungers, but was unable to find it. GMP stand ... |
I am trying to self learn solomon's organic chemistry book, but there is no explanation over why we should use THF in oxymercuration. After a quick search I found out that THF help stabilize in hydroboration, but is it the same for oxymercuration? and I still don't understand why and how THF can help stabilize in hydro... |
This is my first post, so please bear with me.
At work I have some chlorobutyl plungers that I need to clean from any residual material that might be left after production.
A colleague of mine told me that he has seen a GMP (Good Manufacturing Practice) description of how to clean chlorobutyl plungers, but was un... |
In by book, under the topic Heterogeneous Equilibrium it is given
> For pure solid and pure liquid, active mass is taken to be unity, i.e., 1 as they remain constant throughout the reaction.
I read some related answers to similar question but none addresses which compounds are pure which are not.
Could you pl... |
What is meant by pure solids or pure liquids? |
In by book, under the topic Heterogeneous Equilibrium it is given
> For pure solid and pure liquid, active mass is taken to be unity, i.e., 1 as they remain constant throughout the reaction.
Could you please explain what are the pure solids and liquids being mentioned here?
I read some related answers to simil... |
If, say, propenal undergoes nucleophilic addition of hydrazine, will the 1,2- adduct or the 1,4-adduct be preferred? Why?
There is an obvious reasonace structure with an electrophilic beta carbon so under proper conditions will the 1,4-adduct dominate? |
Is the 1,4-adduct of carbonyl compounds ever a major product over the 1,2-adduct? |
I am working on a project wherein I am studying various properties of human hair and its utilization..I would like to know method by which we can extract melanin from human hair. Can anyone suggest some cost effective method? |
> [![Reaction between 1,7‐dichloroheptan‐4‐one and alcoholic KOH][1]][1]
The given answer is 1,1-dicyclopropylmethanone:
[![1,1-dicyclopropylmethanone][2]][2]
Step 1 is abstraction of acidic H by the strong base. Then, there's surely going to be anchimeric assistance. But there can be two places where the firs... |
Why the formation of PH4+ is difficult compared to NH4+? |
Upon mixing both acids, the reaction between Formic Acid and Sulfuric Acid, besides producing Carbon Monoxide and Water, releases a certain amount of acid fumes.
Does anyone know if the fumes, in that specific reaction, are of only one of the acids or both of them?
Also, is there a good way to predict release of ... |
Is it possible to predict release of acid fumes in certain acid reactions? |
You can conveniently normalize the peak height to unity, if your sole purpose is to compare the peak shapes. It is not forbidden at all. However you should not attempt any quantitation.
You can read the paper here
[Total peak shape analysis: detection and quantitation of concurrent fronting, tailing, and their eff... |
Not only do "outer" electrons impart some shielding to "inner" ones, but an analytical technique is based on that fact.
In [X-ray photoelectron spectroscopy](https://en.wikipedia.org/wiki/X-ray_photoelectron_spectroscopy), binding energies of electrons just below the outer shell are measured. These binding energies... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/P7C3t.png
I understand that in E there is no electrophile the amine can attack, however, I do not understand why A is an answer as well. The amine in A can perform an intramolecular attack on the aldehyde and form the product below. Why ca... |
Which of these reactants will not generate this racemic amine? |
When I did CAN test on ethyl acetate red colour was seen. I thought water may get added with Ethyl acetate to produce
[this compound][1] which in turn gave red coloration but carbon should not make three bonds with oxygens easily.
What could be the possible explanation to this phenomena?
[1]: https://drive.google.co... |
**a.** Reaction of $\ce{CO2}$ addition in water is as follows:
$\ce{CO2}$ + $\ce{H2O}$ $\ce{->}$ $\ce{H2CO3}$
**b.** Then, pH of $\ce{H2CO3}$ solution is increased to 12 by addition of 1M $\ce{NaOH}$.
So, the reaction would be:
$\ce{2NaOH(aq)}$ + $\ce{H2CO3(aq)}$ $\ce{->}$ $\ce{Na2CO3(aq)}$ + $\ce{2H2O}$
... |
Why is activation energy drawn in a potential energy diagram in reactions? |
I'm an amateur analog photographer and want to react Nitric Acid (62%) and silver to Silver nitrate. Silver nitrate is the basis for almost all black and white photography.
I'm trying to figure out the correct ratio of silver to nitric acid. The reaction is 3Ag(s)+4HNO3(aq) -> 3AgNO3(l)+NO(g)+2H2O (l)
Can I calc... |
I'm an amateur analog photographer and want to react Nitric Acid (62%) and silver to Silver nitrate. Silver nitrate is the basis for almost all black and white photography.
I'm trying to figure out the correct ratio of silver to nitric acid. The reaction is $$\ce{3Ag(s) +4HNO3(aq) -> 3AgNO3(l) +NO(g) +2H2O (l)}$$
... |
I would like to use a liquid solvent for some experimentation with a carbon dioxide solubility as low as possible under usual pressure and temperature conditions (say, $\pu{1 atm}$ and $\pu{293 K}$).
Until then, I was unable to find much information on the topic:
- A study of $\ce{CO2}$ solubility in water and se... |
Eq. (9.12.23) in [1] states that:
$$\sum_{abcd}c_{ab}c_{cd}g_{abcd}>0\tag{MEST 9.12.23}\label{91223}$$
Now for $c=a$ and $d=b$ giving:
$$c_{ab}c_{ab}>0$$
Which seem obvious as long as $c$ are real numbers.
It can thus be seen that to fulfill Eq. (\ref{91223}) that:
$$g_{abab}>0 \tag{MEST 9.12.24}$$
W... |
12.5g of commercial sodium bicarbonate gives 3 g of carbon dioxide. What is the percentage in purity in the sample?
$$2NaHCO_3 \rightarrow Na_2CO_3+CO_2+H_2O$$
I have solved this question, but I just need my solution verified, as it’s not given. I have solved it as follows
Molar mass of sodium bicarbonate=84
M... |
Cobalt atomic no. 27 has electronic configuration [Ar] 4s2 3d7.
I have seen two different configurations and explanations for Co 3+ from a variety of different sources.
1) Either it loses to 4s electrons and becomes [Ar] 3d6 in accordance with aufbau's principle
2) Or it loses one 4s electron and two 3d electr... |
Electronic configuration of Co 3+? |
12.5g of commercial sodium bicarbonate gives 3 g of carbon dioxide. What is the percentage in purity in the sample?
$$\ce{2NaHCO_3 -> Na_2CO_3 + CO_2 + H_2O}$$
I have solved this question, but I just need my solution verified, as it’s not given. I have solved it as follows
Molar mass of sodium bicarbonate=84
M... |
I guess the reason is hydrogen bonding but shouldn't both the trends be similar in that case? |
Why NH3 has higher melting point than HF while the boiling point is lower than HF? |
Eq. (9.12.23) in [1] states that:
$$\sum_{abcd}c_{ab}c_{cd}g_{abcd}>0\tag{MEST 9.12.23}\label{91223}$$
with $c_{ab}=c_ac_b$ for $c_a$ being molecular orbital coefficients and $g_{abcd}$ being the two-electron integrals in AO basis. Now for $c=a$ and $d=b$ giving:
$$c_{ab}c_{ab}>0$$
Which seem obvious as lon... |
Eq. (9.12.23) in [1] states that:
$$\sum_{abcd}c_{ab}c_{cd}g_{abcd}>0\tag{MEST 9.12.23}\label{91223}$$
with $c_{ab}=c_ac_b$ for $c_a$ being some distribution coefficients and $g_{abcd}$ being the two-electron integrals in AO basis. Now for $c=a$ and $d=b$ giving:
$$c_{ab}c_{ab}>0$$
Which seem obvious as lon... |
The order given in my book is
NH3>SbH3>AsH3>PH3
Phosphorous is more electronegative than As and Sb then shouldn't the dipole moment be more in case of PH3 .
And why does the anomaly of NH3 occur? |
Why does the dipole moment order of group 15 hydrides increase down the group? |
I guess the reason is hydrogen bonding, but shouldn't both the trends be similar in that case? |
Why does ammonia have higher melting point but lower boiling point than HF? |
To find the ground state density in DFT, you set the following Lagrangian:
$$L = E[\rho(\vec r)] - \mu\left(\int \rho d\vec r - N\right)$$
While minimising with respect to the density, we get:
$$\frac{\partial L}{\partial \rho} = \frac{\partial E[\rho(\vec r)]}{\partial \rho} - \mu = 0$$
My problem is with ... |
I'm quite curious about this:
In a basis set (I'll just use minimal-basis STO-nG basis sets for convenience), the basis functions are written as a linear combination of primitive GTOs. Are the GTOs normalised first, like this:
$$\Psi^\mathrm{STO} = \sum_i N_i c_i \phi_i^\mathrm{GTO}$$
where $\phi_i^\mathrm{GTO... |
Are primitive GTOs normalised before contraction, or is the resultant basis function normalised afterwards? |
Cobalt (atomic number 27) has electronic configuration $[\ce{Ar}]\mathrm{(4s)^2 (3d)^7}.$
I have seen two different configurations and explanations for $\ce{Co^3+}$ from a variety of different sources:
1. either it loses two $\mathrm{4s}$ electrons and becomes $[\ce{Ar}]\mathrm{(3d)^6}$ in accordance with aufbau ... |
> In $\ce{H2C=CH-Br}$ and $\ce{H3C-CH2-Br}$, which will react faster towards a $\mathrm{S_N2}$ reaction?
According to me, as double bond exhibit −*I* effect, hence the 1st should do a faster reaction. Am I right, or is there any other reason? |
**a.** Reaction of $\ce{CO2}$ addition in water is as follows:
$\ce{CO2}$ + $\ce{H2O}$ $\ce{->}$ $\ce{H2CO3}$
**b.** Then, pH of $\ce{H2CO3}$ solution is increased to 12 by addition of 1M $\ce{NaOH}$.
So, the reaction would be:
$\ce{2NaOH(aq)}$ + $\ce{H2CO3(aq)}$ $\ce{->}$ $\ce{Na2CO3(aq)}$ + $\ce{2H2O}$
... |
I was recently studying about Metallurgy.
*Concise Inorganic Chemistry* by J. D. Lee claims the process of froth floatation can also be applied to non-sulfide ores such as Malachite ($\ce{CuCO3.Cu(OH)2}$) and Anglesite ($\ce{PbSO4}$) by using $\ce{Na2S}$ as an activator.
The coatings formed are $\ce{CuS}$ and ... |
If I react selenium powder with copper chloride powder above the melting point of selenium (221 C), will I end up with a chunk of copper selenide, with the chlorine given off as gas, or will I lose some or all of the Se as as Selenium Chloride gas? |
The $C_{18}$ allotrope cyclocarbon [has been synthesized and imaged](https://science.sciencemag.org/content/early/2019/08/14/science.aay1914). *Science* has most details behind a paywall, but [this](https://www.sciencenews.org/article/chemists-have-created-and-imaged-new-form-carbon) discussion includes an image:
[!... |
Why does this image of cyclocarbon look like a nonagon? |
If I react selenium powder with copper chloride powder above the melting point of selenium (221 °C), will I end up with a chunk of copper selenide, with the chlorine given off as gas, or will I lose some or all of the Se as as selenium chloride gas? |
A hydrogen anion has a bigger radius than neutral H . Why is this happening ? I mean both electrons exist at the same shell so this is not it . Both H- and H have 1 proton so this is not it as well . Both electrons of the hydrogen ion have the same energy level and they dont shield the charge of the core from one anoth... |
I have learnt that in order for dissolution to occur, the solute-solvent intermolecular forces must be strong enough to overcome the solute-solute and solvent-solvent forces. However if this is the case, why are non-polar substances such as methane able to partially dissolve in polar solvents such as water? Aren't the ... |
There are many ways to synthesize copper selenide. It is generally has two forms $\ce{Cu2Se}$ and $\ce{CuSe}$ but is actually non-stoichiometric. They are grown as nanoparticles for various applications like making semiconductor, optoelectronic components, sensors etc.
1. By direct combination of copper and seleni... |
(Ca,Co)CO3
I have never EVER seen this before. What does this mean exactly? |
What does a comma signify in inorganic chemistry? |
I have been trying to read how to fix plastic problems, there seems to be 3 outstanding solutions
1. Re-use
2. Recycle
3. Decompose to Fuel
Recycling is expensive, requires lots of water and the quality degrades on each recycle. I can partially understand why companies won't recycle
However I am unable t... |
Wikipedia article on ortho effect suggests that o-toulic acid is more acidic than benzoic acid. This fact is rationalized by suggesting that steric effect causes COOH group to "twist" out of the plane and which increases it's acidity as it inhibits "cross-conjugation"that it was previously taking part in.
My instru... |
How does cross-conjugation destabilizes a molecule? |
There are many ways to synthesize copper selenide. It generally has two forms $\ce{Cu2Se}$ and $\ce{CuSe}$ but actually it is a non-stoichiometric compound. They are grown as nanoparticles for various applications like making semiconductor, optoelectronic components, sensors etc.
1. By direct combination of copper... |
![The two conformers:]
(https://i.stack.imgur.com/ad90h.jpg)
Out of these two, which one is more stable? I'm unable to imagine the orientation of the the lone pairs of O, and ABMO of Course and Cl bond.
Any tips to tackle these kind of problems? |
To find the ground state density in DFT, you set the following Lagrangian:
$$L = E[\rho(\vec r)] - \mu\left(\int \rho(\vec r) \mathrm{d}\vec r - N\right)$$
While minimising with respect to the density, we get:
$$\frac{\partial L}{\partial \rho} = \frac{\partial E[\rho(\vec r)]}{\partial \rho} - \mu = 0$$
My... |
![The two conformers:]
(https://i.stack.imgur.com/ad90h.jpg)
Out of these two, which one is more stable? I'm unable to imagine the orientation of the lone pairs of O and ABMO of C and Cl bond.
Any tips to tackle these kind of problems? |
[![2‐chlorooxane conformers][1]][1]
Out of these two, which one is more stable? I'm unable to imagine the orientation of the lone pairs of O and ABMO of C and Cl bond.
Any tips to tackle these kind of problems?
[1]: https://i.stack.imgur.com/zuGa9.png |
$\ce{(Ca,Co)CO3}$
I have never *ever* seen this before. What does this mean exactly? |
I was looking at the code required for a simple RHF computation when I came across the section for the diagonalisation of the Fock Matrix.
Based on what I know, the diagonal matrix $\mathbf{s}$ is evaluated as
$$\mathbf{s} = \mathbf{U}^\dagger\mathbf{S}\mathbf{U},$$
where $\mathbf{S}$ is the overlap matrix.
... |
How do I calculate the number of stereoisomers? Since each carbon is linked to 4 different groups, can I claim that all are chiral and therefore, 2^8 stereoisomers are possible?
If that is true, since there is no elem... |
You are missing an important part in the quote (the first sentence):
>Fixing the point of inversion at the origin implies that one of the symmetry operators is -x,-y,-z. What are the symmetry operators for the glide plane and screw axis? (The answer is clearly listed, but suppose it was not given here!) The symmetry... |
> The molecule given below is a substituted cubane.
> [![(1R,3R,5S,7S)‐1‐bromo‐3‐chloro‐5‐iodocubane][1]][1]
> a) How many stereoisomers exist for this molecule?
> b) How many pairs of enantiomers are possible?
How do I calculate the number of stereoisomers? Since each carbon is linked to four different gro... |
Wikipedia article on ortho effect suggests that o-toulic acid is more acidic than benzoic acid. This fact is rationalized by suggesting that steric effect causes COOH group to "twist" out of the plane and which increases it's acidity as it inhibits "cross-conjugation"that it was previously taking part in.
My instru... |
Wikipedia article on ortho effect suggests that o-toulic acid is more acidic than benzoic acid. This fact is rationalized by suggesting that steric effect causes COOH group to "twist" out of the plane and which increases it's acidity as it inhibits "cross-conjugation"that it was previously taking part in.
My instru... |
We have to get the temperature of the isotherm for water for which the local minimum is at 100 Pa. Use the values of a and b of water.
My approach:
In the van der waal equation, set dP/dV = 0 and get the value of T. Plug this value in the initial van der waal equation and and solve for V from the biquadratic.
T... |
We have to get the temperature of the isotherm for water for which the local minimum is at $100 \text{ Pa }$. Use the values of $a$ and $b$ of water.
My approach:
In the van der waal equation, set $\frac{dP}{dV} = 0$ and get the value of $T$. Plug this value in the initial van der waal equation and and solve for ... |
We have to get the temperature of the isotherm for water for which the local minimum is at $100 \text{ Pa }$. Use the values of $a$ and $b$ of water.
My approach:
In the Van der Waals equation, set $\frac{dP}{dV} = 0$ and get the value of $T$. Plug this value in the initial Van der Waals equation and and solve fo... |
> Get the temperature of the isotherm for water for which the local minimum is at $\pu{100 Pa}.$ Use the values of $a$ and $b$ of water.
### My approach
In the van der Waals equation, set
$$\frac{\mathrm dP}{\mathrm dV} = 0$$
and get the value of $T.$ Plug this value in the initial van der Waals equation a... |
$\ce{(Ca{,}Co)CO3}$
I have never *ever* seen this before. What does this mean exactly? |
A hydrogen anion has a bigger radius than neutral H . Why is this happening ? I mean both electrons exist at the same shell so this is not it. Both H- and H have 1 proton so this is not it as well . Both electrons of the hydrogen ion have the same energy level and they don't shield the charge of the core from one anoth... |
> The molecule given below is a substituted cubane.
> [![(1R,3R,5S,7S)‐1‐bromo‐3‐chloro‐5‐iodocubane][1]][1]
> a) How many stereoisomers exist for this molecule?
> b) How many pairs of enantiomers are possible?
How do I calculate the number of stereoisomers? Since each carbon is linked to four different gro... |
> The molecule given below is a substituted cubane.
> [![(1R,3R,5S,7S)‐1‐bromo‐3‐chloro‐5‐iodocubane][1]][1]
> a) How many stereoisomers exist for this molecule?
> b) How many pairs of enantiomers are possible?
How do I calculate the number of stereoisomers? Since each carbon is linked to four different gro... |
> Get the temperature of the isotherm for water for which the local minimum is at $\pu{100 Pa}.$ Use the values of $a$ and $b$ of water.
### My approach
In the van der Waals equation, set
$$\frac{\mathrm dP}{\mathrm dV} = 0$$
and get the value of $T.$ Plug this value in the initial van der Waals equation a... |
I'm learning about rate law and equilibrium, and the textbook really hammers in that the exponents for the rate law must be determined experimentally - you can't just use the coefficients from the balanced equation. In a generic reaction aA + bB -> cC + dD:
r<sub>f</sub> = k<sub>f</sub>[A]<sup>w</sup>[B]<sup>x</sup>... |
Why are the equilibrium exponents stoichiometric when the rate law's are not? |
I'm learning about rate law and equilibrium, and the textbook really hammers in that the exponents for the rate law must be determined experimentally - you can't just use the coefficients from the balanced equation. In a generic reaction aA + bB -> cC + dD:
r<sub>f</sub> = k<sub>f</sub>[A]<sup>w</sup>[B]<sup>x</sup>... |
There are many ways to synthesize copper selenide. It generally has two forms $\ce{Cu2Se}$ and $\ce{CuSe}$ but actually it is a non-stoichiometric compound. They are grown as nanoparticles for various applications like making semiconductor, optoelectronic components, sensors etc.
1. By direct combination of copper... |
I have a mixture of Et2O, EtOH and water, and I want to distill off the ether. I am using a water bath so not much water is distilled over, as the boiling water is 100C, and the solvent has like 20C lower temp than the water bath working temp, I believe. So, my point is, is it safe and reasonable to make a bath with 95... |
Can you heat something ot alcohol bath? |
If akyl groups are ordered alphabetically and ethyl comes before methyl, would this compound be called 2-ethyl-3,4 dimethyl pentane? Since that would be less than 4-ethyl-2,3 dimethyl pentane, correct?
|
How would you order alkyl groups of this compound numerically? |
Can you heat something at alcohol bath? |
which is more basic an oxaziridine or diaziridine? |
Is it safe to boil water in a foil pan on an electric burner?
Can the metal leach into the water?
I've heard some reports recently about avoiding aluminum foil due to it leaching into food.
Photos of the items in question, below:
[![Foil pan][1]][1]
[![Electric burner][2]][2]
[1]: https://i.stack.... |
Is it safe to boil water in a foil pan on an electric burner? |
I have a mixture of $\ce{Et2O},$ $\ce{EtOH}$ and water, and I want to distill off the ether. I am using a water bath so not much water is distilled over, as the boiling water is 100 °C, and the solvent has like 20 °C lower temp than the water bath working temp, I believe.
So, my point is, is it safe and reasonable t... |
For an application I need a commercial, transparent liquid with refractive index n>2, is there this kind of liquid available?
On the web only n=1.81 is routine. The second question is, what's the chemical composition of this?
|
Is there a commercial liquid with refractive index greater than n=2? |
In my book, under the topic of redox reactions, it is given,
> In all redox reactions, the total increase in oxidation number must be equal to the total decrease in oxidation number.
Is this a consequence of "Charges can never be created. The total charge of a system remains constant", or something else?
For t... |
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