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For *E1 selection rules* (embodied in the electronic transition moment), to have an allowed transition the direct product of irreducible representations (IRs) must contain the totally symmetric IR. So, for transitions between two $\Sigma$ states, the following transitions are symmetry allowed: $\Sigma^- \leftrightarrow... |
How to name this organic isomer compound? |
> We happen to be measuring aqueous solutions instead, so I am trying to identify useful reference solutions we can prepare.
This experiment is really problematic. mid-IR is not meant for aqueous solutions. Water is a no-no in infrared spectroscopy. Look at the low transmittance of water in mid IR range. Liquid wate... |
Why IUPAC Nomenclature of following amine is written as **2-methylpropan-2-amine** and not as as *2,2-dimethylethanamine*?
[![2-methylpropan-2-amine][1]][1]
[1]: https://i.stack.imgur.com/hVS8t.png |
Why IUPAC name this amine is written as 2-methylpropan-2-amine and not as 2,2-dimethylethanamine? |
I read [this](https://chemistry.stackexchange.com/questions/61107/is-cis-1-2-dimethylcyclohexane-a-meso-compound) question and it's answer by **@orthocresol**. Now, he has written that the compound in question is meso not because there is a plane of symmetry but because of the rapid flipping of the cyclohexane ring, wh... |
Is it correct to look at plane of symmetry in cyclohexane for determining a meso compound? |
I read [this](https://chemistry.stackexchange.com/questions/61107/is-cis-1-2-dimethylcyclohexane-a-meso-compound) question and it's answer by **@orthocresol**. Now, he has written that the compound in question is meso not because there is a plane of symmetry but because of the rapid flipping of the cyclohexane ring, wh... |
I read [this](https://chemistry.stackexchange.com/questions/61107/is-cis-1-2-dimethylcyclohexane-a-meso-compound) question and it's answer by **@orthocresol**. Now, he has written that the compound in question is meso not because there is a plane of symmetry but because of the rapid flipping of the cyclohexane ring, wh... |
Is it correct to look at plane of symmetry in substituted cyclohexane for determining a meso compound? |
Disclaimer: I assume you refer to compounds which may be «soluble in water», not necesarily to constrained to «recording the spectra in aqueous solution» for limitations of IR transmission spectroscopy which are a bit lesser present with IR [ATR][1] spectroscopy, and basically not present for Raman (M. Farooq's answer)... |
Why is it that chemisorption decreases with higher temperatures?
The explanations I found online were quite vague and one of them cited Le Chatelier's principle, but I thought chemisorption is an irreversible process (because covalent bonds are formed between the adsorbate and adsorbent) so there is no reversible e... |
Why does chemisorption decrease with increasing temperatures? |
I was reading about purification of organic compounds and I came across [**this**](https://drive.google.com/file/d/1Ozl907kGjmN6tJRg8riFCgdmJUlI3KyX/view?usp=drivesdk).
I quote below, a line from the excerpt that caused my confusion.
>The organic solvent is later removed by distillation or by evaporation to get ba... |
Imagine I have 5 g of vineger which I titrated with 33 mL of 0.1M Sodium Hydroxide (NaOH).
I tried V₁S₁=V₂S₂ formula but It needs the volume of the acid.
I have tried to calculate the volume with W=SVM/1000 formula which gives me 250/3S mL (where S is the molarity of Acetic Acid), but at the end S is cancelled ou... |
I was reading about purification of organic compounds and I came across [**this**](https://drive.google.com/file/d/1Ozl907kGjmN6tJRg8riFCgdmJUlI3KyX/view?usp=drivesdk).
I quote below, a line from the excerpt that caused my confusion.
>The organic solvent is later removed by distillation or by evaporation to get ba... |
Why is it that chemisorption decreases with higher temperatures?
The explanations I found online were quite vague and one of them cited Le Chatelier's principle, but I thought chemisorption is an irreversible process (because covalent bonds are formed between the adsorbate and adsorbent) so there is no reversible e... |
While documenting myself on the detectors used in HPLC, I came across one that I did not know: ELSD.
I understood that the sample with the mobile phase was nebulized at the column outlet but I do not understand what is measured next.
Could you clarify this for me?
Thank you for your help |
Combound with pressure sensitive melting point at moderate temperature and pressure? |
I take 1g of zinc metal and after dissolving, diluting it to 500 ml and adjust the PH of 50 ml of it to make titration with an unknown concentration of EDTA.
I found 1g of zinc took 25 ml of EDTA that means 0.004 g of zinc equivalent to 1ml of unknown concentration of EDTA.
my question is how can I calculate the ... |
what is the concentration of EDTA after titration with Zinc Metal? |
While documenting myself on the detectors used in HPLC, I came across one that I did not know: ELSD.
I understood that the sample with the mobile phase was nebulized at the column outlet but I do not understand what is measured next.
Could you clarify this for me? |
In [this answer on Physics Stack Exchange,][1] the author states that conductance $G$ is related to $\sigma$ by $$G = \sigma\frac{A}{l}$$
where $A$ is the cross-sectional area perpendicular to the direction of electric current and $l$ is the length of the conductor.
How does this relate to the conductivity of solve... |
I dried out some blue copper sulphate in an oven to see if it would turn white which it did.
When I put some water drop by drop on it it did not return to the original bright blue. Instead it took on a more purple colour.
Why did this happen ?
The copper sulphate was bought from an chemistry chemicals supplier... |
Why is my dried out copper sulphate purple when wetted with water? |
Rare earth and platinum group metals are often found clustered together in the earth's crust. Mining for platinum, for instance, also yields Rhodium and Ruthenium belonging to the same group. Likewise, rare earth elements such as Neodymium, Europium and Samarium also cooccur together in the same ore so much so that the... |
**Please edit the table to include missing data**
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
| Edition | Years(s) | page | value | CODATA? |
|---------|-----------|-------|--------------|-------------------|
| 1 [(Link)](https://books.google.com/books?id=07AHIEp6vYQC&printse... |
Directing Group assisted Pd catalyzed (sp2)*meta*-C-H functionalization has a growing attention in recent years.
In addition, few examples can be found for *meta*-C-H functionalization via Rhodium. I am wondering whether it is possible to do *meta*-C-H functionalization using Cobalt as its a first-row transtion metal.... |
I dried out some blue copper sulphate in an oven to see if it would turn white which it did.
I can't remember exactly but I left it overnight in the oven at around 50 C. It was white the following day.
When I put some water drop by drop on it it did not return to the original bright blue. Instead it took on a more... |
Why is my dried out copper sulphate green when wetted with water? |
In [this answer on Physics Stack Exchange][1], the author states that conductance $G$ is related to conductivity $\sigma$ by $$G = \sigma\frac{A}{l}$$
where $A$ is the cross-sectional area perpendicular to the direction of electric current and $l$ is the length of the conductor.
How does this relate to the conducti... |
**Please edit the table to include missing data**
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
| Edition | Years(s) | page | value | CODATA? |
|---------|-----------|-------|--------------|-------------------|
| 1 [(Link)](https://books.google.com/books?id=07AHIEp6vYQC&printse... |
**Please edit the table to include missing data**
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
| Edition | Years(s) | page | value | CODATA? |
|---------|-----------|-------|--------------|-------------------|
| 1 [(Link)](https://books.google.com/books?id=07AHIEp6vYQC&printse... |
Municipal water treatment often includes [both chlorine *and* ammonia](https://www.wqa.org/Learn-About-Water/Common-Contaminants/Ammonia), creating chloramines for a stronger effect.
The color from the reaction with *ammonium hydroxide* is [here](https://www.youtube.com/watch?v=7TIIOj-SHkw) - I don't think this matc... |
With $M=$the molar mass of the component, $n$ represent the moles and $m$ the mass.
I've wondered about this being true, $n_{solvent}+n_{solute}=\frac{M}{m_{solvent}+m_{solute}}$ because of $n=\frac{m}{M}$ and $n=n_{solvent}+n_{solute}$ and $m=m_{solvent}+m_{solute}$? I don't think this is true either but I wanted t... |
Is $n_{solvent}+n_{solute}=\frac{M}{m_{solvent}+m_{solute}}$ true? |
The answer to this question is actually pretty interesting, I think. @user55119 's comment that the principal chain is the cyclohexane ring is correct -- but it seems like you understand that that's what the teacher is saying, and you're asking, "why?" The best short answer, too, is imho in your comments: @MaxW 's "n... |
Are amides more acidic than alcohols? I thought this regarding a secondary amide and a tertiary alcohol functional group since amides have both electronegative oxygen and nitrogen, compared to alcohol which just has an oxygen |
2.00 g of a gas mixture of H2
and N2 have a volume of 10.0 L at 700. mmHg
and 63.0 °C. Calculate the vol.% and the partial pressures of the two gases in
the mixture.
I have only found the total number of moles using the formula:*PV=nRt*
But i cant get any further! Any ideas? |
I read [this](https://chemistry.stackexchange.com/questions/61107/is-cis-1-2-dimethylcyclohexane-a-meso-compound) question and it's answer by **@orthocresol**. Now, he has written that the compound in question is meso not because there is a plane of symmetry but because of the rapid flipping of the cyclohexane ring, wh... |
A gas mixture of $\ce{H2}$ and $\ce{N2}$ weighs $\pu{2.00 g}$ and have a volume of $\pu{10.0 L}$ at $\pu{700 mmHg}$ and $\pu{63.0 °C}$. Calculate the vol.% and the partial pressures of the two gases in the mixture.
I have only found the total number of moles using the formula:$PV=nRT$.
But I cant get any further... |
While documenting myself on the detectors used in HPLC, I came across one that I did not know: ELSD.
I understood that the sample with the mobile phase was nebulized at the column outlet but I do not understand what is measured next.
Could you clarify this for me? |
I did the numbering by taking all the functional groups in principal chain (scheme **A**), but my teacher did it differently and proposed the name **cyclohexane‐1,3‐dicarboxylic acid** (scheme **B**):
[![numbering schemes for cyclohexane‐1,3‐dicarboxylic acid][1]][1]
The principal chain in my teacher's answer is ... |
Is cyclohexane‐1,3‐dicarboxylic acid a correct IUPAC name? |
Can the total amount of solution be found as a ratio between molar mass of a component and total mass of solution? |
Can chalk explode? |
I am a physics student, with little experience in chemistry. I am researching for a project which involves freezing and its capabilities on humans and different minerals like chalk.
I have been researching chalk for the last couple of months as part of my project. Can the cracks generated cause the mineral to break ... |
Can freezing temperatures cause chalk to fragment? |
In the Hall–Héroult process of extracting aluminium from aluminium oxide, the electrolyte is a liquid mixture of cryolite $(\ce{NaAlF6})$ and aluminium oxide $(\ce{Al2O3}).$ The cathodes and the anodes are made of graphite.
During the electrolysis process, aluminium is deposited at the cathode and oxygen is liberat... |
Why do they use graphite electrodes in the Hall–Héroult process? |
Point mutations are divided into two categories: transitions and transversions. Since point mutations only occur during DNA replication (an integral process of both mitosis and meiosis), the mutated nitrogenous bases only appear on the newly synthesized DNA strands, rather than on the parental strands that serve as tem... |
How do point mutations affect complementary base-pairing and widths of the nucleotide pairs? |
Recently, I was learning about electrode processes and I came across the topic of "*electrode potentials*".
I understood that at equilibrium, a potential difference was generated at the interface between the electrode and the electrolyte because of the formation of an [electric double layer][1].
I was reading
[th... |
[Ferrite magnet](https://en.wikipedia.org/wiki/Ferrite_(magnet)) is a ceramic material and consists of agglomerated crystalline domains with spinel structure. Like other ceramic materials, ferrite magnets are brittle. For example, here is a photo of newly manufactured $\ce{Sr_xBa_{1-x}FeO2}$ tablet which already has ch... |
Can a ferrite magnet be impregnated with polymer to reduce its fragility? |
**1. Enthalpy of reaction** defined as the enthalpy change observed in a constituent of a thermodynamic system when one mole of substance reacts completely.
**2. Enthalpy of formation** defined as the enthalpy change observed in a constituent of a thermodynamic system when one mole of a compound is formed from its... |
**1. Enthalpy of reaction** defined as the enthalpy change observed in a constituent of a thermodynamic system when one mole of substance reacts completely.
**2. Enthalpy of formation** defined as the enthalpy change observed in a constituent of a thermodynamic system when one mole of a compound is formed from its... |
I am not sure the 3D conformation stills as reported on PubChem are all that accurate. Although crystal structures are sometimes referenced for specific molecules, some of the displays are in fact <i>models</i>, some of which do not make sense to me.
Here are some observations regarding the three molecules you note... |
>Are amides more acidic than alcohols?
This is very broad question. The very short and general answer would be both have similar acidities (as Mithoron pointed out in his comment elsewhere). To support this statement, there is some evident in the Table provided by [UMass website][1] that mentioned by Waylander in ... |
I stumbled across this problem which I don't understand the answer to:
Which solid is much more soluble in 1 M $\ce{HCl}$ than in $\ce{H2O}$?
(A) $\ce{CaHPO_4}$
(B) $\ce{CaCl_2}$
(C) $\ce{BaBr2}$
(D) $\ce{BaSO4}$ |
I take $\pu{1g}$ of zinc metal and after dissolving, diluting it to $\pu{500 ml}$ and adjust the $\mathrm{pH}$ of $\pu{50 ml}$ of it to make titration with an unknown concentration of EDTA.
I found $\pu{1g}$ of zinc took $\pu{25 ml}$ of EDTA that means $\pu{0.004 g}$ of zinc equivalent to $\pu{1ml}$ of unknown conce... |
I'll try and answer your question, but a "full" answer would take a book.
Given the reaction:
$$\ce{aA + bB <=> cC + dD}$$
Then assuming an [elementary reaction](https://en.wikipedia.org/wiki/Elementary_reaction) in the gaseous state the concentration equilibrium constant will be:
$$\mathrm{K_c} = \dfrac{[... |
I'll try and answer your question, but a "full" answer would take a book.
Given the reaction:
$$\ce{aA + bB <=> cC + dD}$$
Then assuming an [elementary reaction](https://en.wikipedia.org/wiki/Elementary_reaction) in the gaseous state the concentration equilibrium constant will be:
$$\mathrm{K_c} = \dfrac{[... |
What is the mechanism for this reaction? The tertiary amine is converted into an amide and the ring gains a double bond. I can't figure out how the C-O double bond would be formed.
I believe this reaction is in the 2014 IChO preparatory problems.
[![enter image description here][1]][1]
[1]: https://i.s... |
Mechanism for this ring opening reaction? |
[![Fig][1]][1]
[1]: https://i.stack.imgur.com/3VVn1.png
My question is illustrated as the figure. As far as I know, due to the Franck-Condon principle, the absorption spectrum is related to the ground state to the excited state with the same geometry. Here I marked as $|X \nu_0\rangle \rightarrow |A \nu_m \ra... |
What type of spectroscopy can display several vibrational energy levels around the electronic transition? |
What is the mechanism for this reaction? The tertiary amine is converted into an amide and the ring gains a double bond. I can't figure out how the C-O double bond would be formed.
Help would be much appreciated.
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/BzmBS.png
|
[![Fig][1]][1]
[1]: https://i.stack.imgur.com/3VVn1.png
My question is illustrated as the figure. As far as I know, due to the Franck-Condon principle, the absorption spectrum is related to the ground state to the excited state with the same geometry. Here I marked as $|X \nu_0\rangle \rightarrow |A \nu_m \ra... |
What is the mechanism for this reaction? The tertiary amine is converted into an amide and the ring gains a double bond. I can't figure out how the C-O double bond would be formed.
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/BzmBS.png
|
From the definition of entropy change,
$$S_2-S_1=\left ( \int_{1}^{2} \frac{\delta Q}{T}\right )_{int.rev}$$
From the closed system entropy balance, we have
$$S_2-S_1=\left ( \int_{1}^{2} \frac{\delta Q}{T}\right )_{b}+\sigma $$
where $\sigma$ is the entropy produced within the system, vanishing to zero in t... |
How can change in entropy be the same for all processes if the entropy production $\sigma$ is present for irreversible processes? |
I have the $\Delta T$, I have the specific heat of the calorimeter, I have known weights/mass. I know the salt is lithium-based. What steps do I take to calculate the enthalpy of the solution so I can compare my answer to the specific molar enthalpies of possible lithium salts?
If the equation I use is $Q = m \times... |
I have the $\Delta T$, I have the specific heat of the calorimeter, I have known weights/mass. I know the salt is lithium-based. What steps do I take to calculate the enthalpy of the solution so I can compare my answer to the specific molar enthalpies of possible lithium salts?
If the equation I use is $Q = m \cdot ... |
I have read 2 formulas for kinetic energy of 1 mol of gas - 3/2 kT and 1/2fRT . But if I equate them then f comes out to be 3 . But f is different of mono, di, polyatomic gases . Where am I wrong in my deduction that 3/2kT = 1/2 fRT ? |
Which formula for kinetic energy of 1 mol of a gas is more acceptable? |
I have the $\Delta T$, I have the specific heat of the calorimeter, I have known weights/mass. I know the salt is lithium-based. What steps do I take to calculate the enthalpy of the solution so I can compare my answer to the specific molar enthalpies of possible lithium salts?
If the equation I use is $Q = m \times... |
I have read 2 formulas for kinetic energy of 1 mol of gas - 3/2 RT and 1/2fRT . But if I equate them then f comes out to be 3 . But f is different of mono, di, polyatomic gases . Where am I wrong in my deduction that 3/2RT = 1/2 fRT ? |
**Please edit the table to include missing data**
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
| Edition | Years(s) | page | value | CODATA? |
|---------|-----------|-------|--------------|-------------------|
| 1 [(Link)](https://books.google.com/books?id=07AHIEp6vYQC&printse... |
I'll try and answer your question, but a "full" answer would take a book.
Given the reaction:
$$\ce{aA + bB <=> cC + dD}$$
Then assuming an [elementary reaction](https://en.wikipedia.org/wiki/Elementary_reaction) in the gaseous state the concentration equilibrium constant will be:
$$\mathrm{K_c} = \dfrac{[... |
I attempted to prepare saturated citric acid solution from anhydrous powder. According to online data, the solubility limit was 59.2 w/w at 20C, i.e. 59.2 g citric acid in 100 mL water. To ensure full saturation (as in the case of preparing brine solution), I ended up weighing 67 g of the powder and tried adding 100 mL... |
How do I prepare citric acid solution (from anhydrous powder) of accurate concentration, given that the solution volume expands when water is added? |
I have read 2 formulas for kinetic energy of 1 mol of gas - 3/2 RT and 1/2fRT . But if I equate them then f comes out to be 3 . But f is different of mono, di, polyatomic gases . Where am I wrong in my deduction that 3/2RT = 1/2 fRT ? Do these 2 formulas produce same result for a particular gas? |
Which formula for kinetic energy of 1 mol of a gas is universally applicable? |
Considering the Aqueous $NaCl$ is already concentrated. If we were to use copper electrodes instead of inert graphite electrodes:
Would copper react with the evolved chlorine gas to give $CuCl_2$ in solution, whilst still giving hydrogen gas at the cathode? Since in my experimentation, I obtained a teal blue green col... |
Considering the aqueous $\ce{NaCl}$ is already concentrated. If we were to use copper electrodes instead of inert graphite electrodes:
Would copper react with the evolved chlorine gas to give $\ce{CuCl2}$ in solution, whilst still giving hydrogen gas at the cathode? Since in my experimentation, I obtained a teal blu... |
My bottle of ferrous chloride powder/crystals was years in shelf and it turned dark brown. If I break up the clumps I can see a little bit of yellow layers. I suspect it's a combination of iron oxide and ferric chloride.
I want to convert it back to green ferrous chloride and I'm looking for cheap ways to do that. M... |
We all have read that 1 mole of any substance contains $6.022 \times10^{23}$ atoms included in the substance. And:
$$Mole=\frac{weight}{molar\,\,mass}$$
Where molar mass is gram atomic mass such that when the atomic mass of the element (expressed in unified mass) is expressed in grams, then that amount contains $6.... |
Basis of mole concept? |
This is a [Google ngram](https://books.google.com/ngrams/graph?content=(Zinc+-+_START_+Zinc)%2Czinc%2C(Iodine+-+_START_+Iodine)%2Ciodine%2Cnitrogen%2C(Nitrogen+-+_START_+Nitrogen)%2Ccarbon%2C(Carbon+-+_START_+Carbon)&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2C%28Zinc%20-%20%20_START_%... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/9vowE.jpg
Here in case of (1) it is more favorable towards $S_N1$ reaction as it will create Benzyl carbocation which is very stable
(2) Here it is more favorable towards $S_N1$ as it is first of all Allyl Carbocation and in resonance w... |
[![enter image description here][1]][1]
Here in case of (1) it is more favorable towards S<sub>N</sub>1 reaction as it will create benzyl carbocation which is very stable.
(2) Here it is more favorable towards S<sub>N</sub>1 as it is first of all allyl carbocation and in resonance with the benzene and the double ... |
I'm looking at a cycloaddition that produces a bicyclic intermediate, there are two different ways of doing the addition which can be described as <i>endo</i>/<i>exo</i>. However, all three bridges are the same length. How do I assign priorities and <i>endo</i>/<i>exo</i> here?
Here's a simplified example of this re... |
Consider the following question:
**For oxidation of iron, $4Fe(s)+3H_2O(g)\to2Fe_2O_3(s)+3H_2(g)$ entropy change is $–549.4 \ JK^{-1}mol^{-1}$ at $298 K$. Inspite of negative entropy change of this reaction, why is the reaction spontaneous? ($∆_rH^0$ for this reaction is $–1648 × 103 \ Jmol^{–1}$)**
In this quest... |
What you have shown in red is the second propagation step in the benzylic free radical bromination of ethylbenzene. The bond dissociation energy (BDE) of bromine is +46 kcal/mol while the overall heat of reaction of the step is -12 kcal/mol. Thus, the formation of the C-Br bond must be -58 kcal/mol. The BDE for the C-... |
Consider the following question:
> For the oxidation of iron,
$$\ce{4Fe(s) + 3H_2O(g)\to 2Fe_2O_3(s) + 3H_2(g)}$$
>the entropy change is $ \pu{ –549.4 JK^{-1}mol^{-1}}$ at 298 K. In spite of the negative entropy change of this reaction, why is the reaction spontaneous? ($\Delta_r H^o$ for this reaction is $\... |
What you have shown in red is the second propagation step in the benzylic free radical bromination of ethylbenzene. The bond dissociation energy (BDE) of bromine is +46 kcal/mol while the overall heat of reaction of the step is -12 kcal/mol. Thus, the formation of the C-Br bond must be -58 kcal/mol. The BDE for the C-... |
**The factors that generate mineral concentrations are complex and often only partly known**
*Introduction: geology is complicated*
The one thing we can be very certain about is is that the distribution of minerals in the earth's crust has very little to do with the primordial origins of the component elements (t... |
I'll try and answer your question, but a "full" answer would take a book.
Given the reaction:
$$\ce{aA + bB <=> cC + dD}$$
Then assuming an [elementary reaction](https://en.wikipedia.org/wiki/Elementary_reaction) in the gaseous state the concentration equilibrium constant always has products over reactants an... |
I would like to perform an optimization calculation using the functional M06-2x using the BJ dispersion correction in Gaussian 0.9. However, I can't find the parameters for this functional as I found for example for B3LyP. Has anyone worked with this? |
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