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Stevens and Beutel studied the activity of several carbamate anticholinesterases. Among other things, they found that the (4-trimethylammonio)phenyl dimethylcarbamate iodide (The para-analog of neostigmine) is significantly less active than neostigmine (Subcutaneous LD50 in mice of the para-analog was 120 mg/kg compare... |
How do structural differences between neostigmine and TL-599 contribute to differences in toxicity? |
Consider the perturbation treatment of He $1s2s$ excited state configuration. The quantum mechanical Hamiltonian for the He-atom is:
\begin{aligned}
\hat{H} = \sum_{i=1}^2 h_i + \frac 1 {r_{1 2}} \\
h_i = -\tfrac 12 \nabla_i^2 - \frac 1 r_i
\end{aligned}
In the following perturbation treatment, the unperturbed... |
Is the correct zeroth-order wave function ϕ⁽⁰⁾ the eigenfunction of the perturbation Hamiltonian H'? |
The breaking of bonds usually absorbs energy and forming bonds usually releases energy.
Then, why is the dilution of acids and bases exothermic? |
Consider the perturbation treatment of He $1s2s$ excited state configuration. The quantum mechanical Hamiltonian for the He-atom is:
\begin{aligned}
\hat{H} = \sum_{i=1}^2 h_i + \frac 1 {r_{1 2}} \\
h_i = -\tfrac 12 \nabla_i^2 - \frac 1 r_i
\end{aligned}
In the following perturbation treatment, the unperturbed... |
> Which one of the following is NOT a haloalkane?
>
> A) Freon
>
> B) Teflon
>
> C) Iodoform
>
> D) Vinyl chloride
Every compound here seems to me as a haloalkane: Freon, Teflon, iodoform, and vinyl chloride.
P.S.: My text says the answer is vinyl chloride, but how ? |
Consider the perturbation treatment of He $1s2s$ excited state configuration. The quantum mechanical Hamiltonian for the He-atom is:
\begin{aligned}
\hat{H} = \sum_{i=1}^2 h_i + \frac 1 {r_{1 2}} \\
h_i = -\tfrac 12 \nabla_i^2 - \frac 1 r_i
\end{aligned}
In the following perturbation treatment, the unperturbed... |
In the ion-exchange chromatography literature, a term "degree of crosslinking" appears frequently. Ion exchange resins are typically made from divinylbenzene and styrene. One of the stated characteristics is the "degree of crosslink" which is often stated as 5% to 55% crosslink with DVB?
The term degree of crosslin... |
How can 2-Methylcyclopentanone show geometrical isomerism?
(Since a ring and a double bond are in different planes so even after having restricted rotation there will be no change in areal distance) |
Consider the dehydration reaction of the following compounds with $\ce{H2SO4}$:<br>
>(a) Tert-butyl alcohol<br>
>(b) 3-Methylbut-2-en-1-ol<br>
Consider the protonation of the $\ce{OH}$ group followed by the removal of a water molecule. In (a), we get a tertiary carbocation whereas in (b) we get a primary allylic c... |
In the ion-exchange chromatography literature, a term "degree of crosslinking" appears frequently. Ion exchange resins are typically made from divinylbenzene and styrene. One of the stated characteristics is the "degree of crosslink" which is often stated as 5% to 55% crosslink with DVB.
The term degree of crosslink... |
How can 2-methylcyclopentanone show geometrical isomerism?
A ring and a double bond are in different planes, so even after having restricted rotation there will be no change in areal distance. |
Is there geometrical isomerism in case of 2-methylcyclopentanone? |
So I opened up some lantern batteries, and inside there's MnO2 powder, carbon rods, and zinc casings, and other stuff that IDK what it is exactly. I scraped out the MnO2 but I would like elemental manganese from it. How strong a reducing agent do I need? How hot does it need to get? Can I just add charcoal powder and s... |
How to measure chlorine content using ORP sensor? |
If I understand correctly, the fluid in the Hampson-Linde cycle goes through an isenthalpic (basically a free?) expansion. For ideal gases, T would remain the same. But, depending on the substance and the temperature, the fluid may cool down.
My question is: why enthalpic? If the work (of the expanding fluid) could b... |
In my project I need to measure pH, turbidity, and chlorine level of treated drinking water. I found sensors for measuring pH, turbidity, and also chlorine.
The actual problem begins is that the cost of chlorine sensor is too high, so I googled for an alternative solution, which led me to use an oxidation-reduction... |
> Which one of the following is NOT a haloalkane?
>
> A) Freon
> B) Teflon
> C) Iodoform
> D) Vinyl chloride
Every compound here seems to me as a haloalkane: Freon, Teflon, iodoform, and vinyl chloride.
My text says the answer is vinyl chloride, but how? |
I opened up some lantern batteries, and inside there's $\ce{MnO2}$ powder, carbon rods, and zinc casings, and other stuff that I don't know what it is exactly. I scraped out $\ce{MnO2}$-containing powder, but I would like elemental manganese from it.
How can I obtain manganese from manganese dioxide? How strong a re... |
How to refine manganese metal from manganese(IV) oxide found in batteries? |
I was reading about Hansch-Fujita equations from [Hansch-Fujita paramaters][1] and observed that the $π$ values of substituents (analogous to Hammet $σ$ values) change according to the specific environment as depicted in the following table: [![p][2]][2]
I can't understand why is that the case. I mean in Hammet eq... |
Does π values vary in Hansch-Fujita equations for a given substituent? |
Some days ago, I tried for the first time a chromatography machine.
The data I collected are the following:
$$
\begin{array}{lrrr}
\hline
\text{Compound} & t_\mathrm{R}/\pu{min} & w/\pu{min} & N \\
\hline
\text{Benzene} & 2.325 & 0.047 & 39153 \\
\text... |
What's the chemical reaction between coffee and sodium bicarbonate? |
A welder showed me a way of promoting rust on steel by brushing on muriatic acid and then a hydrogen peroxide / water solution. What's going on, chemically speaking?
HCl + H2O2 => Fe2O3 + gas?
|
Research notes in this ACS article [Kinetics of Hydrogen Reduction of Manganese Dioxide](https://pubs.acs.org/doi/10.1021/i260026a023) that even heating $\ce{MnO2}$ in an atmosphere of hydrogen gas only results in $\ce{MnO}$.
The source further notes that very high temperatures (some 1,600 K) are required for any ap... |
A welder showed me a way of promoting rust on steel by brushing on muriatic acid and then a hydrogen peroxide / water solution. What's going on, chemically speaking?
|
The chemistry here can be explained from the associated products of the electrolysis of brine. To quote an [education source](https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/17%3A_Electrochemical_Cells/17.03%3A_Electrolysis_of_Brine):
>Three important chemicals, NaOH, Cl2, ... |
The chemistry here can be explained from the associated products of the electrolysis of brine. To quote an [education source](https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/17%3A_Electrochemical_Cells/17.03%3A_Electrolysis_of_Brine):
>Three important chemicals, NaOH, Cl2, ... |
The rusting of steel may be promoted by brushing with HCl followed by brushing with hydrogen peroxide solution. What is the chemistry involved? |
Assume you have a galvanic (voltaic) cell with E = +2V. If you wanted to reverse the current by inserting a 9V battery, which end of the battery should connect to the cathode of the galvanic cell?
The Kaplan answer key states that the "positive end of the battery should connect to the **cathode**."
Since electron... |
How do you connect a battery to a galvanic cell in order to reverse the flow of electrons? |
The chemistry here can be explained from the associated products of the electrolysis of brine. To quote an [education source](https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/17%3A_Electrochemical_Cells/17.03%3A_Electrolysis_of_Brine):
>Three important chemicals, NaOH, Cl2, ... |
The chemistry here can be explained from the associated products of the electrolysis of brine. To quote an [education source](https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/17%3A_Electrochemical_Cells/17.03%3A_Electrolysis_of_Brine):
>Three important chemicals, NaOH, Cl2, ... |
If you carbonate water, and then expose the resulting soda water to the atmosphere and wait until it goes completely flat, will the (former) soda water end up more acidic in final equilibrium than water that was never carbonated and is also exposed to the atmosphere?
(Assume that both the water that was and was not ... |
Does carbonation permanently increase the acidity of soda water? |
My book states the following:
>Down the group(Group-1), tendency to form complexes decreases due to decrease in charge density$\bigg(\frac{\text{charge}}{\text{radius}}\bigg).$ This results in decrease in ion dipole interaction between metal atom and the approaching ligand.
**My logic-**
There is a sudden avai... |
Usually, when we analyze reactions, we assume that the reaction takes place at constant pressure or at constant volume. But there is no reason to assume this is generally the case, and so my friend posed the following question that has a different condition:
> $n=0.1$ mols of $\ce{SO3}$ are put into a container of v... |
It's in a phase diagram topic. It's about Cu-Sn phase diagram.
[![enter image description here][1]][1]
I find this schematic diagram that describe the following scenarios and identifies the regions and the phases at 40%Sn alloy from 800°C "L → L and γ → L, γ, and ε → L and ε"
confusing to follow.
Does the... |
What does this example mean? Slow cooling of 40% Sn alloy from 800°C to 600°C: L → L and γ → L, γ, and ε → L and ε |
It's in a phase diagram topic. It's about Cu-Sn phase diagram.
[![enter image description here][1]][1]
And it has a question of:
Write the schematic diagram describing the following scenarios and identifies the regions and the phases when Slow cooling of 13.1% Sn alloy from 1000oC to 300oC happens.
I have thi... |
My book states the following:
>Down the group(Group-1), tendency to form complexes decreases due to decrease in charge density$\bigg(\frac{\text{charge}}{\text{radius}}\bigg).$ This results in decrease in ion-dipole interaction between metal atom and the approaching ligand.
**My logic-**
There is a sudden avai... |
Consider the Oxymercuration - Demercuration of the following compound with $\ce{Hg(OAc)2}$ followed by treatment with $\ce{NaBH4}$ in aqueous medium:<br>
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/upjUG.png
Here, if we go according to Markovnikov addition of water to the double bond... |
Consider the Oxymercuration - Demercuration of the following compound with $\ce{Hg(OAc)2}$ followed by treatment with $\ce{NaBH4}$ in basic medium:<br>
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/upjUG.png
Here, if we go according to Markovnikov addition of water to the double bond, ... |
This is an interesting question and environmentally related significant topic.
First, a pertinent related observation on dissolved oxygen content, to quote a [question and its answer](https://support.hach.com/app/answers/answer_view/a_id/1002879/~/how-does-salinity-affect-dissolved-oxygen-solubility%3F-#:~:text=How%... |
In 1812 I found a paper which specifically mentions the evolution of a gas in a situation:
https://www.tandfonline.com/doi/pdf/10.1080/14786441208638245?casa_token=3AxXlRbQG2kAAAAA:4DUMn07xbNth5oeGbxUgTeQMVWsaUDcpHJLwBZfLzdkYcOB7NlW_sv-li5u_TgFauEvdtUEs4rNHJw
And in 1808 I can find a similar reference, except it us... |
Who coined the term "gas evolution reaction"? |
There is no specific term as "gas evolution reaction" in modern chemistry but the word evolve itself conveys this meaning of emission. I am curious as to why you are interested in this terminology? Just for the sake of historical interest, the unabridged Oxford Dictionary (subscription required) shows that the term dat... |
I found a paper from 1812 which specifically mentions the evolution of a gas \[[1](https://doi.org/10.1080/14786441208638245)\].
There is a similar reference from 1808, except it uses the term evolution to speak of green light emitted when a material touches a green wire \[[2](https://doi.org/10.1080/147864408085638... |
> What is the difference between Hexagonal Close Packing (HCP) structures and the hexagonal crystal Bravais lattice?
HCP structures have a lattice that is classified as hexagonal Bravais lattice. There are many other structures that have a hexagonal Bravais lattice but are not HCP structures.
The HCP structure co... |
In the following [table from the CRC Handbook][1], molar conductivities of aqueous electrolytes are given for concentrations from infinite dilution to 0.1 M. However, I am looking for values at 1 M, and I'm having a hard time finding that information. (The following table probably stops at 0.1 M because the Debye-Huc... |
Bonding between main group elements is obviously almost entirely covalent and it is often easy to see these covalent bonds as 2c-2e bonds localised between two atoms. The bonding in borane, boron clusters and hypervalent compounds like SF6 introduce a more delocalised view of covalency as the bonding can be rationalise... |
Usually, when we analyze reactions, we assume that the reaction takes place at constant pressure or at constant volume. But there is no reason to assume this is generally the case, and so my friend posed the following question that has a different condition:
> $n=0.1$ mols of $\ce{SO3}$ are put into a container of v... |
Drierite a brand name of a commonly-used, calcium sulfate-based dessicant in many chemistry labs. The lab I work in has a dessicator box we use to store hygroscopic materials. It isn't a a true dry box, just an air-sealed box with a big tray of dessicant at the bottom. A cheap humidity meter we bought suggests the h... |
Why does my drierite turn bright bright blue, instead of pink? |
So I come from the math community (so please disregard my ignorance on the topic).
If I have a water molecule and write the potential energy surface associated with it, my understanding is that I will find that the atoms configuration minimizes the potential energy function, so it will be a critical point of the pot... |
Does correct bond lengths and angles imply that water is in a potential minimum? |
It's in a phase diagram topic. It's about Cu-Sn phase diagram.
[![enter image description here][1]][1]
And it has a question of:
Write the schematic diagram describing the following scenarios and identifies the regions and the phases when Slow cooling of 13.1% Sn alloy from 1000oC to 300oC happens.
I have thi... |
Is the correct zeroth-order wave function $\phi^{(0)}$ an eigenfunction of the perturbation Hamiltonian $H'$? |
So pretend we have two samples of pure benezene in equilibrium with its vapor. One sample containing 0.5 mol and one containing 1 mol. They're also both at the same temperature. Let's pretend they're both at, say, 298 K (room temperature). Would the two samples have the same vapor pressure? I was thinking since the 1 m... |
What affects the vapor pressure of a pure liquid? |
Interesting question but the sad answer is we will never know the true story. Here is the original text (thanks to Google Books) dated 1863, right from the horse's mouth Adolf von Baeyer.
> *Dieser Gedanke hat mich bei der folgenden Arbeit geeitet (spelling?), und ich habe
> mich zunächst bemüht, die Kenntnis des M... |
As Copper boilers age and develop oxide buildup, does this lessen the copper's antimicrobial abilities in killing bacteria? I was thinking since that coating would be on the copper there would be less contact between it and the water, thus killing less bacteria. |
I am seeking a $\delta ^{13}\mathrm{C}_\text{VPDB}$ database, since I would like to make a figure showing the different isotopic compositions of different materials. I already did some research but I only coudl find figures not the raw data, and extracting the data from figures is tedious and not that accurate. Is ther... |
As copper boilers age and develop oxide buildup, does this lessen the copper's antimicrobial abilities in killing bacteria? I was thinking since that coating would be on the copper, there would be less contact between it and the water, thus killing less bacteria. |
Do antimicrobial abilities of copper boilers decrease over time? |
I am seeking an isotopic composition database for carbon isotopes, since I would like to make a figure showing the different isotopic compositions of different materials. The best woudl be if the values are given as $\delta$ values versus the international VPDB-scale (VPDB=Vienna Pee Dee Belemnite)
I already did some ... |
Question:
Oxalic Acid, H2C2O4 has two pKa values, 1.25 and 4.27. A 0.100 M solution of oxalic acid was titrated with a 0.100 M solution of HaOH. What is the pH at the second equivalence point?
a) 1.23
b) 5.60
c) 8.40
d) 12.52
I tried to make an ICE table with, but since I don't know the amount of... |
L = $6.022*10^{23}$
If I have one atom of oxygen , it has exactly L value.
Now 2 atoms of a oxygen have 2L value.(Note that I mean 2O and not $O_2$here)
Well , if we take a molecule made up of 2atoms or combined i.e ($O_2$It also has L value. How is that possible ?It has bigger size and probably more atoms.
Referen... |
How is this possible in mole concept? |
L = $6.022*10^{23}$
If I have one atom of oxygen , it has exactly L value.
Now 2 atoms of a oxygen have 2L value.(Note that I mean 2O and not $O_2$here)
Well , if we take a molecule made up of 2atoms or combined i.e ($O_2$It also has L value. How is that possible ?It has bigger size and probably more atoms.
Referen... |
Consider the Oxymercuration - Demercuration of the following compound with $\ce{Hg(OAc)2}$ followed by treatment with $\ce{NaBH4}$ in basic medium:<br>
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/upjUG.png
Here, if we go according to Markovnikov addition of water to the double bond, ... |
L = $6.022*10^{22}$[![enter image description here][1]][1]
If I have one atom of oxygen , it has exactly L value.
Now 2 atoms of a oxygen have 2L value.(Note that I mean 2O and not $O_2$here)
Well , if we take a molecule made up of 2atoms or combined i.e ($O_2$It also has L value. How is that possible ?It has bigger... |
Can I write the formula of Acetic acid as HCOOCH₃ or COOHCH₃ insted of CH₃COOH would they represent the same compound with same covalent bond?
|
Are CH₃COOH and HCOOCH₃ same? |
[![This question appeared in the Indian National Chemistry Olympiad, 2016][1]][1]
The question given above appeared in the *Indian National Chemistry Olympiad (INChO), 2016*.
For this question, what I think is that the epoxide ring is being opened by a base catalysed mechanism (SN2). I proposed the following few step... |
[![Reaction of LDA with cyclohexene oxide][1]][1]
The question given above appeared in the 2016 Indian National Chemistry Olympiad (INChO). What I think is that the epoxide ring is being opened by a base-catalysed mechanism ($\mathrm{S_N2}$). I proposed the following few steps for this:
[![Proposed steps][2]][2]
... |
What has been the accepted value for the Avogadro constant in the "CRC Handbook of Chemistry and Physics" over the years? |
Why isoelectronic species give same spectral lines? |
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
$$\begin{array}{|c|c|c|c|}\hline
Edition & Year(s) & page & value \\ \hline
56 & 1975-1976 & & 6.022045(31) \times 10^{23} \\ \hline
84 & 2003-2004 & 1-7 & 6.02214199(47)\times10^{23}\\ \hline
92 & 2011-2012 & 1-1 & 6.02214179(30)\times10^{23} \\ ... |
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
$$\begin{array}{|c|c|c|c|}\hline
Edition & Year(s) & page & value \\ \hline
56 & 1975-1976 & & 6.022045(31) \times 10^{23} \\ \hline
84 & 2003-2004 & 1-7 & 6.02214199(47)\times10^{23}\\ \hline
85 & 2005 & 1-2 & 6.0221415(10)\times10^{23}\\ \hline
... |
Why isoelectronic species give similar spectral lines? |
Avogadro constant, CODATA recommended values
$$\begin{array}{|c|c|c|}\hline
Year(s) & page & value \\ \hline
1969 & 50(footnote) & 6.02252(7)\times 10^{23}\\ \hline
1973 & 25 (17.3) & 6.022176(97) \times 10^{23} \\ \hline
1986 & 6 & 6.022 136 7(36) \times 10^{23}\\ \hline
1998 & 6 & 6.022 141 99(47)\times 10^{... |
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
$$\begin{array}{|c|c|c|c|}\hline
Edition & Year(s) & page & value \\ \hline
56 & 1975-1976 & & 6.022045(31) \times 10^{23} \\ \hline
57 & 1976-1977 & F-242 & 6.022045(31) \times 10^{23} \\ \hline
84 & 2003-2004 & 1-7 & 6.02214199(47)\times10^{23}... |
Avogadro constant, CODATA recommended values
$$\begin{array}{|c|c|c|}\hline
Year(s) & page & value \\ \hline
1969 & 50(footnote) & 6.02252(7)\times 10^{23}\\ \hline
1973 & 25 (17.3) & 6.022176(97) \times 10^{23} \\ \hline
1986 & 6 & 6.022 136 7(36) \times 10^{23}\\ \hline
1998 & 6 & 6.022 141 99(47)\times 10^{... |
# What happens to water under high pressures without the possibility of escape?
It depends on what you mean for high pressure and on the temperature, however, the water phase diagram can help you to understand what will happen. This is from Wikipedia User Cmglee:
![Edited image of User:Cmglee][2]
You can see tha... |
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
$$\begin{array}{|c|c|c|c|}\hline
\text{Edition} & \text{Year(s)} & \text{page} & \text{value} \\ \hline
56 & 1975{-}1976 & & 6.022\,045(31) \times 10^{23} \\ \hline
57 & 1976{-}1977 & \text{F-242} & 6.022\,045(31) \times 10^{23} \\ \hline
84 & 20... |
L = $6.022*10^{23}$[![enter image description here][1]][1]
If I have one atom of oxygen , it has exactly L value.
Now 2 atoms of a oxygen have 2L value.(Note that I mean 2O and not $O_2$here)
Well , if we take a molecule made up of 2atoms or combined i.e ($O_2$It also has L value. How is that possible ?It has bigger... |
Does electron mass decrease when it changes its orbit? |
LPG and Candle wax both contain **saturated hydrocarbon**, yet LPG gives a clean white flame but a candle gives yellow flame with lots of smoke. Why so?
I have read some answers on web which says that it is due to the insufficient supply of oxygen, so I tried burning candle beside LPG ( *so there is* *no difference ... |
Why do different substances containing saturated hydrocarbons burns with different flame? |
Certain sun glasses having small crystals of AgCl incorporated in the lenses, on exposure to light of appropriate wavelength turns to grey colour to reduce the glare following the reaction:
AgCl
→
hv
(Grey)
Ag+Cl
If the heat of reaction for the decomposition of AgCl is 248kJ/mol
, what maximum wavelength is needed to... |
Heat of reaction for the decomposition of AgCl means? |
The IUPAC name of $(\text{CH}_3)_2\text{NH}$ is __N-Methylmethanamine__ according to [PubChem][1]. Shouldn't the locant __N-__ be dropped, given that there is no ambiguity over where the substitutent methyl may be located? (If it were attached to the carbon atom, the IUPAC name of the compound would be __Ethanamine__).... |
Why is it called N-Methylmethanamine? |
Consider the following question:
[![enter image description here][1]][1]
The first difference I noticed in these compounds was the large number of oxygen atoms in (IV). This definitely means that there is a larger availability of lone pairs in this compound. So the obvious conclusion is that compound (IV) is the ... |
# What happens to water under high pressures without the possibility of escape?
It depends on what you mean for high pressure and on the temperature, however, the water phase diagram can help you to understand what will happen. This is from Wikipedia User Cmglee:
![Edited image of User:Cmglee][2]
You can see tha... |
What are the specific conditions for a compound to have in order to show positive Fecl3 test?
I got this doubt, when I took 2 different test papers having different key for HCOOH and CH3COOH.
I never found anywhere, except for the classical example of -OH group attached to sp2 carbon, which gives FeCl3 test. |
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
$$\newcommand{\d}[2]{#1.&\hspace{-1em}#2}
\begin{array}{|c|c|c|l|}\hline
\text{Edition} & \text{Year(s)} & \text{page} & \text{value} \\ \hline
56 & 1975{-}1976 & & 6.022\,045(31) \times 10^{23} \\ \hline
57 & 1976{-}1977 & \text{F-242} & 6.022\,... |
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