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Enolate formation: Do we get the cis or trans enolate? |
I'm wondering since months concerning the addition of a base of type $\ce{NR_3}$ (R: alkyl) to a ketone (e.g. heptan-4-one).
I didn't find any internet page which studies this question in detail, that's why I'm asking my question here. I'm thinking about four easy cases:
a) $\ce{NMe_3}$ (small)
b) $\ce{NMeEt_2... |
Does the addition of a base NR3 to a ketone affords the cis or the trans enolate? |
The convention used by many is that *ab initio* refers solely to wave-function based methods of various sorts and that *first principles* refers to either wave-function or DFT methods with little approximation.
I can't find a citation at the moment, but I know this convention is fairly widely used in, e.g., *J. Phys... |
First note that the acronym DFA I used in my comment originates from Axel D. Becke paper on 50 year anniversary of DFT in chemistry:
> Let us introduce the acronym DFA at this point for “density-functional
> *approximation*.” If you attend DFT meetings, you will know that Mel
> Levy often needs to remind us that D... |
![enter image description here][1]
Esters of catechol undergo the **Fries rearrangement**
But one product is formed more than the other.
I believe it is due to the electron withdrawing nature of the $\ce{OCOCH3}$ group which prefers the attack on meta position.I was able to write a reaction mechanism for th... |
The following [comment][1] by Wildcat made me think about whether density functional theory (DFT) can be considered an *ab initio* method.
> @Martin-マーチン, this is sort of nitpicking, but DFT (where the last "T" comes from "Theory") can be considered as an ab-initio method since the theory itself is built from the fi... |
Why should the enthalpy of a reaction be defined at constant pressure. Why can't it be defined at variable pressure? |
Is enthalpy of a reaction meaningful at variable pressure? |
Hemoglobin is an iron-containing oxygen transport metalloprotein in the red blood cells of most mammalians. Simply put it's a carrier protein. Interestingly it doesn't carry carbon dioxide the same way it does for oxygen $\ce{O2}$. Oxygen binds to the iron atoms in the protein where as cabon dioxide $\ce{CO2}$ is bound... |
Why carbon monoxide has a greater affinity for Hemoglobin compared to oxygen? |
First note that the acronym DFA I used in my comment originates from Axel D. Becke paper on 50 year anniversary of DFT in chemistry:
> Let us introduce the acronym DFA at this point for “density-functional
> *approximation*.” If you attend DFT meetings, you will know that Mel
> Levy often needs to remind us that D... |
Hemoglobin is an iron-containing oxygen transport metalloprotein in the red blood cells of most mammalians. Simply put it's a carrier protein. Interestingly it doesn't carry carbon dioxide the same way it does for oxygen $\ce{O2}$. Oxygen binds to the iron atoms in the protein whereas carbon dioxide $\ce{CO2}$ is bound... |
First note that the acronym DFA I used in my comment originates from Axel D. Becke paper on 50 year anniversary of DFT in chemistry:
> Let us introduce the acronym DFA at this point for “density-functional
> *approximation*.” If you attend DFT meetings, you will know that Mel
> Levy often needs to remind us that D... |
>Why should the enthalpy of a reaction be defined at constant pressure? Why can't it be defined at variable pressure?
Not sure "should" is the right choice of words: It can be defined for a reaction either at constant volume (variable pressure) or constant pressure (variable volume). You might choose one measurement... |
First note that the acronym DFA I used in my comment originates from Axel D. Becke paper on 50 year anniversary of DFT in chemistry:
> Let us introduce the acronym DFA at this point for “density-functional
> *approximation*.” If you attend DFT meetings, you will know that Mel
> Levy often needs to remind us that D... |
> … catalysis, the acceleration of chemical reactions by substances not consumed in the reactions themselves—substances known as catalysts.
([Source](http://global.britannica.com/science/catalysis))
Now as I’ve understood, to keep a reaction going, you must keep the solution heated and sometimes add more of the c... |
>Why should the enthalpy of a reaction be defined at constant pressure? Why can't it be defined at variable pressure?
Not sure "should" is the right choice of words: It can be defined for a reaction either at constant volume (variable pressure) or constant pressure (variable volume). You might choose one measurement... |
The answer has to do with [pi-backbonding][1].
In essence, the CO molecule has a negative formal charge on the carbon (it's neutral because of the oxygen having a positive formal charge). However, C is quite electropositive, and would like to relieve the stress caused by the negative formal charge. To relieve the s... |
What is the structure and preparation for bleaching powder? Why there is a **controversy** in the formula of bleaching powder?
I have encountered many forms of the formula of bleaching formula, like
1. Ca(OCl)2 - wikipedia
2. CaOClCl - my textbook
3. ![enter image description here][1]
here the product is... |
What is the structure and preparation for bleaching powder? Why there is a **controversy** in the formula of bleaching powder?
I have encountered many forms of the formula of bleaching powder, like
1. Ca(OCl)2 - wikipedia (it also mentions that bleaching powder is rather a mixture having other calcium compound... |
What is the structure and preparation for bleaching powder? Why there is a **controversy** in the formula of bleaching powder?
I have encountered many forms of the formula of bleaching powder, like
1. $\ce{Ca(OCl)2}$ - wikipedia (it also mentions that bleaching powder is actually a mixture having other calcium... |
Why does the left molecule in the picture undergo hydrogenolysis of the C-N bond readily while the right molecule doesn't react at all?
![enter image description here][1]
[1]: https://i.stack.imgur.com/fTO7u.gif |
Recently, while cleaning a neighbour's fridge (turned off for a few weeks), I came across a cup (closed with a lid). Inside the cup was, to my olfactory horror, congealed milk, with a steel (iron) teaspoon nicely wedged into it.
The milk had separated into a blue cheese-like solid, overlain with a semi-translucent ... |
After seeing one too many TV commercial about the fantastical properties of different high-profile shampoo products all "with documented effect" it suddenly struck me that I never actually researched what the active ingredients of a shampoo really is.
So what are the active ingredients of most shampoos, and how do t... |
What are the active ingredients of shampoo, and how do they work? |
I actually tested submerging a bunch of old rusty knives blades in a cup of plain cola for a few days not expecting much. To my amazement the myth held true, coke is a really good rust remover.
So what is the chemistry behind it? |
What makes cola efficient as a rust remover? |
Suppose I have a group of organic compounds say A, B, C, D, E, F, G, H. I know their chemical formula and their names. Now there exists a reaction among these compounds but we do not know which compounds would react to give which products. It may be that A and B react to give C and D or B and D react to give F and H. I... |
What the question says. For example, if I knew the specific heat capacities of lithium and oxygen, could I work out the specific heat capacity of lithium oxide with no further information? |
Is it possible to calculate specific heat capacity of a compound based on its elements' heat capacities? |
In meta hydroxy benzaldehyde which position (w.r.t hydroxy group) is more prone to electrophilic attack ?
My approach:I considered hydroxy group as the stronger +M group.So my guess was para position w.r.t hydroxy group.But that's not the correct answer.
Help please!
|
In meta hydroxy benzaldehyde which position (w.r.t hydroxy group) is more prone to electrophilic attack ? |
In meta hydroxy benzaldehyde which position (w.r.t hydroxy group) is more prone to electrophilic attack ?
My approach:I considered hydroxy group as the stronger +M group.So my guess was para position w.r.t hydroxy group.But that's not the correct answer.
|
In meta hydroxy benzaldehyde which position (w.r.t hydroxy group) is more prone to electrophilic attack? |
In meta hydroxy benzaldehyde which position (w.r.t hydroxy group) is more prone to electrophilic attack ?
My approach:I considered hydroxy group as the stronger +M group.So my guess was para position w.r.t hydroxy group.But that's not the correct answer.
The answer is actually given as ortho w.r.t hydroxy and pa... |
My textbook says that for a d-electron, the orbital angular momentum is $$ \frac{\sqrt{6}n}{2\pi} $$
But since:-
$$ mvr = \frac{nh}{2\pi}$$
$$ n \in N$$
So how come the value of n is an irrational number? |
How come the value of principal quantum number is an irrational number? |
My textbook says that for a d-electron, the orbital angular momentum is $$ \frac{\sqrt{6}n}{2\pi} $$
But since:-
$$ mvr = \frac{nh}{2\pi}$$
$$ n \in N$$
where N is the set of natural numbers.
So how come the value of n is an irrational number? |
Studying biochemistry I noticed that equilibrium is reached for K and Na separately (not taking into account electric potential), as would be the case I assume for any molecule or atom. This is of course entropy.
Eg: My understanding is, you have two types of atoms, and a membrane separating them, with different con... |
Please tell me which one is true?
1. px orbital: m = -1 , py orbital: m = 0 , pz orbital: m = +1
2. py orbital: m = -1 ; pz orbital: m = 0 ; px orbital: m = +1
Please tell me which one is true and mention your references. |
What's the magnetic quantum number for p orbitals? What's for px , py, and pz if looked a seperately? |
How to find the central atom? What is the central atom in $\ce{PCl3}$
and how to find the shape using VSEPR theory? |
How to know which atom is the central atom in VSEPR theory? |
Studying biochemistry I noticed that equilibrium is reached for K and Na separately (not taking into account electric potential), as would be the case I assume for any molecule or atom. This is of course entropy.
Eg: My understanding is, you have two types of atoms, and a membrane separating them, with different con... |
My textbook says that for a d-electron, the orbital angular momentum is $$ \frac{\sqrt{6}h}{2\pi} $$
But since:-
$$ mvr = \frac{nh}{2\pi}$$
$$ n \in N$$
where N is the set of natural numbers.
So how come the value of n is an irrational number? |
We know the the atomic radii increase down the group. So less energy is required to pull the outermost electron as we go down the group and gradually melting points decreases down the group. The topmost element has large m.p because of small atomic radii and so more energy is required to pull the outermost electron. Bu... |
Negative of the $\Delta G$ for a process is the maximum useful work that can be obtained from it (at constant pressure and temperature). I understood this in this way: $\Delta H$ is the heat absorbed by the system (since the process is at constant temperature and pressure), so equivalently $-\Delta H$ energy is obtain... |
I noticed the fact that all the hydrides of the elements belonging to group IV has bond angle 109.5° while in group V it varies from 107.3°for NH3 to 91.3°for SbH3. Similarly we see in group VI that water has highest bond angle then it significantly decreases to 89.5° for H2Te. Is there any specific reason for hydride... |
What chemicals govern the stench emanating from socks? If it's just sweat, why don't underwear or vests stink as much? Which gas am I inhaling when smelling socks to decide whether they need a wash? |
Why do socks stink? |
**The question is :-**
The ionization energy of $He^+$ is $19.6 \times 10^{-18}J$ $atom^{-1}$. What is the energy of the first stationary state (n=1) of $Li^{2+}$?
Since the question specifically states that n=1, I used the forumula $E = -2.178 \times 10^{-18} \frac{Z^2}{n^2}$
So $$E = -2.178 \times 10^{-18} .... |
Sometimes I feel the water in the pool is heavily chlorinated. However it is impossible for me to swim without ingesting some water. I am only a learner but even advanced swimmers do concede that they do ingest some water at times.
Could this be potentially harmful depending on the chemical content in the pool? Are ... |
Is ingesting water during swimming harmful? |
I have a collection of old to very old books (all 80+ years old), recently, I received a British Chemistry textbook from 1902 - one thing I notice is that there is a distinct smell that comes from the pages of older books.
**What is the chemistry behind the old pages in a book smell?** |
What causes the old book smell? |
What chemicals are responsible for the stench emanating from socks? If it's just sweat, why don't underwear or vests stink as much? Which gas am I inhaling when smelling socks to decide whether they need a wash? |
In my previous question, someones answer among other things, said that boiling the water increases the concentration of nitrates and nitrites. I searched on google and it's true, but how does that happen ? What is the reaction that leads to an increasing level of nitrates?
Im very courious because nitrates are too da... |
>Could this be potentially harmful depending on the chemical content in the pool?
Probably not, unless you managed to drink quite a bit of pool water. Worldwide, millions (hundreds of millions?) of people have collectively ingested millions (billions?) of liters of pool water - with varying chemistries - over many d... |
>boiling the water increases the concentration of nitrates and nitrites.
Yes.
>how does that happen? What is the reaction that leads to an increasing level of nitrates?
It happens because you boil away the water, and the nitrates and nitrites stay in what's left of the water, thus raising the concentration of ... |
I am attempting to begin synthesizing glucose, however I will require a form of ball milled cellulose as a main ingredient. Having been said, what methods would be recommended to create the Cellulose? If we were to use grass clippings or cotton as our source for example, what steps would we take in order to gain the de... |
How Does One Create A Cellulose Ingredient For Use In The Creation Of Glucose? |
I know an isotherm is a line of constant temperature.
Isobar is a constant pressure line.
Isentrope is a line of constant entropy.
But what do you call a line of constant volume? An Isochore?
And what do you call a line of constant enthalpy? An "isenthalp"? |
What is the proper term for lines of constant volume and constant enthalpy on a thermodynamic diagram? |
>But what do you call a line of constant volume? An Isochore?
Correct.
>And what do you call a line of constant enthalpy?
The process is isenthalpic. More than one engineering/thermodynamic text I found by Googling indicates they are simply referred to as "isenthalpic lines." See [this](https://books.google.co... |
I noticed the fact that all the hydrides of the elements belonging to group IV has bond angle 109.5° while in group V it varies from 107.3° for $\ce{NH3}$ to 91.3° for $\ce{SbH3}$. Similarly we see in group VI that water has highest bond angle then it significantly decreases to 89.5° for $\ce{H2Te}$. Is there any speci... |
I've read somewhere on the Internet that burning graphite at 4200K with a sufficiently high pressure would turn it into diamond.
This chart seems to support this idea: ![enter image description here][1]
Is that doable industrially?
[1]: https://i.stack.imgur.com/kOO8B.png |
Is turning graphite carbon to diamond industrially doable? |
I've read somewhere on the Internet that burning graphite at 4200°K at a sufficiently high pressure would turn it into diamond.
This chart seems to support this idea: ![enter image description here][1]
Is that doable industrially?
[1]: https://i.stack.imgur.com/kOO8B.png |
Is turning graphite carbon into diamond industrially doable? |
I've read somewhere on the Internet that heating graphite at 4200°K at a sufficiently high pressure would turn it into diamond.
This chart seems to support this idea: ![enter image description here][1]
Is that doable industrially?
[1]: https://i.stack.imgur.com/kOO8B.png |
You want to **heat** graphite at high pressure, not burn it - but yes, high-T, high-p will work.
>Is that doable industrially?
There is a rather lengthy and informative Wikipedia article for [synthetic diamond](https://en.wikipedia.org/wiki/Synthetic_diamond) that illustrates (in part) the use of this process - ... |
[Cotton wool][1], also called "purifie3d cotton", is inexpensive and available at pharmacies ("chemists" in the UK). I could not find the percentage of impurities (probably lignin and minerals), but it is considered [one of the purest forms of cellulose commercially available.][2], and should not need pretreatment to m... |
Determine the equivalence ratio of the following mixture: 4g of Butane, C4H10 and 75 grams of air.
Answer is 0.82
Ok so I try converting everything into mols
4gC4H10 * (1mol/58g) = 4/58 mol
75gAir * (1mol/28.966g) = 75/28.966 mol
air-fuel ratio = ( 75/28.966 )/( 4/58 ) = 37.54 (ok this is just a guess th... |
Notation of the reduction and oxidation of copper typically includes the aqueous state. Illustrated bellow:
$$\ce{Cu(s) -> Cu2+(aq) + 2e-}$$
This event usually occurs at 0.34V. What if the copper was in an organic environment instead? I ask because I am doing Cyclic Voltamettry of a capacitor with copper as the curre... |
Will oxidation/reduction of copper still occur in an electrochemical cell if it is not in an aqueous enviroment? |
Determine the equivalence ratio of the following mixture: 4g of Butane, $\ce{C4H10}$, and 75 grams of air.
Answer is 0.82
Ok so I try converting everything into mols
$4~\mathrm{g}~(\ce{C4H10}) \times \frac{1~\mathrm{mol}}{58~\mathrm{g}} = \frac{4}{58}~\mathrm{mol}$
$75~\mathrm{g~(Air)} \times \frac{1~\mathr... |
**The question is :-**
The ionization energy of $\ce{He+}$ is $19.6 \times 10^{-18}~\mathrm{J~atom^{-1}}$. What is the energy of the first stationary state ($n=1$) of $\ce{Li^{2+}}$?
Since the question specifically states that $n=1$, I used the formula $E = -2.178 \times 10^{-18} \frac{Z^2}{n^2}$
So $$E = -2.1... |
[Cotton wool][1], also called "purified cotton", is inexpensive and available at pharmacies ("chemists" in the UK). I could not find the percentage of impurities (probably lignin and minerals), but it is considered [one of the purest forms of cellulose commercially available][2], and should not need pretreatment to mak... |
Notation of the reduction and oxidation of copper typically includes the aqueous state. Illustrated below:
$$\ce{Cu(s) -> Cu^2+(aq) + 2e-}$$
This event usually occurs at 0.34 V. What if the copper was in an organic environment instead? I ask because I am doing cyclic voltammetry of a capacitor with copper as the curr... |
![enter image description here][1]
Esters of catechol undergo the **Fries rearrangement**
But one product is formed more than the other.
I believe it is due to the electron withdrawing nature of the $\ce{OCOCH3}$ group which prefers the attack on meta position.I was able to write a reaction mechanism for th... |
I have a collection of old books (all 80+ years old), recently, I received a British Chemistry text from 1902 - one thing I notice is that there is a distinct smell that comes from the pages of older books. (the smell is not unpleasant).
**What is the chemistry behind the old pages in a book smell?** |
As a continuation to the question: <br>
http://chemistry.stackexchange.com/questions/33763/predicting-reaction-among-compounds?noredirect=1#comment51084_33763 <br><br>
I found the list of functional group on wikipaedia:<br>
https://en.wikibooks.org/wiki/Organic_Chemistry/Overview_of_Functional_Groups <br><br>
Now i... |
As a continuation to the question: <br>
http://chemistry.stackexchange.com/questions/33763/predicting-reaction-among-compounds?noredirect=1#comment51084_33763 <br><br>
I found the list of functional group on wikipaedia:<br>
https://en.wikibooks.org/wiki/Organic_Chemistry/Overview_of_Functional_Groups <br><br>
Now i... |
As a continuation to the question: <br>
http://chemistry.stackexchange.com/questions/33763/predicting-reaction-among-compounds?noredirect=1#comment51084_33763 <br><br>
I found the list of functional group on wikipaedia:<br>
https://en.wikibooks.org/wiki/Organic_Chemistry/Overview_of_Functional_Groups <br><br>
Now i... |
Why does the color of the halogens deepens as we go down the group? also why there is a change in physical state of halogens down the group?
fluorine - very pale yellow gas (almost invisible to naked eye)
chlorine - yellow green gas
bromine - red-brown liquid
iodine - violet-black solid |
What is the chemistry behind the bad smell of human perspiration? also what is its composition? |
What is the smell of human perspiration(sweat)? |
I have a collection of old books (all 80+ years old), recently, I received a British Chemistry text from 1903 - one thing I notice is that there is a distinct smell that comes from the pages of older books. (the smell is not unpleasant).
**What is the chemistry behind the old pages in a book smell?** |
What is the chemistry behind smell of human perspiration(sweat)? |
> Why does sweat smell?!
Sweat released from sweat glands **odourless.** Bad smell of sweat is due to certain bacteria on your skin mix with sweat(That is why sweat smell bad after sometime) and also due to certain hormones released during puberty.
I have tried my best to keep this part chemistry point of view(A... |
I have a collection of old books (all 80+ years old), recently, I received a British Chemistry text from 1903 (intro page below):
![enter image description here][1]
One thing I notice is that there is a distinct smell that comes from the pages of older books. (the smell is not unpleasant).
**What is the chemi... |
Why does the color of the halogens deepens as we go down the group? also why there is a change in physical state of halogens down the group?
\begin{array}{c|c}
\mathbf{Gas} & \mathbf{Color} \\\hline
\ce{F} & \mathrm{very~pale~yellow~(almost~invisible~to~naked~eye)}\\
\ce{Cl} & \mathrm{yellow-green~} \\
\ce{Br} &... |
Often (or always?) one enantiomer of a certain drug will be effective and the other ineffective or harmful. The famous example is of course Thalidomide where one enantiomer caused mutilation of the unborn child and the other relieved morning sickness. Are there any other examples where the enantiomer of a drug that is ... |
In my chemistry textbook, it is written that :
>Gibbs energy for a reaction in which all reactants and products are in standard state, $\Delta _rG^○$ is related to the equilibrium constant of the reaction as follows:
$$\Delta _rG^○=-\ce{RTlnK}$$
A solved example was given there for the above equation.
> Calculate $\... |
In my chemistry textbook, it is written that :
>Gibbs energy for a reaction in which all reactants and products are in standard state, $\Delta_\mathrm{r}G^\circ$ is related to the equilibrium constant of the reaction as follows:
$$\Delta_\mathrm{r}G^\circ=-RT\ln K$$
A solved example was given there for the above ... |
My textbook says: 'It is appropriate to remark that the trick of rationalizing apparent violations of the octet rule by invoking the participation of d-orbitals in the bonding scheme is a matter of some controversy. Some scientists feel that the d-orbitals lie so high in energy that they should not be treated as valenc... |
Can d-orbitals participate in bonding? |
My textbook says:
> It is appropriate to remark that the trick of rationalizing apparent violations of the octet rule by invoking the participation of d-orbitals in the bonding scheme is a matter of some controversy. Some scientists feel that the d-orbitals lie so high in energy that they should not be treated as val... |
After reading [this][1] recent question I was interested in how to calculate the specific heat capacity of a mixture based on the specific heat capacities of its components.
According to [this][2] website the specific heat capacity of an ideal mixture is given by $$C_{p(\mathrm{mixture})} = \sum\limits_iC_{p(i)}x_i$... |
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