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Having three σ bonds in a similar manner to $\ce{CH3^·}$ free radical, $\ce{CF3^·}$ should also have $\mathrm{sp^2}$ hybridisation. However, if we look at its shape, it is pyramidal and not planar like $\ce{CH3^·}$ free radical (which is $\mathrm{sp^2}$-hybridised), which signifies that $\ce{CF3^·}$ should have $\mathr... |
What is the hybridisation of CF₃· free radical? |
What is the hybridisation of trifluoromethyl free radical? |
The solubility of an alcohol in a non-polar solvent (like hexane) increases with size of the alcohol, as the non-polar chain increases. However, as the chain keeps increasing, will the solubility eventually start to drop because the molecule becomes too large? |
When labeling the energies of molecular orbitals, often some anti-bonding MOs are shown with a positive energy. For example, MolCalc has the following energies for methane (the anti-bonding MO #8 at +19.47 eV depicted on the right):
[![enter image description here][1]][1]
I'm trying to understand what these numbe... |
For molecular orbitals, how is an energy of zero set or defined? |
This is the article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5611670/
I'm not a Chemist, so I can't understand the article very well.
The conclusion states that the molecules tested should not be called "piezolytes". Is this a nomenclature issue only? My only question is: does the presence of such molecules in... |
Can someone explain the article below? |
When labeling the energies of molecular orbitals, often some anti-bonding MOs are shown with a positive energy. For example, MolCalc has the following energies for methane (the anti-bonding MO #8 at +19.47 eV depicted on the right):
[![enter image description here][1]][1]
I'm trying to understand what these numbe... |
Gefitinib has been shown to be an effective tyrosine kinase inhibitor in a fraction (~$10$%) of non-small cell lung cancer patients.
These patients are characterized as having a mutation (usually a deletion or missense) in the _EGFR_ gene effecting the ATP-binding site.
I have two questions:
-- How does gefiti... |
I've been curious about this 3D representation of the periodic table "Mendeleev's Flower" and was trying to study it, wondering if it reveals any regularities that are not obvious from classic periodic table.
[![Mendeleev's Flower][1]][1]
But since it's hard to look at a 3D table on a flat computer screen, I foun... |
Why aren't Boron and Aluminium assigned to group 3 of periodic table? What determines the group? |
I've been curious about this 3D representation of the periodic table "Mendeleev's Flower" and was trying to study it, wondering if it reveals any regularities that are not obvious from classic periodic table.
[![Mendeleev's Flower][1]][1]
But since it's hard to look at a 3D table on a flat computer screen, I foun... |
This is my first question, sorry if I don't know how to write a good question.
why is O3 shaped like this?:[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/dzCL5.png
and not shaped like each Oxygen molecule is connected to two other molecules?
(i did not find an image for that)
|
In computational chemistry, it is extremely common to freeze the core electrons after an initial Hartree-Fock calculation, meaning that the core electrons are left out of any treatment of the electron correlation. Which orbitals are considered core depends on the atom, but for the second row, it usually just means the ... |
Non-Trivial cases where the frozen core approximation is bad? |
I've been curious about this 3D representation of the periodic table "Mendeleev's Flower" and was trying to study it, wondering if it reveals any regularities that are not obvious from classic periodic table.
[![Mendeleev's Flower][1]][1]
But since it's hard to look at a 3D table on a flat computer screen, I foun... |
Gefitinib has been shown to be an effective tyrosine kinase inhibitor in a fraction (~$10$%) of non-small cell lung cancer patients.
These patients are characterized as having a mutation (usually a deletion or missense) in the _EGFR_ gene affecting the ATP-binding site.
I have two questions:
-- How does gefiti... |
>How does gefitinib impede the proliferation and apoptosis pathway? Does it in effect "ace out" the binding of EGF? If this is correct, how does it accomplish that? If not, I would appreciate a brief explanation as to what the successful mechanism is.
[![enter image description here][1]][1]
No, EGF binds on the ext... |
Summarizing from the excellent comments:
> Isn't the order of the reaction supposed to be the sum of powers of the concentration of the reactants?
Yes, that is how you get the overall order of reaction. If you compare the rate with a given set of concentrations to the rate with all concentrations doubled, the rat... |
Do molecules with bridges through rings (in a manner illustrated by this) exist?
[![example diagram][1]][1]
I sometimes get results like this when doing Energy Minimization on molview.org. For example: [![molview.org Jmol result][2]][2]
Is this actually a thing?
EDIT: As a slightly more realistic example, c... |
Non-trivial cases where the frozen core approximation is bad? |
I understand that energy is a fairly arbitrary concept, and that it completely depends on your definition of energy. So far in my class, we have discussed:
- Entropy, $S$ (not really energy, but it seems to be closely related);
- Total internal energy, $U$, for which it is impossible to find an absolute value for;
... |
Why are there so many different formulations for energy? When do I use each one? |
Do molecules with bridges through rings (in a manner illustrated by this) exist?
[![example diagram][11]][1]
I sometimes get results like this when doing Energy Minimization on molview.org. For example:
[![molview.org Jmol result][12]][2]
Is this actually a thing?
EDIT: As a slightly more realistic exam... |
Why does attaching an -NO2 group at the ortho position of benzoic acid cause -COOH to become perpendicular to the plane of the benzene ring? Why doesn't the nitro group get pushed out while -COOH stays on the plane?
Also, in the case of two -NO2 groups attached on the ortho and meta positions of benzoic acid, both... |
Why does attaching an $\ce{-NO2}$ group at the *ortho* position of benzoic acid cause $\ce{-COOH}$ to become perpendicular to the plane of the benzene ring? Why doesn't the nitro group get pushed out while $\ce{-COOH}$ stays on the plane?
Also, in the case of two $\ce{-NO2}$ groups attached on the *ortho* and *meta... |
<b>Is it possible to selectively halogenate a certain position on an alkane chain, and also get a good yield?</b>
I understand that to form such haloalkanes, taking a different substrate other than alkane (like a substituted alkane with the substituent attached at that position) would be a good choice, but is there a ... |
Is the mixture of 97% isopropyl alcohol and 1% of sodium hypochlorite safe?
Do they react together and form any compounds ?
Does this mixture present more danger to humans and animals than its ingredients separately ? |
Safety of IPA and sodium hypochlorite mixture? |
Is the mixture of 97% isopropyl alcohol and 0.5% of sodium hypochlorite safe?
Do they react together and form any compounds ?
Does this mixture present more danger to humans and animals than its ingredients separately ? |
Could anyone recommend me a good proven free-radical photoinitiator available commercially suitable for (meth)acrylate-based UV-light photo-polymerizations ocurring in water phase, preferably with high water solubility and moderate-to-high quantum yield of photoinitiation? Commercial suppliers would also be highly appr... |
Water-Soluble Photoinitiators for Free-Radical Photopolymerizations? |
What purpose does water serve in rust formation?"
First, one should ask what is the temperature of the water and the source of the water? Cold from a faucet implying possible oxygen content along with say free $\ce{Cl2}$ or even $\ce{NH2Cl}$, or natural aerated waters containing transition metal salts (including t... |
I have been studying chemistry for a short time and studied the nomenclature of inorganic compounds. I got to naming acids, and got really confused with several things, including the definition of oxidation number. Let me explain myself:
I started studying using the book Chemical Principles: The Quest for Insight ... |
So I'm trying to figure out how to melt florescent acrylic without it changing. What it's doing after it's melted is florescing a sort of opaque white instead of it's original color. Could someone point me in a direction to look for answers as to what's happening, why it's happening, and how to avoid it?
Thanks a hea... |
So I'm trying to figure out how to melt florescent acrylic without it changing. What it's doing after it's melted, under UV it's florescing a sort of opaque white instead of it's original color. Keep in mind that normally florescent acrylics look almost the same under UV as they do in daylight, just a little more brill... |
Is HF the least acidic hydrogen halide? |
As part of my homework, I had to plan the synthesis of labetalol, a blood pressure drug, from its component parts. One of the steps involved was the following S<sub>N</sub>2 reaction:
[![enter image description here][1]][1]
The solutions manual just shows the two being added together, but my mind harkened back to... |
Can triethylamine/pyridine be used in the synthesis of Labetalol? |
This is one of those heterogenous reactions occurring on a surface which are mechanistically messy. As expected for a reaction that occurs on the surface of a reagent, factors such as surface area and reagent preparation (freshness, surface contamination) are significant variables. A free radical mechanism is general... |
I want to keep a medical-grade 3% H2O2 solution in a glass vial as the container for medicinal applications. It was claimed that inside of the vial should be covered with a thin layer of silicone to prevent H2O2 decomposition. Is there any need for this? |
Like solid $PCl_5$, does solid $NH_3$ exist as $NH_4 ^{+} NH_2 ^{-}$? (i.e ammonium amide) |
I've always been told that carbon links with four hydrogens and nitrogen with three hydrogens like in benzene and hexazine. What's the name of this bonding and how do you come up with the number? Sorry if this is a very basic question; I'm trying to refine my chemistry while learning the terminology in English. |
So I'm trying to figure out how to melt fluorescent poly without it changing. What it's doing after it's melted, under UV it's fluorescing a sort of opaque white instead of it's original color. Keep in mind that normally fluorescent acrylics look almost the same under UV as they do in daylight, just a little more brill... |
I've always been told that carbon bonds with four hydrogens and that nitrogen bonds with three hydrogens, like in benzene and hexazine, respectively.
What's the name of this type of bonding and how does one come up with the number? |
How do I find out the number of bonds an atom must link to? |
How does one determine whether a chemical requires hazardous waste disposal? |
$\ce{N2H4}$ has a boiling point of $114^o$ C, which is higher than the melting point of water. Why is this so?
Both $\ce{N2H4}$ and $\ce{H2O}$ have $2$ lone pairs, so the number of hydrogen bonds per molecule seems to be the same. Also, the $\ce{O...H}$ hydrogen bond (21 kJ/mol) is stronger than the $\ce{N...H}$ hyd... |
Why does N2H4 have a higher boiling point than H2O? |
First of all as @chipbuster says $\ce{HF}$ in diluted solutions in water is nearly completely dissociated and therefore **shouldn't be called weak**. [Wikipedia][1] describes this nicely and cites [several][2] [sources][3] for this claim.
It was rather difficult to prove (spectroscopic methods were used), because hy... |
<br>
I am wondering is there any open source software that predict NMR spectra by giving the chemical shift?<br>
Something like Spinach library http://spindynamics.org/group/?page_id=12 (Matlab is not free, so...).<br>
Thanks! |
I am wondering is there any open source software that predict NMR spectra by giving the chemical shift?
Something like Spinach library http://spindynamics.org/group/?page_id=12 (Matlab is not free, so...). |
So I'm trying to figure out how to melt fluorescent poly without it changing. What it's doing after it's melted, under UV it's fluorescing a sort of opaque white instead of it's original color. Keep in mind that normally fluorescent acrylics look almost the same under UV as they do in daylight, just a little more brill... |
The problem with computational chemistry software (ORCA etc.), as described in NotEvans' answer, is that they only spit out a list of chemical shifts and coupling constants. For example, this is part of a typical ORCA output:
--------------
Nucleus 34H :
--------------
[...]
T... |
The problem with computational chemistry software (ORCA, GAMESS etc.), as described in NotEvans' answer and in various comments, is that they only spit out a list of chemical shifts and coupling constants. For example, this is part of a typical ORCA output:
--------------
Nucleus 34H :
------------... |
The problem with computational chemistry software (ORCA, GAMESS etc.), as described in NotEvans' answer and in various comments, is that they only spit out a list of chemical shifts and coupling constants. For example, this is part of a typical ORCA output:
--------------
Nucleus 34H :
------------... |
The problem with computational chemistry software (ORCA, GAMESS etc.), as described in NotEvans' answer and in various comments, is that they only spit out a list of chemical shifts and coupling constants. For example, this is part of a typical ORCA output:
--------------
Nucleus 34H :
------------... |
Like solid $\ce{PCl5}$, does solid $\ce{NH3}$ exist as $\ce{[NH4+][NH2-]}$ (i.e. ammonium amide)? |
Is there a crystal structure of ammonia in ionic form? |
$\ce{N2H4}$ has a boiling point of 114 °C, which is higher than the melting point of water. Why is this so?
Both $\ce{N2H4}$ and $\ce{H2O}$ have two lone pairs, so the number of hydrogen bonds per molecule seems to be the same. Also, the $\ce{O...H}$ hydrogen bond (21 kJ/mol) is stronger than the $\ce{N...H}$ hydrog... |
Why does hydrazine have a higher boiling point than water? |
I am a high school student and I don't know a whole lot about molecular simulation. I wish to view different conformers of cyclohexane and the changes that occur when substituents are attached (for example $cis$-1,4-di-tertbutylcyclohexane attains a twist boat shape) through molecular simulation.
The only easy-to-use... |
I am a high school student and I don't know a whole lot about molecular simulation. I wish to view different conformers of cyclohexane and the changes that occur when substituents are attached (for example *cis*-1,4-di-tertbutylcyclohexane attains a twist boat shape) through molecular simulation.
The only easy-to-u... |
$\ce{N2H4}$ has a boiling point of 114 °C, which is higher than the boiling point of water. Why is this so?
Both $\ce{N2H4}$ and $\ce{H2O}$ have two lone pairs, so the number of hydrogen bonds per molecule seems to be the same. Also, the $\ce{O...H}$ hydrogen bond (21 kJ/mol) is stronger than the $\ce{N...H}$ hydrog... |
A well known strategy for paper maintenance is to store it in a antacid enviroment
(special boxes, envelopes etc)
There are also special preservation acid free papers and archival material (envelopes etc) "buffered" with a base material
(usually CaCO3) to help keep the pH of the paper to be preserved in the >7 pH z... |
I know that most of the double displacement reactions form some kind of precipitates as their products. But do all of the double displacement reactions form precipitates? I have searched on this site as well as on Google, I've found answers, but they are not clarifying my doubts. Maybe I need a simpler explanation.
... |
Do all double displacement reactions lead to precipitates? |
A well known strategy for paper maintenance is to store it in a antacid enviroment
(special boxes, envelopes etc)
There are also special preservation acid free papers and archival material (envelopes etc) "buffered" with a base material
(usually CaCO3) to help keep the pH of the paper to be preserved in the >7 pH z... |
I would like to ask if anyone has any information (schematic diagram)of vector correlations for CO2 molecule. (Is it bending in the excited state with μ in plane? How CO fragment can be ejected after the break?)
Thank you in advance |
> Which of the following compounds give same S<sub>N</sub>1 and S<sub>N</sub>2 product?
> [![a: 4‐chlorocyclohex‐1‐ene; b: 5‐(chloromethyl)cyclohexa‐1,3‐diene; c: 3‐chlorocyclohex‐1‐ene; d: 1‐chloro‐2‐methylcyclohexane][1]][1]
I think (**b**) should be the answer, but the given answer is (**c**). I think so as it... |
A well known strategy for paper maintenance is to store it in a antacid enviroment
(special boxes, envelopes etc.).
There are also special preservation acid-free papers and archival material (envelopes etc.) "buffered" with a base material (usually $\ce{CaCO3})$ to help keep the pH of the paper to be preserved in t... |
Molecular orbital theory is successful in calculating the structure of molecules (minimizing the total energy with respect to atomic positions). The solutions of an MO calculation are useful in deriving molecular properties such as dipole moment or vibration frequencies. These do not rely on energies of electrons in di... |
What can we learn from the energies of molecular orbitals? |
Molecular orbital theory is successful in calculating the structure of molecules (minimizing the total energy with respect to atomic positions). The solutions of an MO calculation are useful in deriving molecular properties such as dipole moment or vibration frequencies. These do not rely on energies of electrons in di... |
>A metal $\ce{Q}$ forms a carbonate and a nitrate. The molecular formula of the carbonate of $\ce{Q}$ is $\ce{QCO3}$. What is the molecular formula of the nitrate of $\ce{Q}$?
The answer says it is $\ce{Q(NO2)3}$ which I think is incorrect; I think the answer should be $\ce{Q(NO3)2}$. Am I right? |
What is the molecular formula of the nitrate of a metal Q that forms a carbonate of the form QCO3? |
So, metal oxides are generally basic, right? But in higher oxidation states their covalent character is predominant. For example in
Mn2O7 the Mn - O bond is covalent. Why is that? |
I'll try to explain the source of my confusion as clear as possible:
(*) The methyl protons in toluene are decoupled because the C-C bond between the methyl group and benzene allows very fast rotation. Hence, on average, these protons will see the same environment.
It is said that the time scale for the rotation ... |
What exchange timescales are needed to cause decoupling in NMR? |
What does it mean to accept or donate a proton? |
I'll try to explain the source of my confusion as clear as possible:
(*) The methyl protons in toluene are decoupled because the C-C bond between the methyl group and benzene allows very fast rotation. Hence, on average, these protons will see the same environment.
It is said that the time scale for the rotation ... |
To answer your question, yes on calcium carbonate layer but its surface action is just limited to pH control. Also, consider baking soda, which may add more than surface pH control due to its solubility.
Some other ideas to address other concerns as well, which may be present in more tropical locales, including thre... |
To answer your question, yes on calcium carbonate layer but its surface action is just limited to pH control. Also, consider baking soda, which may add more than surface pH control due to its solubility.
Some other ideas to address other concerns as well, which may be present in more tropical locales, including thre... |
To answer your question, yes on calcium carbonate layer but its surface action is just limited to pH control. Also, consider baking soda, which may add more than surface pH control due to its solubility.
Some other ideas to address other concerns as well, which may be present in more tropical locales, including thre... |
It is generally true that the electron affinity becomes less exothermic down a group, because of the increase in atomic radius.
There is a well-known exception that the electron affinity of Cl is more exothermic than that of F, because fluorine has a high electron density; adding electrons would be unfavorable becau... |
Why does the electron affinity increase become more exothermic down group 2 and group 5? |
$$\ce{NH3 + HOCl <=> NH2Cl + H2O}$$
How do I figure out what is the oxidizing agent and the reducing agent?
I know that the oxidation state of $\ce{N}$ in $\ce{NH3}$ is $-3$, but I'm not sure how to proceed with the rest.
Oxidation numbers for $\ce{NH2Cl}$:
- $\ce{N} =~ –1$
- $\ce{H} =~ +1$
- $\ce{Cl} ... |
How do I figure out what is the oxidizing agent and the reducing agent in the following reaction:
$$\ce{\overset{-3}{N}\overset{+1}{H}_3 + \overset{+1}{H}\overset{-2}{O}\overset{+1}{Cl} <=> \overset{-1}{N}\overset{+1}{H}_2\overset{-1}{Cl} + H2O}~?$$
I assigned known oxidation numbers for the elements, but I'm not... |
How to determine oxidising and reducing agents in the reaction between ammonia and hypochlorous acid? |
In (I think all of the) molecular orbital (MO) diagrams I have seen, I have observed that the number of antibonding molecular orbitals is the same as the number of bonding molecular orbitals.
Here are some for example:
[![enter image description here][1]][1]
[![enter image description here][2]][2]
I know tha... |
In (I think all) of the molecular orbital (MO) diagrams I have seen, I have observed that the number of antibonding molecular orbitals is the same as the number of bonding molecular orbitals.
Here are some for example:
[![enter image description here][1]][1]
[![enter image description here][2]][2]
I know tha... |
Is magnesium sulfate an acidic, neutral, or basic salt? Which color will it show in ph indicator?
In my opinion it needs to be slightly acidic hence turns indicator yellow
|
Is magnesium sulfate an acidic, neutral, or basic salt? Which color will it show with the universal ph indicator?
In my opinion it needs to be slightly acidic hence turns indicator yellow
|
I read about frontier orbitals, namely **HOMO, LUMO**. But what's exactly **HOMO/LUMO**? I know **HOMO** stands for highest occupied molecular orbital and LUMO stands for lowest unoccupied molecular orbital.
But I am not getting which orbital is to be tagged as **HOMO**, and which as **LUMO**. Consider the example ... |
What exactly are frontier orbitals? |
I read about frontier orbitals, namely **HOMO, LUMO**. But what's exactly **HOMO/LUMO**? I know **HOMO** stands for highest occupied molecular orbital and LUMO stands for lowest unoccupied molecular orbital.
But I am not getting which orbital is to be tagged as **HOMO**, and which as **LUMO**. Consider the example ... |
I read about frontier orbitals, namely **HOMO, LUMO**. But what's exactly **HOMO/LUMO**? I know **HOMO** stands for highest occupied molecular orbital and LUMO stands for lowest unoccupied molecular orbital.
But I am not getting which orbital is to be tagged as **HOMO**, and which as **LUMO**. Consider the example ... |
On a recent quiz, we were asked the following question:
<br /><br />
**A(aq)+B(aq)=C(aq)<br /><br />
At 298 K, the equilibrium amounts of each of the component are as follows: [A] = 0.125 M, [B] = 0.400 M, [C] = 1.200 M. At 298 K, the system is perturbed by increasing the concentration of B by adding X amount. Whe... |
On a recent quiz, we were asked the following question:
<br /><br />
>$\ce{A(aq) + B(aq) <=> C(aq)}$<br >
>At 298 K, the equilibrium amounts of each of the component are as follows: [A] = 0.125 M, [B] = 0.400 M, [C] = 1.200 M. At 298 K, the system is perturbed by increasing the concentration of B by adding X amo... |
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