instruction stringlengths 15 21.8k |
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> Which of the Following is Optically Active?
> [![enter image description here][1]][1]
I understand that for a compound to be optically active, it needs to be chiral and not have any planes of symmetry. I know **1** is symmetric, but I am confused about **2** and **3**.
[1]: https://i.stack.imgur.com/HInQ... |
**Why did Rutherford choose Alpha particles for his gold foil experiment?** |
Is there anyone here that has already analysed estrone and 17beta-estradiol on GC/MS (HP5-MS column and MSTFA as derivatizing agent)?
Is it necessary to make a mixture of other reagents with MSTFA or can I just use MSTFA in the process of derivatization? How long does that process take to happen? |
Setraline, also known as Zoloft, has a half-life of about 24 hours. If a patient is prescribed 25mg per day, won't they accumulate roughly 12.5mg of the medicine in their blood stream each day? Does the amount of ever level-off in spite of continuing to take the medicine every day? If so, how? |
When does a prescribed medicine become toxic if the half-life is more than 24 hours? |
Compound 'A':
[![enter image description here][1]][1]
Compound 'B':
[![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/pGFgV.png
[2]: https://i.stack.imgur.com/mqAfv.png
My thinking: In compound 'A', the lone pair of Nitrogen are in resonance with two other double bonds. Th... |
Which compound is more basic of the two? |
Compound 'A':
[![Compound A][1]][1]
Compound 'B':
[![Compound B][2]][2]
My thinking: In compound 'A', the lone pair of Nitrogen are in resonance with two other double bonds. The resonance chain here seems to be longer as compared to in compound 'B'. However, in compound 'B', the lone pairs of Nitrogen... |
I was told that an atom's atomic number is defined as follows:
> The number of electrons or protons present in a **neutral atom** is called atomic number. It is represented by `Z`.
What does neutral mean here? Why isn't it just "..present in an atom..."? |
> Which compound is more basic of the two?
> [![A: 1,2‐dihydropyridine; B: 1,4‐dihydropyridine][1]][1]
My thinking: In compound **A**, the lone pair of nitrogen are in resonance with two other double bonds. The resonance chain here seems to be longer as compared to in compound **B**. However, in compound **B**,... |
Which is more basic: 1,2‐dihydropyridine or 1,4‐dihydropyridine? |
I have been researching the production of peroxy acids and other strong oxidizers. I was wondering if it's possible to produce permanganic acid if I were to cast an anode with molten elemental sulfur and Manganese Dioxide from a battery?
MODERATOR, Why can't I ask new questions? |
Is it possible to synthesize permanganate electrochemically? |
I have been researching the production of peroxy acids and other strong oxidizers. I was wondering if it's possible to produce permanganic acid if I were to cast an anode with molten elemental sulfur and Manganese Dioxide from a battery?
|
If 1 mole of Ca2+ can displace 2 moles of Na+ in an ion exchange resin, can it do the same for H+? Will Ca2+ ion displace 2 moles of H+ in a strong acid resin? |
How many calcium ions is needed to displace hydronium ions in an strong acid ion exchange resin? |
I was doing some questions on equilbrium. I got stuck in this particular question.
> Identify which of the following reactions are reversible.
> $$
\begin{align}
\ce{Fe + S &-> FeS }\label{rxn:1}\tag{1}\\
\ce{NaCl + AgNO3 &-> AgCl + NaNO3}\label{rxn:2}\tag{2}\\
\ce{H2SO4 + Ba(OH)2 &-> BaSO4 + 2 H2O}\label{rxn... |
The molecular formula $\ce{(CH2O)106(NH3)16H3PO4}$ appears in the wikipedia entry for "[anoxic bodies of water][2]". A quick search suggests that it represents the product of photosynthesis, or the generic starting point for breakdown of organic matter in the nitrogen cycle, in particular the process of [denitrificati... |
What does the molecular formula (CH2O)106(NH3)16H3PO4 represent? |
I was reading an online material then I came upon a cell notation for an electrolytic cell (I determined that it was an electrolytic cell because of the absence of a salt bridge). Usually, I will proceed on reading but then I realized, since cathode and anode is switched for an electrolytic cell, which side of the cell... |
Is the cathode and anode on the cell notation of an Electrolytic cell on the same side as if how you will write it for a Galvanic cell? |
I recently have purchases a high vacuum pump and am currently repairing it, the internals have a strong smell of oil. I was going to do an oil change anyway but should i clean all of the old oil. High vacuum Oil shouldnt have a smell because that would indicate outgassing? is that right? |
Should High Vacuum oil smell? |
I am doing some research on indoor environmental quality and come across a number of spikes in CO in a dwelling.
This is a dwelling in central London with no gas-fired equipment: electric cooker and heating from a centralised district heating system.
Could this be from cooking? And/or people themselves? |
My question is how to find the number of aromatic rings in triphenylene:
[![triphenylene][1]][1]
My professor said that there are 3 aromatic rings, after which he added that the carbons of the middle rings are only supporting *ortho*-fusion of rings and hence the center ring is not to be considered.
But I am ... |
My question is how to find the number of aromatic rings in triphenylene:
[![triphenylene][1]][1]
My professor said that there are 3 aromatic rings, after which he added that the carbons of the middle rings are only supporting *ortho*-fusion of rings and hence the center ring is not to be considered.
But I am ... |
$$
\begin{align*}
2p + 5HClO + 3H_{2}O &\rightarrow 2H_{3}PO_{4} + 5HCl \\
Zn + 2HCl &\rightarrow ZnCl_{2} + H_{2} \\
Mg + CuSO_{4} &\rightarrow MgSO_{4} + Cu \\
NaOH + HNO_{3} &\rightarrow NaNO_{3} + H_{2}O
\end{align*}
$$
I want to find which of those reactions is not an oxidation-reductio... |
> Which of the following reactions doesn't represent an oxidation-reduction?
> $$
\begin{align*}
\ce{2 P + 5 HClO + 3 H2O &-> 2 H3PO4 + 5 HCl} \\
\ce{Zn + 2 HCl &-> ZnCl2 + H2} \\
\ce{Mg + CuSO4 &-> MgSO4 + Cu} \\
\ce{NaOH + HNO3 &-> NaNO3 + H2O}
\end{align*}
$$
I want to find which of ... |
I recently have purchased a high vacuum pump and am currently repairing it, the internals have a strong smell of oil. I was going to do an oil change anyway but should I clean all the old oil. High vacuum oil shouldn't have a smell because that would indicate out-gassing? Is that right? |
I’m an IT Acquisitions and Licensing specialist researching well-supported cloud software alternatives to Fujitsu’s molecular modeling [SCiGRESS][1]. I am coming in with a tech background, but little to none in chemistry, so I’m seeking the expertise of users of chemistry software.
While my online research has yield... |
I'm newish to RDKit and couldn't find an answer to this online. The following is a minimal representation of how I drew a molecule
from rdkit import Chem
from rdkit.Chem import Draw as Draw
from rdkit.Chem.rdMolDescriptors import CalcMolFormula
# .. read mol_a from file... then
print(r... |
Red Squares in RDKit? |
I would like to get the molecular structure as SMILES from Gaussian output files. OpenBabel seems to be the tool made for such tasks.
However, the structure is not always correct.
One example:
[![enter image description here][1]][1]
OpenBabel conversion Gaussian09 to SMILES (left):
N1(c2ccccc2)[C]2C=CC... |
OpenBabel: how to get correct SMILES from Gaussian output? |
What does the formula (CH2O)106(NH3)16H3PO4 represent? |
1. Interaction between atom or molecule is neglected
2. The transformation to liquid or solid is observed under appropriate condition
3. The volume of constituent atom or molecule is neglected
4. The compressibility, PV/RT is independent of pressure
I think it 's 2 and 4. But it's wrong.. why? |
I need to check my vitamin D levels regularly for my disease. It doesn't seem possible to measure at home, but measuring calcium in the blood may be more achievable since they are directly correlated. But then how can I do it? |
How can I measure calcium levels in my blood at home? |
I wanted to add a perspective to this since this can be a contentious issue, and I would still say knowing whether a nitrogen is $sp^2$ or $sp^3$ hybridized is not straightforward. I was originally hoping to add this under [this question specifically about aniline](https://chemistry.stackexchange.com/questions/30943/is... |
1. Interaction between atom or molecule is neglected
2. The transformation to liquid or solid is observed under appropriate condition
3. The volume of constituent atom or molecule is neglected
4. The compressibility, PV/RT is independent of pressure
Why 2 is wrong? in formula there is P,V,T which means under ce... |
R-PO<sub>3</sub><sup>2-</sup> is called a phoshonato group (https://www.ebi.ac.uk/chebi/searchId.do?chebiId=30931)
R-PO<sub>3</sub>H<sub>2</sub> is called a phosphono group (https://www.ebi.ac.uk/chebi/searchId.do?chebiId=48108)
So, what is :
R-PO<sub>3</sub>H<sup>-</sup>
called ? I can't find it, it seem... |
1. Interaction between atom or molecule is neglected
2. The transformation to liquid or solid is observed under appropriate condition
3. The volume of constituent atom or molecule is neglected
4. The compressibility, PV/RT is independent of pressure
Why is 2 wrong? In formula there is P,V,T which means under ce... |
I want to make a series of standards to make a calibration curve. The analyte is a volatile substance so I'll have to use some glass "containers" with a membrane lit so I don't lose too much of the analyte. The glass container has a certain volume so when making my stock solution the amount of solvent I will use is fix... |
Mass spectrometry depends on separation of the analyte based on mass to charge (m/z). ICP-MS is used to detect metals, but under the plasma conditions many of these metals could be ionised multiple times, giving them a variety of (m/z) ratios making a difficult to identify peak for any particular metal. Additionally so... |
$\ce{R-PO3^2-}$ is called a phoshonato group (https://www.ebi.ac.uk/chebi/searchId.do?chebiId=30931)
$\ce{R-PO3H2}$ is called a phosphono group (https://www.ebi.ac.uk/chebi/searchId.do?chebiId=48108)
So, what is: $\ce{R-PO3H-}$ called? I can't find it, it seems to be largely ignored.
Auxiliary question, is one o... |
For a rate law, the rate constant (k) is given by the equation: $\ln(k) = \ln(A) - \frac{E_a}{RT}$. If $k_f$ is the forward rate constant and $k_r$ is the reverse rate constant:
$\ln(k_f) = \ln(A) - \frac{E_{a,f}}{RT}$
$\ln(k_r) = \ln(A) - \frac{E_{a,r}}{RT}$
Subtracting the two equations yields:
$\ln(\frac{k... |
For a rate law, the rate constant $k$ is given by the equation
$$\ln k = \ln A - \frac{E_\mathrm{a}}{RT}$$
If $k_\mathrm{fwd}$ is the forward rate constant and $k_\mathrm{rev}$ is the reverse rate constant:
$$\ln k_\mathrm{fwd} = \ln A - \frac{E_\mathrm{a,fwd}}{RT}$$
$$\ln k_\mathrm{rev} = \ln A - \frac{E_\... |
For the following problem:
[![Ozone decomposition problem][1]][1]
the solution indicates that the rate of formation $O_2$ is $2k_2[O][O_3]$. Why isn't it $2k_2[O][O_3] + k_1[O_3]$, because the first reaction also produces $O_2$?
[1]: https://i.stack.imgur.com/R4wir.png |
Today I came across a justification of Bohr's angular momentum quantization using the De- Broglie's hypothesis.
The justification said that since the electrons are having wave nature also then while travelling in its Orbit there is starting point and ending point must concide in order to avoid destructive interferenc... |
What will happen if electron as a wave undergo destructive interference while travelling in its Orbit? |
For the following problem:
> **Example 3**: Write the rate law for $\ce{2 O3 -> 3 O2}$ given that the first step is fast and reversible, and the second step is slow.
> $$
\begin{align}
&\text{Step 1 (fast, reversible)} &\qquad \ce{O3 &<=>[$k_1$][$k_{-1}$] O2 + O} \\
&\text{Step 2 (slow)} &\qquad \ce{O + O3 &-... |
Let's say I have molten potassium hydroxide and then I add some Calcium hydroxide. I imagine, since there are hydroxide groups floating around, it would be energetically neutral for the calcium ions to bind to a "new" hydroxide group, therefore they should be floating freely with the hydroxide groups, becoming solvated... |
Are hydroxides soluble in each other? |
I don’t understand why the following question has the answers that it does:
[![2NOBr(g) -> 2NO(g) + Br_2 (g). K = 0.0142. 10.0 mol of nitrosyl bromide is placed in a 5.00 L closed vessel and allowed to decompose.][1]][1]
From what I understand, $K = \frac{\Sigma a_{products}}{\Sigma a_{reactants}}$, where a is th... |
I was reading an online material then I came upon a cell notation for an electrolytic cell (I determined that it was an electrolytic cell because of the absence of a salt bridge). Usually, I will proceed on reading but then I realized, since cathode and anode is switched for an electrolytic cell, which side of the cell... |
I don’t understand why the following question
> The decomposition of nitrosyl bromide $(\ce{NOBr})$ proceeds by the following reaction:
> $$\ce{2 NOBr(g) <=> 2 NO(g) + Br2(g)} \qquad K = 0.0142$$
> Calculate the $[\ce{NOBr}],$ $[\ce{NO}],$ and $[\ce{Br2}]$ when $\pu{10.0 mol}$ of nitrosyl bromine is placed in ... |
>One of my Chemistry professors said that the hard mass formed after adding water to Plaster of Paris, cannot be converted back into Plaster of Paris. However, he said that the original Gypsum can be heated to make Plaster of Paris.
What causes the hard mass not to convert back into POP by adding water even though the... |
I have to complete an experiment for school where I have copper and zinc electrodes placed into an electrolyte of copper sulfate and I have measured the potential across it at varying temperatures. For example at 60°C (333K) I measured the potential to be 0.880 volts and at 75°C (348K) I measured the potential to be 0.... |
How do you calculate a half cell potential Copper(II) and Copper Sulfate? |
What is the difference between the two? In my assignment book there is this question which asks if enthalpy of combustion is greater than, equal to or less than the heat of combustion. The answer given is that heat of combustion is greater and I don't understand why |
What's greater, enthalpy of combustion or heat of combustion? |
For a rate law, the rate constant $k$ is given by the equation
$$\ln k = \ln A - \frac{E_\mathrm{a}}{RT}\tag{1}$$
If $k_\mathrm{fwd}$ is the forward rate constant and $k_\mathrm{rev}$ is the reverse rate constant:
$$\ln k_\mathrm{fwd} = \ln A - \frac{E_\mathrm{a,fwd}}{RT}\tag{2}$$
$$\ln k_\mathrm{rev} = \ln... |
I don’t understand why the following question
> The decomposition of nitrosyl bromide $(\ce{NOBr})$ proceeds by the following reaction:
> $$\ce{2 NOBr(g) <=> 2 NO(g) + Br2(g)} \qquad K = 0.0142$$
> Calculate the $[\ce{NOBr}],$ $[\ce{NO}],$ and $[\ce{Br2}]$ when $\pu{10.0 mol}$ of nitrosyl bromine is placed in ... |
What is a "ynoate" in the context of alkynes? |
$\ce{R-PO3^2-}$ is called a phoshonato group (https://www.ebi.ac.uk/chebi/searchId.do?chebiId=30931)
$\ce{R-PO3H2}$ is called a phosphono group (https://www.ebi.ac.uk/chebi/searchId.do?chebiId=48108)
So, what is: $\ce{R-PO3H-}$ called ? I can't find it, it seems to be largely ignored.
Auxiliary question, is one ... |
I have to complete an experiment for school where I have copper and zinc electrodes placed into an electrolyte of copper sulfate and I have measured the potential across it at varying temperatures. For example at $\pu{60°C}$ ($\pu{333K}$) I measured the potential to be $\pu{0.880 volts}$ and at $\pu{75°C}$ ($\pu{348K}$... |
The thermodynamic equilibrium constant $K$ (different from both $K_p$ and $K_c$) and the reaction quotient $Q$ are defined with reference to a standard state. When all reactants and products are at standard state, $Q = 1$. $K$ and $Q$ are related to the Gibbs energy of reaction via:
$$\Delta_\mathrm{r}G = RT \ln\frac{... |
I don’t understand why the following question
> The decomposition of nitrosyl bromide $(\ce{NOBr})$ proceeds by the following reaction:
> $$\ce{2 NOBr(g) <=> 2 NO(g) + Br2(g)} \qquad K = 0.0142$$
> Calculate the $[\ce{NOBr}],$ $[\ce{NO}],$ and $[\ce{Br2}]$ when $\pu{10.0 mol}$ of nitrosyl bromine is placed in ... |
If a patient is prescribed 25mg per day of a compound that has a half-life of roughly 24 hours, what is the maximum accumulated amount of the medicine that would build in the patients body? |
What is the maximum amount of medicine that could accumulate in the body if the compound has a half-life of 24 hours? |
What is the oxidation state of $\ce{Mn}$ in $\ce{HMn(CO)5}$? If $\ce{H}$ has an oxidation state of $+1$, then $\ce{Mn}$ should have oxidation state of $-1$, which I'm not sure is possible.
On the other hand, if $\ce{H}$ has an oxidation state of $-1$, then $\ce{Mn}$ has an oxidation state of $+1$. However, [Wikipedi... |
What is the oxidation state of Mn in HMn(CO)5? |
**There are many ways to make simple pH buffers like this one**. As @Poutnik noted, preparation via titration works fine and in very commonly used. To illustrate how this is done, several possibilities are presented. Assume the desired buffer characteristics are pH = 4.5, concentration = 0.5 M, final buffer volume = 1 ... |
**There are many ways to make simple pH buffers like this one**. As @Poutnik noted, preparation via titration works fine and in very commonly used. To illustrate how this is done, several possibilities are presented. Assume the desired buffer characteristics are pH = 4.5, concentration = 0.5 M, final buffer volume = 1 ... |
Please, let me know which an open free molecular modelling program will apply
the B3LYP/G-31G(d,p) density functional level of theory? Thanks.
Helen |
Which of the free access molecular modelling program apply the B3LYP/G-31G(d,p) level of theory? |
>I believe have found a answer.
It's valid mathematically, make sense physically but I don't know if chemically is true.
I posted to community appreciation.
There we go!
----------
**The reactions**
1. *ionization of weak acid*:
$$\ce{HA + H2O <=> H3O+ + A-}\qquad K_\ce{a}=\frac{\ce{[H3O+][A-]}}{\ce{[HA]}}... |
I was looking at the code required for a simple RHF computation when I came across the section for the diagonalisation of the Fock Matrix.
Based on what I know, the diagonal matrix **s** is evaluated as
**s** = **U†SU**, where **S** is the overlap matrix.
The matrix **X** is then evaluated as
**X** = **... |
When diagonalising the overlap matrix, what happens if the square root of the diagonal matrix does not exist? |
Why does nitrogen molecule have greater ionization energy than nitrogen atom? |
I’m an IT Acquisitions and Licensing specialist researching well-supported cloud software alternatives to Fujitsu’s molecular modeling [SCiGRESS][1]. I am coming in with a tech background, but little to none in chemistry, so I’m seeking the expertise of users of chemistry software.
While my online research has yield... |
1. I've synthesized the compound potassium trioxalatocobaltat (III) trihydrat and for it I have two reaction equations. One of them is:
$$\ce{CoCO_3 + 3K_2C_2O_4.2H_2O -> [Co(C_2O_4)_3]K_2 + 2CO_2}$$
and the other:
$$\ce{[Co(C_2O_4)_3]K_2 + PbO_2 -> [Co(C_2O_4)_3]K_3.3H_2O}$$
I see that the lead dioxide oxi... |
1. I've synthesized the compound potassium trioxalatocobaltate(III) trihydrate and for it I have two reaction equations. One of them is:
$$\ce{CoCO3 + 3K2C2O4.2H2O -> K2[Co(C2O4)3] + 2CO2}$$
and the other:
$$\ce{K2[Co(C2O4)3] + PbO2 -> K3[Co(C2O4)3].3H2O}$$
I see that the lead dioxide oxidizes $\ce{Co^2+}$ ... |
What is Liebermann nitroso test? |
I recently ran into [this][1] paper which describe experiments that confirm that hemoglobin is photoconductive. Finding this fact as incredible, I wanted to read up more on photoconductive properties of hemoglobin. The paper does not discuss what the conductivity number is, that would give some estimate of charge carri... |
I was looking at the code required for a simple RHF computation when I came across the section for the diagonalisation of the Fock Matrix.
Based on what I know, the diagonal matrix **s** is evaluated as
**s** = **U†SU**, where **S** is the overlap matrix.
The matrix **X** is then evaluated as
**X** = **... |
I have looked this theory up on google and found that the theory is that when metal is burnt calx (metal oxide) and phlogiston is created (metal --> calx + phlogiston). Then I found out that phlogiston is a substance supposed by 18th century scientists to exist in all combustible bodies and to be released during combus... |
>I believe have found a answer.
It's valid mathematically, make sense physically but I don't know if chemically is true.
I posted to community appreciation.
There we go!
----------
**The reactions**
1. *ionization of weak acid*:
$$\ce{HA + H2O <=> H3O+ + A-}\qquad K_\ce{a}=\frac{\ce{[H3O+][A-]}}{\ce{[HA]}}... |
It is well-established that a Lewis acid catalyst (popularly ZnCl2) is necessary to form an alkyl chloride when reacting HCL with a primary alcohol. This actually changes the mechanism: the lewis acid complexes with the alcohol and the resulting leaving group is [Zn(OH)Cl2]- instead of water. For HBR and HI this is tec... |
Will a lewis acid catalyze the reaction of HBR with primary alcohols? |
Why CO is a stronger and more common ligand than N2? |
It is well-established that a Lewis acid catalyst (popularly ZnCl2) is necessary to form an alkyl chloride when reacting HCl with a primary alcohol. This actually changes the mechanism: the lewis acid complexes with the alcohol and the resulting leaving group is [Zn(OH)Cl2]- instead of water. For HBr and HI this is tec... |
Will a lewis acid catalyze the reaction of HBr with primary alcohols? |
It is well-established that a Lewis acid catalyst (popularly $\ce{ZnCl2})$ is necessary to form an alkyl chloride when reacting $\ce{HCl}$ with a primary alcohol. This actually changes the mechanism: the Lewis acid complexes with the alcohol and the resulting leaving group is $\ce{[Zn(OH)Cl2]-}$ instead of water. For $... |
Will a Lewis acid catalyze the reaction of HBr with primary alcohols? |
1. I've synthesized the compound potassium trioxalatocobaltate(III) trihydrate and for it I have two reaction equations. One of them is:
$$\ce{CoCO3 + 3K2C2O4.2H2O -> K2[Co(C2O4)3] + 2CO2}$$
and the other:
$$\ce{K2[Co(C2O4)3] + PbO2 -> K3[Co(C2O4)3].3H2O}$$
I see that the lead dioxide oxidizes $\ce{Co^2... |
If you made the anode and cathode both out of a single piece of zeolite that has been coated inside with graphite (or graphene) wouldn’t that provide a conductive path and greater surface area thus making electrolysis of water more efficient? |
A more efficient method for electrolysis? |
How come enzymes with a lower Km are more easily saturated with substrate than an enzyme with higher Km?
Is it because enzymes with higher Km are able to bind substrate and hold onto it tighter and therefore have a higher chance of becoming a product?
I'm confused because shouldn't a lower Km indicate that an enz... |
How come enzymes with a lower $K_\mathrm{m}$ are more easily saturated with substrate than an enzyme with higher $K_\mathrm{m}?$
Is it because enzymes with higher $K_\mathrm{m}$ are able to bind substrate and hold onto it tighter and therefore have a higher chance of becoming a product?
I'm confused because shoul... |
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