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I would like to ask a question about mathematical derivation of the HF equations. Some moments related to the functional variation are not clear for me.
I read a book of Szabo and Ostlund "Modern quantum chemistry". There the procedure of the Single determinant energy minimization is presented. Omitting the whole proc... |
How is this molecule chiral?
$(Br)HC=C=CH(Cl)$
My thoughts: I know that chiral carbons have different groups attached to it. Here the end carbons have two different groups and a double bond. But, how does this double bond specify different groups? |
How is this molecule chiral? |
Why are allenes chiral? |
How is this molecule chiral?
$(Br)HC=C=CH(Cl)$
My thoughts: I know that chiral carbons have different groups attached to it. Here the end carbons have two different groups and a double bond. But, how does this double bond specify different groups?
This questions is from Ochem.com and its answer(of being chiral... |
A solution prepared by dissolving 2.8 gm of lime, CaO in enough water to make 1.00 L of lime water (Ca(OH)2(aq.)). If solubility of Ca(OH)2 in water is 1.48 gm. The pH of the solution obtained will be:
[log 2 = 0.3, Atomic masses are Ca = 40 , O = 16, H = 1]
[Note : Ca(OH)2 is considered to be a weak base because... |
A solution prepared by dissolving $2.8 g$ of lime, $\ce{CaO}$ in enough water to make $1.00 l$ of lime water ($\ce{Ca(OH)_{2(aq)}}$). If solubility of $\ce{Ca(OH)2}$ in water is $1.48 g$. The $p\ce H$ of the solution obtained will be:
[$\log 2 = 0.3$, Atomic masses are $\ce Ca$ = $40$ , $\ce O$ = $16$, $\ce H$ = $1$... |
I want some information regarding the protocol for determining any type of impurity in pharmaceutical substances or drug product.
Which type of impurities can be identified by HPLC and MS?
what is the difference between related substances and impurity? |
which are the possible ways to detect impurity in drugs? |
My attempt:Based on symmetry:I think that looking for symmetry phenol has higher boiling point than 1,2-dihydrobenzene because the two -OH groups projecting out from he benzene ring of 1,2-dihydrobenzene will not allow close packing of them which results in less boiling point.
Based on hydrogen bonding:In this sens... |
Which among phenol and 1,2-dihydrobenzene have more boiling point? |
It depends a little on your definition of combustion.
Most combustion we see involves things reacting with the oxygen in air. Most combustion reactions are a self-sustaining exothermic reaction of some substance with oxygen gas. But atmospheric oxygen is relatively dilute (only about 21% of air is oxygen) and this ... |
The stoichiometric defects ([Schottky][1] and [Frenkel][2] defects) in ionic crystals are formed due to irregularities in ionic arrangement all the while maintaining the stoichiometry and electric neutrality. It is a fact that $\ce{AgBr}$ shows both Frenkel and Schottky defects while most other compounds show only one... |
How to calculate it? I know that it depends on the coordination compound and the number of electrons present in t2g and eg orbitals and the final answer is expressed in terms of crystal field splitting parameter. But, how to know how many electrons are there in t2g and eg orbitals?
I think rather than a broad answer... |
How to calculate crystal field stabilisation energy? |
I've recently read that the Carbon takes a unique position as a reducing agent , and i think it has to do with the very special form of its Ellingham diagram , but i am still not able to make a connection , So what makes exaclty the carbon a good reducing agent ? |
why does FeCl3 have such a specific smell? |
How to calculate it? I know that it depends on the coordination compound and the number of electrons present in t2g and eg orbitals and the final answer is expressed in terms of crystal field splitting parameter. But, how to know how many electrons are there in t2g and eg orbitals?
I think rather than a broad answer... |
>Step 1: Look up [Nickel Carbonyl](http://en.wikipedia.org/wiki/Nickel_carbonyl) and find out what geometry it has.
We need the geometry to know how the $d$ orbitals will split in the ligand field. The geometry can also be predicted: late transition metals with strong field ligands tend to be tetrahedral.
 is a special kind of [phase diagram](http://en.wikipedia.org/wiki/Phase_diagram). As in a phase diagram, the lines of all kinds represent phase boundaries. Each line represents the conditions in which two phases are in dynamic equilibrium. Without info... |
The only clue I have been able to find is a one-off sentence in the [Wikipedia article][1] for $\ce{FeCl3}$, for which no reference is given:
Iron(III) chloride undergoes hydrolysis to give an acidic solution.
If so, then the reactions are probably those along the conversion of $\ce{FeCl3}$ to $\ce{Fe2O3}$, p... |
[This site][1] writes to say
> It turned out that Upsalite had the highest surface area measured for an alkali earth metal carbonate; 800 square meters per gram.
Assuming that a sphere may enclose the maximum volume for a given surface area, the radius for a sphere enclosed by 800 sq.m is 7.9788 m. It's correspo... |
How much water vapour can a gram of Uppsalite absorb at NTP? |
The only clue I have been able to find is a one-off sentence in the [Wikipedia article][1] for $\ce{FeCl3}$, for which no reference is given:
Iron(III) chloride undergoes hydrolysis to give an acidic solution.
If so, then the reactions are probably those along the conversion of $\ce{FeCl3}$ to $\ce{Fe2O3}$, p... |
One fallacy in your question is assuming that the particles 1) are spherical and 2) only accessible on the outside. The press release linked says that this material is [nanoporous](http://en.wikipedia.org/wiki/Nanoporous) - the particles are perforated by pores `all having a diameter smaller than 10 nano meters`. The e... |
LCs materials are dielectric. But they are not perfect insulators and have some non-zero conductivity, allowing a leakage current to flow, slowly discharging the capacitor.
Infact a liquid crystal cell can be modeled electrically as this:
Rl
_____WWW_____
| ... |
LCs materials are dielectric. But they are not perfect insulators and have some non-zero conductivity, allowing a leakage current to flow, slowly discharging the capacitor.
`This is caused by mobile ions in the liquid crystal and inside the polyimide layer [2]`.
Infact a liquid crystal cell can be modeled electricall... |
[This site][1] writes to say
> It turned out that Upsalite had the highest surface area measured for an alkali earth metal carbonate; 800 square meters per gram.
Assuming that a sphere may enclose the maximum volume for a given surface area, the radius for a sphere enclosed by 800 sq.m is 7.9788 m. It's correspo... |
In any spontaneous process entropy increases.In biological systems disordered elements are converted into highly ordered tissues etc(-ve entropy change) which make up living organisms. But, it requires energy from the sun(ultimately). So,does that mean all processes that consume energy from outside result in negative e... |
Does all processes that consume energy from outside result in negative entropy change? |
I have a very basic question concerning solvation. If a solid (solute) was dissolved in a liquid (solvent), is the solute still in the solid state? or does it convert into another state of matter when this happens? |
> does that mean all processes that consume energy from outside result in negative entropy change?
No. When you heat a solid, it increases its entropy.
> endothermic reactions causing the entropy to decrease?
Endothermic reactions which cause entropy to decrease have both ∆H positive and ∆S negative, so they w... |
**Entropy increases in a spontaneous evolution of an isolated system… other than that, there is no general law on the evolution of entropy.**
---
> does that mean all processes that consume energy from outside result in negative entropy change?
No. When you heat a solid, it increases its entropy.
> endother... |
why sometimes hot concentrated sulfuric acid is used to react with metals instead of conc. sulfuric acid which is at room temperature?
Well conc. sulfuric acid has quite strong oxidizing properties.Still some metals which are below the hydrogen in electrochemical series does not react with con sulfuric acid which i... |
Why hot conc.sulfuric acid is better than cold one? |
Why is hot concentrated sulfuric acid sometimes used to react with metals instead of concentrated sulfuric acid which is at room temperature?
I have ascertained that concentrated sulfuric acid has quite strong oxidizing properties. Still, some metals which are below the hydrogen in electrochemical series do not rea... |
Why is hot concentrated sulfuric acid preferable to cold? |
why sometimes hot concentrated sulfuric acid is used to react with metals instead of conc. sulfuric acid which is at room temperature?
Well conc. sulfuric acid has quite strong oxidizing properties.Still some metals which are below the hydrogen in electrochemical series does not react with con sulfuric acid which i... |
Why hot conc.sulfuric acid is better than cold one? |
Why is hot concentrated sulfuric acid sometimes used to react with metals instead of concentrated sulfuric acid which is at room temperature?
I have ascertained that concentrated sulfuric acid has quite strong oxidizing properties. Still, some metals which are below the hydrogen in electrochemical series do not rea... |
Why is hot concentrated sulfuric acid preferable to cold? |
Recently, We covered Mettallic Bonding in Chemistry, and Frankly, I understood Little.
I understand that:
- Metals Bond to Each other Via Metallic Bonding
- Electricity can flow via Free or Delocalized Electrons
But, I do not understand why the metal atoms turn into ions and delocalize the electrons,... |
Why are there Free Electrons In A Metal? |
Recently, we covered metallic bonding in chemistry, and frankly, I understood little.
I understand that:
- Metals bond to each other via metallic bonding
- Electricity can flow via free or delocalized electrons
But, I do not understand why the metal atoms turn into ions and delocalize the electrons... |
Why are there free electrons in a metal? |
Hey this is a fairly naive question but I really hope someone on here can answer.
I want to change CO2 coming out of the tailpipe of a car to some composition that is considerably less harmful to the environment like a filter of some sort.
What are some ways that this is possible?
CO2 to carbon and oxygen?
... |
How to change co2 to a less polluting gas? |
Alcohol can undergo nucleophilic substitution with $\ce{PCl5, POCl3, HCl}$. Halogenoalkanes can undergo nucleophilic substitution with $\ce{NH3}$ and the $\ce{C-O}$ (in alcohol) and $\ce{C-Cl}$ (in chloroalkanes) bond energies are comparable. Why doesn't alcohol undergo nucleophilic substitution with $\ce{NH3}$? |
Why doesn't alcohol undergo nucleophilic substitution with ammonia? |
This is a fairly naive question but I really hope someone on here can answer.
I want to change $\ce{CO2}$ coming out of the tailpipe of a car to some other compound that is considerably less harmful to the environment with a filter of some sort.
What are some ways that this is possible?
$\ce{CO2}$ to carbon a... |
How to change $\ce{CO2}$ to a less polluting gas? |
I want to change $\ce{CO2}$ coming out of the tailpipe of a car to some other compound that is considerably less harmful to the environment with a filter of some sort.
What are some ways that this is possible?
$\ce{CO2}$ to carbon and oxygen?
|
How to change CO2 to a less polluting gas? |
I recently freezed a huge bunch of apple slices, and thawed them again a few days later. After thawing, I noticed a few things compared to a batch that I had put in the fridge (no freezing)
* The apples turned brown far quicker
* After pureeing, they tasted sweeter
I know that slow freezingg can destroy cell wal... |
Can freezing break up sugar polymers? |
Alcohol can undergo nucleophilic substitution with $\ce{PCl5, POCl3, HCl}$. Halogenoalkanes can undergo nucleophilic substitution with $\ce{NH3}$. Besides, the $\ce{C-O}$ (in alcohol) and $\ce{C-Cl}$ (in chloroalkanes) bond energies are comparable. Why doesn't alcohol undergo nucleophilic substitution with $\ce{NH3}$? |
I couldn't find this in any textbooks, so I guess I will ask this here. What is the state of HX when reacting with alcohol (nucleophilic substitution) and alkenes (electrophilic addition) respectively? If possible, can you explain why they have the particular state? For electrophilic substitution of benzene with bromin... |
What are the states of HX when reacting with alcohol and alkenes respectively, and Br2 when reacting with benzene? |
I couldn't find this in any textbooks, so I guess I will ask this here. What is the physical state of HX when reacting with alcohol (nucleophilic substitution) and alkenes (electrophilic addition) respectively? (e.g. aqueous, liquid, solid) If possible, can you explain why they have the particular state? For electrophi... |
According to my teacher, Na in ethanol reduce carbonyl compounds to alcohols. However, I can't see where the hydrogen needed for reduction comes from. How does the reduction take place? |
How does Na in ethanol reduce carbonyl compounds? |
I understand that deflagration is slower and smoother than a detonation , but can't a deflagration be used to initiate detonations of other explosive agents ? |
As the heading above clearly mentions why are they ortho para directing?
Halogens bonded to benzene ring has three lone pairs. These three electron pairs can cause resonance in benzene ring. But, halogens are also highly electronegative and us hey have strong -I effect. So, they are deactivating groups. But, why are... |
Why are halogens ortho para directing even though deactivating? |
Every one have observed that when we pour cool drink or cool water into a transparent glass(or simply glass),some droplets accumulate on the outside part.**Did the droplets come pass through the glass??** If what I said make sense,how can this observation be explained.
![enter image description here][1]
[1]: ... |
Every one have observed that when we pour cool water into a transparent glass(or simply glass),some droplets accumulate on the outside part.**Did the droplets come pass through the glass??** If what I said make sense,how can this observation be explained.
![enter image description here][1]
[1]: https://i.stac... |
According to my teacher, Na in ethanol reduce carbonyl compounds (e.g. aldehydes and ketones) to alcohols. However, I can't see where the hydrogen needed for reduction comes from. How does the reduction take place? (or is my teacher wrong?) |
Both are m-directors, and Electron Withdrawing groups, but which one is more reactive? At first sight, one might think clearly $N(R)_3$ is more reactive, but when you factor in that $R$ is actually an o,p-director, hence activator, then I think $N(R)_3$ is indeed stronger than $NH_3$. I can't seem to find any verificat... |
Is the reactivity of Benzene with $N(R)_3$ group greater than its reactivity with $NH_3$? |
$$molarity = \frac{no\: of\: moles \: of \:solute }{no \: of \: liters\: of \: solution}$$ and no of moles is based on quantity(if weight will be greater no of moles will be greater), so how it is intensive property , it should be extensive property. Please explain?
|
Is the reactivity of Benzene with an $N(R)_3$ group greater than its reactivity with an $NH_3$ group? |
Concentration is an [intensive property](http://en.wikipedia.org/wiki/Intensive_property#Intensive_properties). The value of the property does not change with scale. Let me give you an example:
>Let us say you had a homogenous mixture (solution) of sodium carbonate in water prepared from 112 g of sodium carbonate d... |
Consider the following picture:
![enter image description here][1]
[1]: https://i.stack.imgur.com/1Dw6y.jpg
Break the ice block shown in the picture into two equal halves.Now I hope you would be able to answer the following questions:
1.What are the physical properties of ice block which got halved?
... |
What does this /2 in the structure of calcium benzoate mean? |
Is there a diagram/flow chart available that shows which atoms fused together to make each of the elements? I can find examples for some elements, but nothing which shows all the combinations of atoms which make up each of the naturally occurring elements. |
Which atoms form which elements? |
Both are m-directors, and Electron Withdrawing groups, but which one is more reactive? At first sight, one might think clearly $\ce{-N(R)_3^+}$ is more reactive, but when you factor in that $\ce R$ is actually an o,p-director, hence activator, then I think $\ce{-N(R)_3^+}$ is indeed stronger than $\ce{ NH_3^+}$. I can'... |
Is the reactivity of Benzene with an $-N(R)_3^+$ group greater than its reactivity with an $-NH_3^+$ group? |
>Step 1: Look up [Nickel Carbonyl](http://en.wikipedia.org/wiki/Nickel_carbonyl) and find out what geometry it has.
We need the geometry to know how the $d$ orbitals will split in the ligand field. The geometry can also be predicted: late transition metals with strong field ligands tend to be tetrahedral.
![nic... |
Why in the photochemical substitution of a ligand in a carbonyls complex is required a water-cooled lamp jacket to separate the solution and the mercury vapour lamp? It's shown in Figure 22.16 of Atkins' Inorganic Chemistry.
Thank you |
Photochemical ligand substitution of metal carbonyls - role of water cooled lamp-jacket? |
I've taught in my class that if a molecule posses high degree of symmetry it's stability will be more,in other words symmetry and stability are directly proportional. Is this statement correct? And if this is correct than why John taller distortion stabilizes a molecule when it's symmetry gets low eventually because of... |
I've taught in my class that if a molecule posses high degree of symmetry it's stability will be more,in other words symmetry and stability are directly proportional. Is this statement correct? And if this is correct than why Jahn teller distortion stabilizes a molecule when it's symmetry gets low eventually because of... |
Is there a database or a website with a list of oil : water partition coefficients of substances ?
I actually want the oil:water partition coefficients of :
cholesterol, starch , methyl citrate , citric acid , iso- citrate , methyl urea , carotene
Thanks |
I am interested in Non-Stoichiometry and how it relates to crystal structures; In particular I wish to learn about surfaces of metal oxides. I am aware that point defects in such crystals are a result of an entropy driven reactions. So my question is this:
Are there any good introductory resources on this subject? I... |
How do point defects in a crystal relate to Entropy? |
Why, in the photochemical substitution of a ligand in a carbonyl complex, is a water-cooled lamp jacket required to separate the solution and the mercury vapour lamp? It's shown in Figure 22.16 of Atkins' Inorganic Chemistry.
Thank you |
How is a reduction in the number of molecules associated with a decrease in Entropy? For example, stoichiometric equations like $H_2 + O \implies H_2O$ are enthalpy driven if I am correct. But it also implies that entropy is decreasing because the system is becoming "more orderly." Is this intuition correct? |
How is a reduction in the number of molecules associated with a decrease in Entropy? |
How is a reduction in the number of molecules associated with a decrease in Entropy? For example, stoichiometric equations like $\ce{H2 + O -> H2O}$ are enthalpy driven if I am correct. But it also implies that entropy is decreasing because the system is becoming "more orderly." Is this intuition correct? |
Why, in the photochemical substitution of a ligand in a carbonyl complex, is a water-cooled lamp jacket required to separate the solution and the mercury vapour lamp? It's shown in Figure 22.16 of Atkins' Inorganic Chemistry. |
Interpreting [entropy][1] as "disorder", which comes from thermodynamics applications, is only one way to interpret entropy. Entropy can also be described [according to statistical mechanics][2] as the statistical distribution of possible degenerate microstates:
$$S=k_B \ln\Omega$$
where $k_B$ is [Boltzman's con... |
Two places where you can find predicted values of LogP (the oil:water partitioning coefficient) are [chemicalize.org](www.chemicalize.org) and [Wolfram Alpha](www.wolframalpha.org). Both provide a predicted value for most of the compounds you are interested in (chemicalize provides a complete set, assuming you mean be... |
Chemical nomenclature seems to be the way chemistry "talks", allied with the mathemathics. But where to start?... and what reasons and theories are behind? Some "names" come from *latin*... I know there are rules IUPAC etc, but it is so demanding and exaustive to learn all that rules at once, for organic and inorganic ... |
How do I start studying chemical nomenclature? |
Aren't alpha halo carbonyl compounds extremely fast and reactive via sn2( the fastest i guess)? If it is so, why isn't the major product in favorskii rearrangement a alpha hydroxy carbonyl compound? And if the alpha carbon(to which the halide is attached) is tertiary, there should be a high chance of an elimination pro... |
Aren't alpha halo carbonyl compounds extremely fast and reactive via $S_N2$ (the fastest i guess)? If this is so, why isn't the major product in the Favorskii rearrangement an alpha hydroxy carbonyl compound?
And if the alpha carbon(to which the halide is attached) is tertiary, there should be a high chance of an e... |
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