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In cathode ray tube experiment in order to check the direction of flow of electrons a hole was made in a note and behind it phosphorescent material Zinc sulphide it was coated.
**Why do Zinc Sulphide glow when hit by electrons?**
What caused this glow ?
|
Why do Zinc Sulphide glow when hit by electrons? |
In cathode ray tube experiment in order to check the direction of flow of electrons a hole was made in a note and behind it phosphorescent material zinc sulfide it was coated.
Why does zinc sulfide glow when hit by electrons?
What causes this glow?
|
Why does zinc sulfide glow when hit by electrons? |
When a C of a molecule is not a chiral centre, the spatial orientation of its substituent group doesn't affect its stereochemical specification, does it?
Ex: [![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/ejfi4.png |
I've read [here on stack-exchange][1] that NaOH will react with glass through the following reaction:
4 NaOH + SiO2 ⤑ Na4SiO4 + 2 H2O
I would like to briefly heat a highly concentrated NaOH solution to 140-200C over the course of a few minutes just to pass it through a filter.
Beside safety concerns, several q... |
Highly concentrated NaOH solution at high temperature vs borosilicate glassware and cellulose? |
Why does the tautomerism of purine favors 9H-purine? |
Ca(HCO3)2 has the following solubility values:
16.1 g/100 mL (0 °C)
16.6 g/100 mL (20 °C)
18.4 g/100 mL (100 °C)
So I assume Ca(HCO3)2 would precipitate beyond this level. However, [the wikipedia page for calcium bicarbonate][1] states that attempts to prepare compounds such as solid calcium bi... |
They have slightly different pKa values of 9.9 (phenol) vs 10.2 (p-methoxyphenol).
They both have the same number of resonance structures too.
My guess is that the resonance structure for p-methoxyphenol with the lone pair on the para carbon contributes less to the stabilisation of the negative charge since it's i... |
Why is p-methoxyphenol less acidic than phenol? |
They have slightly different $\mathrm{p}K_\mathrm{a}$ values of 9.9 (phenol) vs 10.2 (*p*-methoxyphenol).
They both have the same number of resonance structures too.
My guess is that the resonance structure for *p*-methoxyphenol with the lone pair on the *para* carbon contributes less to the stabilisation of the n... |
Why does the tautomerism of purine favor 9H-purine? |
I am reading about A cathode ray discharge tube and I still do not fully understand why that as you keep on lowering the pressure in the chamber it creates striations, Faraday's dark space and Crooke's dark space and why it does not just stay as a constant stream of light? Also why does the gas have to be at a low pres... |
Will this compound show Geometrical isomerism? |
Application of the Michaelis-Menten equation generally assumes steady state concentration of the enzymatic complex intermediate. Then $K_M$ allows two interpretations$^1$:
* an apparent dissociation constant describing the equilibrium $$\ce{ES<=>E +S}\tag{1}$$
where $E$ and $S$ are the concentrations of enzyme an... |
I was looking through Basis Set Exchange when I noticed quite a few basis sets (STO-3G to STO-6G, for example) have negative contraction coefficients for some primitive Gaussians. As (based on what I know) the overlap between two STO-nG basis functions is equal to the sum of the overlap integrals between the pGTOs used... |
Basis sets - negative contraction coefficients? |
The most important question is why do we need low pressures? If you recall kinetic theory of gases, there is a concept of mean free path. This quantity roughly tells us the distance a particle would travel before colliding with another particle. If you want the electrons to travel from one end to the other, you need to... |
The most important question is why do we need low pressures? If you recall kinetic theory of gases, there is a concept of mean free path. This quantity roughly tells us the distance a particle would travel before colliding with another particle. If you want the electrons to travel from one end to the other, you need to... |
With the Fisher Fusion Orbitrap mass spectrometer I can do both CID and HCD collision induced dissociation studies.
When I apply CID on inorganic molecules I observe more fragmentation products than with just CID suggesting multiple fragmentation steps. However I don't get why physically this is possible.
Is HCD d... |
Difference between HCD and CID collision induced dissociations? |
Will N,N‐diethylbenzamide show geometrical isomerism? |
Is colour always associated with paramagnetism? |
Why is sodium peroxide not of white colour even if it is paramagnetic? |
I have been researching the production of peroxy acids and other strong oxidizers. I was wondering if it's possible to produce permanganic acid if I were to cast an anode with molten elemental sulfur and Manganese Dioxide from a battery?
I was
|
With the Thermo-Fisher Fusion Orbitrap mass spectrometer I can do both CID (collision-induced dissociation) and HCD (higher energy C trap dissociation) collision-induced dissociation studies.
When I apply CID on inorganic molecules I observe more fragmentation products than with just CID suggesting multiple fragmen... |
Calcium bentonite can be electroplated onto steel. After it is electroplated on to steel it has a rough and porous like surface that is very hard and tough.
If you were to electroplate a thin layer of calcium bentonite onto steel then brush on a thin coating of copper oxide. The copper oxide would stick to the surf... |
Electroplating boat hulls with ceramic like material containing copper oxide to prevent barnacles from sticking? |
### Brief overview of CID vs. HCD
"Collision-induced dissociation" or CID is a much older and more general term in mass spectrometry than HCD. HCD is a vendor-specific term invented to describe a new modification on how ions can be dissociated in Orbitrap mass spectrometers. CID is a "universal" term that applies ... |
I have to compare the acidic strength of these compounds:
[![A: 2‐hydroxybenzoic acid; B: 2,6‐dihydroxybenzoic acid; C: 2‐methylbenzoic acid][1]][1]
Now, in **A** and **B** hydrogen bonding will be present which will help stabilize the negative charge of the conjugate base. However, the hydroxyl group is not bulk... |
I am designing an experiment that involves immersing pieces of pipe lining in a mixture of *tert*-butyl mercaptan (2 %) and white mineral oil (98 %) at 230 °C (the standard temperature for the test). If I was using pure *tert*-butyl mercaptan I would be concerned with it exploding, due to its auto ignition temperature ... |
First off, to not overlook the obvious, both reactions ares thermodynamically favored.
$$\ce{MgO (s) + H2O (l) -> Mg(OH)2 (aq)} \\
\Delta G_\pu{298K}^\circ = \pu{-833.7 kJ mol-1 -( -569.3 kJ mol-1 + -306.7 kJ mol-1) = - 42.3 kJ mol-1}$$
$$\ce{CaO (s) + H2O (l) -> Ca(OH)2 (aq)} \\
\Delta G_\pu{298K}^\circ =... |
With the Thermo-Fisher Fusion Orbitrap mass spectrometer I can do both CID (collision-induced dissociation) and HCD (higher energy C trap dissociation) collision-induced dissociation studies.
When I apply HCD on inorganic molecules I observe more fragmentation products than with just CID suggesting multiple fragmen... |
### Brief overview of CID vs. HCD
"Collision-induced dissociation" or CID is a much older and more general term in mass spectrometry than HCD. HCD is a vendor-specific term invented to describe a new modification on how ions can be dissociated in Orbitrap mass spectrometers. CID is a "universal" term that applies ... |
According to [wikipedia][1] Ca(HCO3)2 has the following solubility values:
16.1 g/100 mL (0 °C)
16.6 g/100 mL (20 °C)
18.4 g/100 mL (100 °C)
So I assume Ca(HCO3)2 would precipitate beyond this level. However, [the wikipedia page for calcium bicarbonate][1] states that attempts to prepare compound... |
I know the general idea behind x-ray crystallography is to take a high quality crystal and place it in the path of an x-ray beam. Areas of high electron density will diffract the beam and lead to spots on a detector screen where photons have constructively interfered with each other (and nothing appears where destructi... |
How were x-ray diffraction patterns decifered before computers? |
I agree with @andselisk that this question is quite broad. I will focus on two specific questions asked
>The only equation I know for x-ray diffraction is Bragg's Law but is this the only equation used to interpret the data? [...] How do you translate the spots on a detector to electron density plots using Braggs la... |
I agree with @andselisk that this question is quite broad. I will focus on two specific questions asked
>The only equation I know for x-ray diffraction is Bragg's Law but is this the only equation used to interpret the data? [...] How do you translate the spots on a detector to electron density plots using Braggs la... |
[This question][1] regarding appropriate handling of hot concentrated aqueous NaOH - with particular concern for [avoiding dissolution of borosilicate glassware][2] and contamination of the NaOH solution and other reagents - led me to think of two possible solutions:
1. Coat the glassware with a silane, providing s... |
I know the general idea behind x-ray crystallography is to take a high quality crystal and place it in the path of an x-ray beam. Areas of high electron density will diffract the beam and lead to spots on a detector screen where photons have constructively interfered with each other (and nothing appears where destructi... |
How were x-ray diffraction patterns deciphered before computers? |
[This question][1] regarding appropriate handling of hot concentrated aqueous $\ce{NaOH}$ - with particular concern for [avoiding dissolution of borosilicate glassware][2] and contamination of the $\ce{NaOH}$ solution and other reagents - led me to think of two possible solutions:
1. Coat the glassware with a silan... |
I was checking out an extended Hückel (non-iterative) code, and realised that for s-clock elements it would be impossible to simply use atomic ionisation energies as an approximation to the orbital potential energies (due to the p orbitals being empty). In this case, what values are used?
Thanks! |
Extended Hückel Method: what are the atomic orbital energies usually used? |
I was checking out an extended Hückel (non-iterative) code, and realised that for s-block elements it would be impossible to simply use atomic ionisation energies as an approximation to the orbital potential energies (due to the p orbitals being empty). In this case, what values are used? |
Extended Hückel method: what are the atomic orbital energies usually used? |
[![enter image description here][1]][1]
With regard to whether a material is ferromagnetic or paramagnetic etc.all that I know is to check the magnetic domains and decide.However with regard to such compounds I have been facing extreme difficulties.Is this something that is totally experimental and that I need to know... |
How do I solve such questions on paramagnetism and ferromagnetism? |
> Match the type of magnetism given in Group I with the material given in Group II:
> $$
\begin{array}{ll|ll}
\hline
& \textbf{Group I} & & \textbf{Group II} \\
\hline
\text{P} & \text{Ferromagnetic} & 1 & \text{Nickel oxide} \\
\text{Q} & \text{Ferrimagnetic} & 2 & \text{Sodium} \\
\text{R} & \text{Antiferr... |
> Match the type of magnetism given in Group I with the material given in Group II:
> $$
\begin{array}{ll|ll}
\hline
& \textbf{Group I} & & \textbf{Group II} \\
\hline
\text{P} & \text{Ferromagnetic} & 1 & \text{Nickel oxide} \\
\text{Q} & \text{Ferrimagnetic} & 2 & \text{Sodium} \\
\text{R} & \text{Antiferr... |
For the transition, rhombic sulfur -> monoclinic sulfur, the value of ΔS is positive. The transition temperature increases with increase in pressure. Which is denser, the rhombic or the
monoclinic form? Prove your answer mathematically |
How to prove it mathematically? I tried by using Claypeyron equation but still failed, how should I approach and solve it. This is so tricky |
> For the transition, rhombic sulfur → monoclinic sulfur, the value of $ΔS$ is positive. The transition temperature increases with increase in pressure. Which is denser, the rhombic or the monoclinic form? Prove your answer mathematically.
I tried by using Clapeyron equation but still failed. How should I approach a... |
How to prove it mathematically that either rhombic or the monoclinic sulfur is denser? |
Instead of glassware, you might have to think about metallic containers. A 1 M NaOH should not be that harsh for stainless steel for a short period of time. Imagine, in the chlor-alkali industry, nothing is made of glass. The electrodes are made of titanium as far as I remember. If we were rich, a platinum lined crucib... |
> **Question**:
> [![enter image description here][1]][1]
<hr />
In the orange box, I think that the blue-carbon should be a carbocation instead. So, option A should be correct.
But, the answer is B. Why is it so?
[1]: https://i.stack.imgur.com/xHGqi.jpg |
Instead of glassware, you might have to think about metallic containers. A 1 M NaOH should not be that harsh for stainless steel for a short period of time. Imagine, in the chlor-alkali industry, nothing is made of glass. The electrodes are made of titanium as far as I remember. If we were rich, a platinum lined crucib... |
>I believe have found a answer.
It's valid mathematically, make sense physically but I don't know if chemically is true.
I posted to community appreciation.
There we go!
----------
**The reactions**
1. *ionization of weak acid*:
$$\ce{HA + H2O <=> H3O+ + A-}\qquad K_\ce{a}=\frac{\ce{[H3O+][A-]}}{\ce{[HA]}}... |
Is it possible that strong acids like H2SO4 behave as weaker ones like CH3COOH when the concentration is really low and vice versa for weak acid? And same question for bases.
By this I am generally referring to pH values. |
Is it possible that strong acids like H2SO4 behave as weaker ones like CH3COOH when the concentration is really high and vice versa for weak acid? And same question for bases.
By this I am generally referring to pH values. |
Is it possible that strong acids like H2SO4 behave as weaker ones like CH3COOH when the concentration is really high and vice versa for weak acid? And same question for bases.
By this I am generally referring to pH values.
Why do conc. acid react more than dilute ones. The degree of ionization of conc. acids are lowe... |
>I believe have found a answer.
It's valid mathematically, make sense physically but I don't know if chemically is true.
I posted to community appreciation.
There we go!
----------
**The reactions**
1. *ionization of weak acid*:
$$\ce{HA + H2O <=> H3O+ + A-}\qquad K_\ce{a}=\frac{\ce{[H3O+][A-]}}{\ce{[HA]}}... |
Asking from the blood barrier angle. [Wiki][1] states that Glucose, Urea, and Na/K count. Can there be any other factors, like pH, temperature, hydraulic pressure on the cell walls? Why do minerals dont play a role? Because there are only traces of them?
[1]: https://en.wikipedia.org/wiki/Plasma_osmolality |
What are the factors affecting osmosis (bio)? |
>I believe have found a answer.
It's valid mathematically, make sense physically but I don't know if chemically is true.
I posted to community appreciation.
There we go!
----------
**The reactions**
1. *ionization of weak acid*:
$$\ce{HA + H2O <=> H3O+ + A-}\qquad K_\ce{a}=\frac{\ce{[H3O+][A-]}}{\ce{[HA]}}... |
Can organic acids be concentrated and used like concentrated sulphuric acid, etc? |
Asking from the blood barrier angle. [Wiki][1] states that glucose, Uurea, and $\ce{Na/K}$ count. Can there be any other factors, like $\mathrm{pH}$, temperature, hydraulic pressure on the cell walls? Why do minerals don't play a role? Because there are only traces of them?
[1]: https://en.wikipedia.org/wiki/Pla... |
Asking from the blood barrier angle. The [wikipedia][1] states that glucose, urea, and $\ce{Na/K}$ count. Can there be any other factors, like $\mathrm{pH}$, temperature, hydraulic pressure on the cell walls? Why do minerals not play a role? Because there are only traces of them?
[1]: https://en.wikipedia.org/wi... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/Bl3hr.png
So, the picture I showed above asks for which reagents can form the ester product. I was wondering why D can't form it? I was thinking that first, the NaH would react with the carboxylic acid to form the basic form of the carboxy... |
Why can't carboxylic acid + NaH + tert butyl bromide react to create an ester? |
Instead of glassware, you might have to think about metallic containers. A 1 M NaOH solution should not be that harsh for stainless steel for a short period of time. Imagine, in the chlor-alkali industry, nothing is made of glass. The electrodes are made of titanium as far as I remember. If we were rich, a platinum lin... |
Instead of glassware, you might have to think about metallic containers. A 1 M NaOH solution should not be that harsh for stainless steel for a short period of time. Imagine, in the chlor-alkali industry, nothing is made of glass. The electrodes are made of titanium as far as I remember. If we were rich, a platinum lin... |
For $\ce{HgCl2}$ ($MW = 271.52$), the reported $\ce{Ksp}$ value [here] is $10^{-15.69}$.
This means that the calculated molar solubility of $\ce{HgCl2}$ is $(10^{-15.69}/4)^{1/3}*(271.52) \approx 0.0010$ grams per liter, or equivalently, $0.010$ grams per $100$ cubic centimeters (cc) of water.
However, in [Pubch... |
Why doesn't the expermintal molar solubility match the one calculated by the Ksp value? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/Bl3hr.png
So, the picture I showed above asks for which reagents can form the ester product. I was wondering why D can't form it? I was thinking that first, the $\ce{NaH}$ would react with the carboxylic acid to form the basic form of the ... |
Why can't carboxylic acid + NaH + tert-butyl bromide react to create an ester? |
[![enter image description here][1]][1]
In the orange box, I think that the blue-carbon should be a carbocation instead. So, option A should be correct.
But, the answer is B. Why is it so?
[1]: https://i.stack.imgur.com/xHGqi.jpg |
For $\ce{HgCl2}$ ($M = \pu{271.52 g mol-1}$), the [reported](http://www.aqion.de/site/16) $K_\mathrm{sp}$ value is $10^{-15.69}$.
This means that the calculated molar solubility of $\ce{HgCl2}$ in water is $(10^{-15.69}/4)^{1/3}\cdot\pu{271.52 g mol-1} \approx \pu{0.0010 g L-1}$, or equivalently, $\pu{0.010 g cm-3}$... |
It is the only indicator I have found that does not test below its pka, and can't think of any reason for this.
Neutral Red has a pKa value of 6.8.
(
[Reference 1](https://www.nrcresearchpress.com/doi/pdf/10.1139/v93-221),
[Reference 2](https://www.researchgate.net/post/How_long_should_one_store_neutral_red_dye)
... |
Why can Neutral Red (indicator) not test values below its pKa? |
According to AIITS exam answer key, it was given that the following compound decarboxylates on heating.
[![enter image description here][1]][1]
Then, I read [Why are beta-ketoacids better at decarboxylation than gamma or delta?](https://chemistry.stackexchange.com/questions/53879/why-are-beta-ketoacids-better-at-... |
Is it possible to make organic acids concentrated like inorganic acids like concentrated sulfuric acid and similar mineral acids?
|
Can organic acids be concentrated and used like concentrated sulfuric acid and similar mineral acids? |
I have been researching the production of peroxy acids and other strong oxidizers. I was wondering if it's possible to produce permanganic acid if I were to cast an anode containing Manganese Dioxide from a battery?
**Update**
I was able to produce what I would believe to be the permanganate anion based on the c... |
In my undergraduate Mechanisms-class the formation of 'see title' with fuming HNO3 was listed as optional knowledge in a chapter about the reactions of Enols, Enamines, etc. I cant find it in my notes, or in the recommended literature, neither can I find information on molbase, and the two papers i can find, the origin... |
Why does half-reaction with largest positive potential will run as written while other is reversed? |
Consider the metal carbonyl, Pentacarbonyl Iron(0). There exists synergic bonding between the Central Metal Atom, Iron and the neutral Carbonyl Ligands. This strengthens the metal-ligand bond but because electron density from the filled orbitals of the Iron atom is pushed into the anti bonding orbital of the C-O bond, ... |
According to AIITS exam answer key, it was given that the following compound decarboxylates on heating.
[![enter image description here][1]][1]
Then, I read [Why are beta-ketoacids better at decarboxylation than gamma or delta?](https://chemistry.stackexchange.com/questions/53879/why-are-beta-ketoacids-better-at-... |
According to AIITS exam answer key, it was given that the following compound decarboxylates on heating:
[![cyclohexane-1,2-dioic acid][1]][1]
Then, I read [Why are beta-ketoacids better at decarboxylation than gamma or delta?](https://chemistry.stackexchange.com/questions/53879/why-are-beta-ketoacids-better-at-de... |
According to AIITS exam answer key, it was given that the following compound decarboxylates on heating:
[![cyclohexane-1,2-dicarboxylic acid][1]][1]
Then, I read [Why are beta-ketoacids better at decarboxylation than gamma or delta?](https://chemistry.stackexchange.com/questions/53879/why-are-beta-ketoacids-bette... |
In semi-empirical methods, the two electron integral matrix is simplified and the entries are replaced by actual values instead of integrals to evaluate. However, while doing that, the variational principle does not seem to directly hold; in other words, you can put values in the two electron integral matrix that make ... |
What are the constraints on the two electron integral matrix? |
It makes sense that ions when dissolved in water, they still conduct electricity. Then when using the old method of the Volta Battery with a different ion dissolved in water, can it make electricity too? |
Can the Volta Battery use a different ionic solution? |
It makes sense that
water-soluble salt when dissolved in water, they conduct electricity. Then when using the old method of the Volta Battery(using copper and zinc) with a different water-soluble salt dissolved in water, can it make electricity too? |
The question is to predict the major product in following reaction
In my view this reaction will proceed via benzyne intermediate and $\ce{NH_2^-}$ will act as a base and substitute one of the chlorine. After benzyne formation as $\ce{Cl}$ is or... |
> Predict the major product in following reaction:
> [![Nucleophilic substitution in 1,4‐dichlorobenzene][1]][1]
In my view this reaction will proceed via benzyne intermediate and $\ce{NH2-}$ will act as a base and substitute one of the chlorine. After benzyne formation as $\ce{Cl}$ is *ortho*/*para* directing my... |
It makes sense that
water-soluble salt when dissolved in water, they conduct electricity. Then when using the old method of the Volta Battery(using copper and zinc) with a different water-soluble salt dissolved in water, can it make electricity too?
Plus, If I use a ammeter to check is voltage, then does all of the ... |
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