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**How Did Wittig Come to Discover Lithium-Halogen-Exchange?**
Georg Wittig, discoverer of the [Wittig reaction][1], was studying the effect of ring strain on the strength of two neighboring carbons; by adding enough strain he expected to coax C-C bonds into forming diradicals:
![diyl][2]
Unfortunately tetraphen... |
**How Did Wittig Come to Discover Lithium-Halogen-Exchange?**
Georg Wittig, discoverer of the [Wittig reaction][1], was studying the effect of ring strain on the strength of two neighboring carbons; by adding enough strain he expected to coax C-C bonds into forming diradicals:
![diyl][2]
Unfortunately tetraphen... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/vBAqX.png
Being a functional group, ethoxy should be given locant position 1, and hence this should be named : 1-Ethoxy-2,2-dimethylcyclohexane.
But, the correct name is 2-Ethoxy-1,1-dimethylcyclohexane. Can anyone please explain why is this... |
Wherever you find potassium, the isotopes are present in a set percentage that exists the same everywhere in nature, but why is that? Does it have something to do with how the element is produced? |
(a) 0.008 M $\ce{Ba(OH)2}$
(b) 0.010 M $\ce{KI}$
The answer is "a" but I do not understand why. The book says that "a" is a strong electrolyte with a total ion concentration of 0.024. How did they calculate the concentration from the information that they gave? And why is it a strong electrolyte based on that cal... |
Which solution has the highest total molarity of ions and why? |
![enter image description here][1]
[1]: https://i.stack.imgur.com/vBAqX.png
Being a functional group, ethoxy should be given locant position 1, and hence this should be named 1-Ethoxy-2,2-dimethylcyclohexane.
But, the correct name is 2-Ethoxy-1,1-dimethylcyclohexane. Can anyone please explain why this is s... |
I've read a lot about electrochromism. This <a href="http://www.academia.edu/3855995/Materials_for_Electrochromic_Devices">article</a> on electrocrhomic materials has also been additionally helpful. (I thought to put this in the Chemistry section, but it probably overlaps with physics.)
<br>I was wondering, for these ... |
[Acetone peroxide][1] is a very dangerous explosive, easily detonated by mild heating, friction or shock. It appears in the form of small white crystals.
![acetone peroxide][2]
This compound forms from the mixture of [hydrogen peroxide][3], [acetone][4] and hydrochloric or sulphuric (and maybe any other) acid. Th... |
**How Did Wittig Come to Discover Lithium-Halogen-Exchange?**
Georg Wittig, discoverer of the [Wittig reaction][1], was studying the effect of ring strain on the strength of two neighboring carbons; by adding enough strain he expected to coax C-C bonds into forming diradicals:
![diyl][2]
Unfortunately tetraphen... |
When learning about amino acids, the primary things that were pointed out were that they had an amino group and a carboxyl group, and side chain that varies from one to the other. The amino group of one can attach to the carboxyl group of another, making a peptide bond and water. Both groups are clearly important, but ... |
> When learning about amino acids, the primary things that were pointed out were that they had an amino group and a carboxyl group...
> Why amino acid? Not carboxyl acid, or some mix of the two, or something else?
You stated why it is called an amino acid, the name comes from the amine (amino) and the carboxylic ... |
what is the difference between different type of Rhodamine, for example Rhodamine Red and Rhodamine Green?
are these tow type of Rhodamine ( Red & Green ) have a good Raman signal?
we want Raman signal of these tow type of rhodamine.
thank |
What is the difference between different type of rhodamine, for example rhodamine red and rhodamine green?
are these two type of rhodamine (red & green) have a good Raman signal?
We would like examples of Raman signals of these two types of rhodamine.
|
I have a question with $\ce{NaOH}$ initially present with given concentration and conductivity, then an equal volume of given concentration of HCl is added and the final conductivity is given, again a same volume of HCl of same concentration is added, the conductivity of which is again given. Now I need to find molar c... |
I've read a lot about electrochromism. This <a href="http://www.academia.edu/3855995/Materials_for_Electrochromic_Devices">article</a> on electrochromic materials has also been additionally helpful.
<br>I was wondering, for these electrochromic materials, can you simply attach a small electrode to either side of the f... |
If we have an isolated pentane molecule at room temperature (RT) the Boltzmann energy $(E=k_\mathrm{B}T)$ is approxately $0.59\ \mathrm{kcal/mol} \overset{\wedge}{=} 207\ \mathrm{cm^{−1}}$. There is not enough energy for an electronic or vibrational excitation, so the molecule is in its electronic and vibratory ground ... |
Is it possible to reduce an acyl group to an alkane, but still keep a nitro group intact without its reduction to an amino group. A Clemmensen reduction would reduce the nitro group and it seems like other reducing agents will also reduce the nitro group to an amino group. Would some other mechanism be better suited fo... |
![enter image description here][1]
![enter image description here][2]
[1]: https://i.stack.imgur.com/fuGeT.png
[2]: https://i.stack.imgur.com/Lh8bK.png
I'm trying to reduce an aryl nitro group.
I understand that these reactions are radical reactions by the metal, but I don't understand
why alcohols ... |
Suppose you have the following voltaic cell: $\ce{Sn_{(s)}|Sn^{2+}_{(aq, 1.0 M)}||Cu^{2+}_{(aq, 1.0 M)}|Cu_{(s)}}$ and the salt bridge is $\ce{KNO_3}$. What I don't understand is why you need to have $\ce{Sn^{2+}}$ ions initially in the $\ce{Sn}$ half cell. As $\ce{Sn}$ is oxidized, electrons are supposed to travel thr... |
I have seen two different notations for **sodium acetate**. The first one is:
$$\text{NaCH}_3\text{COO}$$
The second one is:
$$\text{CH}_3\text{COONa}$$
Now I'm confused, which one is the best to use? |
> why does the enol tautomerizes to the keto form?
**In 1,3-dicarbonyl systems, like the one pictured above, we would generally expect to have a measurable amount of the enol form present**. The keto-enol interconversion is an **equilibrium** and ratio of keto and enol will be guided by **thermodynamic** factors. ... |
As ron stated in the question’s comments, none of the resonance structures display 1-methoxybuta-1,3-diene. In fact, they show an extremely unstable (if generateable) dication. Choose a random $+$, replace it with a $-$ (don’t choose the one on the oxygen) to get resonances for the structure the question asks for. That... |
What is the difference between them?
I think radial nodes and spherical nodes are the same, and angular and planar nodes are the same.
[Reference][1]
Finally, how many spherical nodes are there in a $2p$ orbital?
[1]: http://blamp.sites.truman.edu/files/2012/03/Atomic-Orbitals-PowerPoint-Pres... |
Silver tarnish is an outer coating of silver sulfide, Ag2S, formed when silver reacts with trace quantities of air-borne hydrogen sulfide, a smelly gas produced naturally by the digestion of food in living animals. Silver atoms in silver sulfide have lost electrons to sulfur atoms in creating ionic bonds. You can r... |
what is the advantage? |
Silver tarnish is an outer coating of silver sulfide, $\ce{Ag2S}$, formed when silver reacts with trace quantities of air-borne hydrogen sulfide, a smelly gas produced naturally by the digestion of food in living animals. Silver atoms in silver sulfide have lost electrons to sulfur atoms in creating ionic bonds. You ... |
Cleaning silver - which method is better? |
The question is most likely badly worded and should have been
>What is the maximum mass of $\ce{AgCl}$ that can be dissolved?
As we all know, $\ce{AgCl}$ is damn insouble in aquaeous solutions — and due to the equilibrium constant it doesn’t get better at all if you add chloride ions (reducing the silver ion conc... |
So I was "happily" doing organic chemistry homework when I came across this question:
![enter image description here][1]
I decided to take a look through my textbook to see what I was missing. The rules to compare resonance structure energies (and therefore determine relative stabilities) were in my textbook. It... |
In Paulings eqn:
% Ionic character= (1−e−(Δχ/2)2)×100
What is e?
I for the love of me can't find it anywhere |
What is the advantage of this approach over polishing the silver with an abrasive?
"Silver tarnish is an outer coating of silver sulfide, $\ce{Ag2S}$, formed when silver reacts with trace quantities of air-borne hydrogen sulfide, a smelly gas produced naturally by the digestion of food in living animals. Silver at... |
In Pauling's equation:
% Ionic character $= (1−e−(\frac{Δχ}{2})^2)×100$
What is e?
|
In Paulings eqn:
% Ionic character= (1−e−(Δχ/2)2)×100
What is e?
I for the love of me can't find it anywhere |
No, it's not epoxy *for* reinforcing steel. It's "steel reinforced epoxy."
http://www.jbweld.com/products/j-b-weld-twin-tube
How in the world does steel reinforce epoxy?
I can understand how carbon nanotubes dispersed in epoxy can help strength it, quote from paper below:
> The mechanical behavior of mult... |
I have this idea of creating a large domed ceiling/roof for a building that can be made clear to see the actual sky, or made fully opaque/dark grey/black to project an artificial sky onto.
I know that things similar to this effect have been chemically achieved such as UV-activated sun glasses and remote controlled ... |
Is there a known chemical that makes it possible to control opacity of a large surface? |
I have this idea of creating a large domed ceiling/roof for a building that can be made clear to see the actual sky, or made fully opaque/dark grey/black to project an artificial sky onto.
I know that things similar to this effect have been chemically achieved such as UV-activated sun glasses and remote controlled ... |
what is that process called in which we add the water molecules to an ion to form a complex? |
I have this idea of creating a large domed ceiling/roof for a building that can be made clear to see the actual sky, or made fully opaque/dark grey/black to project an artificial sky onto.
I know that things similar to this effect have been chemically achieved such as UV-activated sun glasses and remote controlled ... |
In Paulings eqn:
$$ \%~\ce{ionic~character} = \left[ 1−e^{−(Δχ/2)^2}\right] \times 100$$
What is $e$?
I for the love of me can't find it anywhere |
This equation has been described as an equilibrium in an article, how would you explain it to someone with not a lot of understanding of it.
The equation is:
CH3COOH <-> Ch3COO- + H+
Although the description is of an equilibrium, it can be clearly seen that it is a resonance arrow.So how would you describe it? |
How would you describe this? |
This equation has been described as an equilibrium in an article, how would you explain it to someone with not a lot of understanding of it.
The equation is:
$\ce{CH3COOH <-> Ch3COO- + H+}$
Although the description is of an equilibrium, it can be clearly seen that it is a resonance arrow.So how would you describ... |
This equation has been described as an equilibrium in an article, how would you explain it to someone with not a lot of understanding of it.
The equation is:
$\ce{CH3COOH <-> CH3COO- + H+}$
Although the description is of an equilibrium, it can be clearly seen that it is a resonance arrow.So how would you describ... |
An example would be $\ce{[Fe(H2O)6]^2+}$ in which it has 6 water molecules associated with it. What is the process of adding these water molecules called? |
What is that process called in which we add water molecules to an ion to form a complex? |
Is it possible to derive the nuclear spin I=3/2 for $\ce{^23Na}$ from a term scheme or from something else from spectroscopy?
I was asked this question in an old exam and didn't know how to do it. I thought the nucleus spin is empirical (and cannot be calculated from J and F values) or does it? |
Why R32 Space Group is named this? "R" stand for Rhombohedral, "3" for Threefold Axis, and "2"? I don't see any Twofold Axis in the cell:
http://img.chem.ucl.ac.uk/sgp/large/155az1.htm |
They are both formed when a liquid is supercooled rapidly, no free energy, and they both have irregular structures. What defines a glass other than how it is amorphous, transparent, and has a glass transition state? |
What is the difference between an amorphous solid and glass? |
In several metabolic pathways, the Nature (live systems) chooses to make esterification using thioesters (CoA) and not esters. I would like to know what is the main aim of the Nature with this choice: faster reactions or more extensive reactions? |
**Requirements**
In short, I am looking for a fluid that meets these criteria:
- Hydrophobic
- Denser than water
- Low viscosity
- Food safe
**Background**
We are working on adding a pool and designing a backyard recreational area. One design element that we would like to include in multiple place... |
Is there a food-safe hydrophobic liquid with a substanially higher denisty than water? |
Would it be right to say
a) The ortho and para positions are more active than the meta position
OR
b) The ortho and para positions are activated while the meta position is deactivated? |
In the dipole approximation the following relation holds:
$\hat{V}=-\hat{\mu}\overrightarrow{E}$.
When we say "approximation" I guess we want to point out, we are dealing with linear spectroscopy, where we have the polarizability of the molecule proportional to the electric susceptibility of a molecule:
$\ov... |
Why do we say approximation in the dipole approximation in spectroscopy? |
I see heats of combustion given in kg [dot] calories per gram (Handbook of Chemistry and Physics, 1969-1970). I don't know how that makes sense, as I don't know what a kg cal might be. I would have expected units of energy per mass (calories per gram) or energy per mole. What is a kg cal, and what is wrong in my thin... |
What is a kg.cal per gram, as a heat of combustion? |
Which of the statements below is correct?
>a) The ortho and para positions are more active than the meta position.
OR
>b) The ortho and para positions are activated while the meta position is deactivated. |
Our professor only told us that A is favored, and B is not getting formed. I thought about the resonance structures and saw a contradiction to that what the prof told us. To be honest I think my argument with the resonance structure is not strong enough, because it does not explain the prefered product. Why is structur... |
Which of the statements below is correct?
>a) The ortho and para positions are more active than the meta position.
Or
>b) The ortho and para positions are activated while the meta position is deactivated. |
Why R32 Space Group is so named? I mean, if *R* stands for Rhombohedral and *3* for Threefold Axis, what 2 stands for?
I don't see any Twofold Axis in the cell:
http://img.chem.ucl.ac.uk/sgp/large/155az1.htm |
I see heats of combustion given in kg [dot] calories per gram molecular weight (Handbook of Chemistry and Physics, 1969-1970). I don't know how that makes sense, as I don't know what a kg cal might be. I would have expected units of energy per mass (calories per gram) or energy per mole. What is a kg cal, and what is... |
One such article that I found was published by the University of South Florida. The abstract for which reads:
>Given a set of differential equations describing blood alcohol content as a function time, we integrated the
equations to obtain a general solution. The general solution equation depends on three free para... |
Does anyone know any good references which use partial differential equations to model the alcohol concentration in the bloodstream? I'm a mathematician, so I'm searching for a rigorous mathematical model.
If you have any other suggestions of models in chemistry that uses partial differential equations, feel free t... |
Here's the equation:
∆*S* = \frac{∆*Q*}{*T*}
The confusion I have with this equation lies in the variable for temperature, *T*. Why is the temperature constant in this equation? Why can't the equation include ∆*T* instead of just *T*, and, surely, if ∆*q* is negative or positive the temperature must decrease o... |
Can someone explain the equation for entropy:? |
Here's the equation:
∆*S* = $\frac{∆q}{T}$
The confusion I have with this equation lies in the variable for temperature, *T*. Why is the temperature constant in this equation? Why can't the equation include ∆*T* instead of just *T*, and, surely, if ∆*q* is negative or positive the temperature must decrease or in... |
> what is the main aim of the Nature with this choice: faster reactions
> or more extensive reactions?
**Nature is cheap**, its main aim is to spend as little energy as possible in a chemical reaction. **Nature will always evolve so as to use the lowest energy pathway**.
If we compare the resonance structures f... |
In several metabolic pathways, Nature (live systems) chooses to make esterification using thioesters (CoA) and not esters. I would like to know what is the main aim of the Nature with this choice: faster reactions or more extensive reactions? |
Which of the statements below is correct?
>a) The *ortho* and *para* positions are more active than the *meta* position.
Or
>b) The *ortho* and **para** positions are activated while the *meta* position is deactivated. |
I have this idea of creating a large domed ceiling/roof for a building that can be made clear to see the actual sky, or made fully opaque/dark grey/black to project an artificial sky onto.
I know that things similar to this effect have been chemically achieved such as UV-activated sun glasses and remote controlled ... |
Is there a known chemical that makes it possible to control the opacity of a large surface? |
Here's the equation:
$\Delta S = \frac{\Delta q}{T}$
The confusion I have with this equation lies in the variable for temperature, $T$. Why is the temperature constant in this equation? Why can't the equation include $\Delta T$ instead of just $T$ and, surely, if $\Delta q$ is negative or positive the temperatur... |
Can someone explain the equation for entropy? |
Are there any type of detergent/surfactant chemicals that would be good for removing dirt and grease from fabric that also would evaporate from the clothes within, say, 24 hours leaving no residue? |
Is there a type of detergent/surfactant that evaporates at STP? |
I would like to ensure that my hydrangeas are blue. I am told that adding ammonium sulfate or aluminum sulfate will cause the soil to be more acidic. I am also told that adding elemental sulfur will help. Will adding magnesium sulfate to the soil help? |
It seems like the typical laboratory methods for determining the carbon content of steel are to cuppellate it in a stream of oxygen and then measure the volume of the evolved CO and CO2, which involves many high-temperature complexities.
Why can't the carbon content of steel be measured by dissolving it in acid and ... |
can anyone explain to me that how solvent factor affect the wavelength and intensity of gold nanoparticle and silver nanoparticle in UV spectroscopy? Thank you so much. |
Solvent effect on gold nanoparticle and silver nanoparticle in UV spectroscopy? |
can anyone tell me the difference between absorption spectroscopy and extinction spectroscopy in terms of experiment? and how to get extinction spectroscopy, how to get absorption spectroscopy? Thank you so much. |
Can anyone explain to me that how solvent factor affect the wavelength and intensity of gold nanoparticle and silver nanoparticle in UV spectroscopy? |
[Slide 28, How would I create an Ice table and what numbers do I use to solve this? Thank you.][1]
[1]: http://learning.hccs.edu/faculty/steven.dessens/notes_and_practice/chem_1412/chem-1412-zumdahl-powerpoints/chapter-13-chemical-equilibrium/at_download/file |
Equilibrium concentration, Where does the 5.00 for FeSCN^2+ comes from, and how do you solve this problem? |
It seems like the typical laboratory methods for determining the carbon content of steel are to cuppellate it in a stream of oxygen and then measure the volume of the evolved $\ce{CO}$ and $\ce{CO2}$, which involves many high-temperature complexities.
Why can't the carbon content of steel be measured by dissolving i... |
I know when a hydrogen bond is, but - can hydrogen bonds only occur between two molecules containing hydrogen ? Or , only one of the molecules should contain hydrogen and the other one may not contain hydrogen, but should have a large electronegative difference between two of its sides ?
Thanks in advance |
I know when a hydrogen bond is, but - can hydrogen bonds only occur between two molecules containing hydrogen? Or, only one of the molecules should contain hydrogen and the other one may not contain hydrogen, but should have a large electronegative difference between two of its sides?
|
What are the prerequisites in hydrogen bonding? |
Actually, theoretically speaking hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge. A hydrogen bond may... |
As ron stated in the question’s comments, none of the resonance structures display 1-methoxybuta-1,3-diene. In fact, they show an extremely unstable (if generateable) dication. Choose a random $+$, replace it with a $-$ (don’t choose the one on the oxygen) to get resonances for the structure the question asks for. That... |
With higher period the d-electrons of the metal are less strong bonded and therefore oxidative addition is easier for $\ce{Ir(I)}$ than for $\ce{Rh(I)}$ and much easier than for $\ce{Co(I)}$.
For metal carbonyl hydride: electrons with higher period (5d) are stronger bound to the nucleus, so pKa is increasing in this... |
Is it possible to say water vapour and dew is same. I know that the water vapour is the gaseous phase of the water. But what is the dew. I just wonder how can I categorised it.Is it liquid or the gas phase of the water.
Figure below shows dew formed in grass. It seems as a liquid. But is it actually exhibit in li... |
Is it possible to say water vapour and dew is the same? I know that the water vapour is the gaseous phase of water. But what is the dew? I just wonder how can I categorised it. Is it the liquid or the gas phase of the water.
Figure below shows dew formed in grass. It seems as a liquid. But is it actually exhibit i... |
Is dew and water vapour the same? |
In my group’s seminar last Friday, we discussed the total synthesis of 6-demethyl-6-deoxytetracycline **1** by Woodward *et al.*<sup>[1]</sup> One intermediate of their synthesis is *meta*-substituted anisole **2** that they subsequently wish to cyclise to create the first two rings of **1** by a Friedel-Crafts acylati... |
Is the para-position of anisoles more reactive than ortho in electrophilic substitutions? |
Question: When propane reacts with chlorine, two different monochloropropanes are formed.
a.) name and show the full structural formulae of the two products.
b.) what kind of isomerism is shown?
Thanks in advance.
|
Question: When propane reacts with chlorine, two different monochloropropanes are formed.
>a.) name and show the full structural formulae of the two products.
b.) what kind of isomerism is shown?
|
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