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Why is the y intercept of a G vs X curve treated as chemical potential? |
While researching how to identify cations in a solution I found that ammonia could be used to distinguish between AgCl and PbCl2 precipitates after HCl had been added.
Why does the addition of ammonia cause PbCl2 to dissolve while AgCl doesn't? (With chemical equations if possible) |
I present another (almost) two-step synthesis, involving the famous [Wittig reaction](https://en.wikipedia.org/wiki/Wittig_reaction). The first step details the preparation of a phosphonium ylide, which subsequently is allowed to react with the carbonyl compound (benzophenone in our case) to yield the final product, 1,... |
While researching how to identify cations in a solution I found that ammonia could be used to distinguish between $\ce{AgCl}$ and $\ce{PbCl2}$ precipitates after $\ce{HCl}$ had been added.
Why does the addition of ammonia cause $\ce{PbCl2}$ to dissolve while $\ce{AgCl}$ doesn't? (With chemical equations if possible... |
so I managed to derive an equation that gave me the volume of base required to get a certain pH. From there I generated a pH titration curve. And from there I determined the degree of ionisation at the various pHs for each chemical species and then used that to determine the conductivity of the solution. The derivation... |
so I managed to derive an equation that gave me the volume of base required to get a certain pH. From there I generated a pH titration curve. And from there I determined the degree of ionisation at the various pHs for each chemical species and then used that to determine the conductivity of the solution. The derivation... |
Hi all so I managed to derive an equation that gave me the volume of base required to get a certain pH. From there I generated a pH titration curve. And from there I determined the degree of ionisation at the various pHs for each chemical species and then used that to determine the conductivity of the solution. The der... |
While searching how to identify cations in a solution I found that ammonia could be used to distinguish between $\ce{AgCl}$ and $\ce{PbCl2}$ precipitates after $\ce{HCl}$ had been added.
Why does the addition of ammonia cause $\ce{PbCl2}$ to dissolve while $\ce{AgCl}$ doesn't? (With chemical equations if possible.) |
I am confused about the structure of bridging complexes with the bridging ligands as OH- or NH2-. Aren't they both monodentate ligands? and if they form a simple co-ordinate bond, then the negative charge on them must be lost, but then the oxidation states of the metal atoms doesn't match.
For example,
[![Tetraaqua... |
The main question is that is scolopamine extracted from datura or Brugmansia scolopamine freebase or scolopamine hydrobromide? |
Is scolopamine same as scolopamine hydrobromide? |
The main question is that is scolopamine extracted from datura or Brugmansia scolopamine freebase or scolopamine hydrobromide?
It is extracted via methanol or acetone from leaves and Seeds |
$\ce{CuSO4}$ is acidic salt because it is made up of $\ce{Cu(OH)2}$ (weak base) and $\ce{H2SO4}$ (strong acid). But why $\ce{[CuSO4.4H2O]H2O}$ is amphoteric? |
Why anhydrous copper sulphate is acidic in nature but pentahydrate copper sulphate is amphoteric? |
The formula weight of $\ce CuSO_4 $ is 159.609 g/mole, that of $\ce CuSO_4 \cdot 5H_2O $ is 249.685 g/mole and the molecular weight of $\ce H_2O $ is 18.015 g/mole. So suppose you have two 500 mL beakers and you put 200.0 mL of water in each one. To the first beaker, add 15.9609 g of $\ce CuSO_4 $ and 9.008 g of water.... |
When you study the electronegativity of the elements, the general trend is that it rises with increasing group number, and decreasing period.
Supposedly this is because the attractive forces of the nucleus increase quicker than the shielding effect of the electrons.
1. Is this shielding effect simply a repellant ... |
I need to draw the Lewis formula for $\ce{CN}$. However, I am not sure how to draw the single free electron.
My idea would be as follows:
[![CN-Molecule][1]][1]
[1]: https://i.stack.imgur.com/rZHvi.png
Does that make sense? |
The formula weight of $\ce{CuSO4}$ is 159.609 g/mol, that of $\ce{CuSO4 . 5 H2O}$ is 249.685 g/mol and the molecular weight of $\ce{H2O}$ is 18.015 g/mol. So suppose you have two 500 mL beakers and you put 200.0 mL of water in each one. To the first beaker, add 15.9609 g of $\ce{CuSO4}$ and 9.008 g of water. Stir until... |
I need to draw the Lewis formula for $\ce{CN}$. However, I am not sure how to draw the single free electron.
My idea would be as follows:
$$\Large\ce{\llap{·}C#N\rlap{:}}$$
Does that make sense? |
I am confused about the structure of bridging complexes with the bridging ligands as OH- or NH2-. Aren't they both monodentate ligands? and if they form a simple co-ordinate bond, then the negative charge on them must be lost, but then the oxidation states of the metal atoms doesn't match.
For example,
[![Tetraaqua... |
Why different unit symbols - amu, u and dalton are used for representing atomic mass? And what does the term 'unified' mean in "unified mass unit"?
Thank you. |
Why the term 'unified' in "unified mass unit"? |
There is a question in my organic chemistry textbook with its answer. What it doesn't explain (and neither does my theory textbook, I checked) is the mechanism involved in the reaction. The reaction is as follows:
4-pentenoic acid + I(2) + CH(3)CN = 4-iodomethyl-4-Butyrolactone (?)
I'll try to add a photo.[![enter im... |
could someone explain to me the mechanism behind this organic chemical reaction? |
I am having some trouble figuring out how this reaction proceeds:
[![Reaction of (S)-cyclohex-3-ene-1-carboxylic acid to form (1S,5S)-6-oxabicyclo[3.2.1]oct-3-en-7-one][1]][1]
Attempt 1: The most obvious thing to do is deprotonate the acid group. I tried using the carboxylate group to attack the alkene, leaving t... |
I am confused about the structure of bridging complexes with the bridging ligands as $\ce{OH-}$ or $\ce{NH2-}.$ Aren't they both monodentate ligands?
And if they form a simple coordinate bond, then the negative charge on them must be lost, but then the oxidation states of the metal atoms doesn't match. For example:
... |
The main question is that is scopolamine extracted from datura or Brugmansia scopolamine freebase or scopolamine hydrobromide?
It is extracted via methanol or acetone from leaves and Seeds of Brugmansia or datura.
|
Is scopolamine same as scopolamine hydrobromide? |
There is a question in my organic chemistry textbook with an answer. What it doesn't explain (and neither does my theory textbook, I checked) is the mechanism involved in the reaction. The reaction is as follows:
[![synthesis of 5‐(iodomethyl)oxolan‐2‐one][1]][1]
Can someone help me?
[1]: https://i.stack.... |
I find myself in quite a pinch: I have to sustain a Chemical Physics exam, and I know for a fact that the professor often asks this particular question:
> Suppose that we have both a reacting species and an inhibitor in a homogeneous solution, and we insert a solid catalyst in it. What is the equation that describes... |
While writing [this answer](https://earthscience.stackexchange.com/a/17447/6031) to the question *Transmitter receiver coil separation for Electromagnetic Terrain Conductivity Measurement* I ran across this large PDF file of a book [Soil and Environmental Analysis; Physical Methods](http://base.dnsgb.com.ua/files/book/... |
Does water really have strong EM absorption at 3 kHz in solid and 2 GHz in liquid? Why the huge shift? |
Phys.org's [Giant lasers crystallize water with shockwaves, revealing the atomic structure of superionic ice](https://phys.org/news/2019-05-giant-lasers-crystallize-shockwaves-revealing.html) links to
- Nature Physics: [Experimental evidence for superionic water ice using shock compression](https://www.nature.com/... |
The Gizmodo article [Insane Light System Blasts the Energy of 10,000 Suns][1] and Phys.org's [Let there be light: German scientists test 'artificial sun'][2] both describe the large, powerful concentrated light source called *Synlight* which has been built by the German Aerospace Center (DLR).
This large (~350 kW!) ... |
Need help understanding impact of temperature and content of water/glycol on strength (crush, attrition) of methocel (methyl cellulose) extrudates.
In a given process, methocel is mixed at 150oF at 2wt% with a sand-water mixture (50:50) and 2% glycol. The mixture is then dried to extrudable moisture (20-30%) and e... |
Relevance
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During my Bachelor's project I focused on the synthesis of iron(II) complexes comprising a tetrapligand from the ligand family $\text{PY5R}_2\ (\text{R = H, Me, OH, OMe})$. [1-4] This ligand consists of one axial pyridine unit and four equatorial pyridine units. I investigated the activity of thes... |
Relevance
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During my Bachelor's project I focused on the synthesis of iron(II) complexes comprising a tetrapodal pentadentate ligand from the ligand family $\text{PY5R}_2\ (\text{R = H, Me, OH, OMe})$. [1-4] This ligand consists of one axial pyridine unit and four equatorial pyridine units. I investigated th... |
Sodium carbonate is used in pools to raise pH. From my understanding, it would dissociate in water like so.
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/J2f4L.png
To raise pH, doesn't it have to absorb hydrogen ion/s? If so then wouldn't it just form carbonic acid that would then ... |
How does sodium carbonate reduce pH? |
Sodium carbonate is used in pools to raise pH. From my understanding, it would dissociate in water like so:
$$\ce{Na2CO3 <=> 2 Na+ + CO3^2-}$$
To raise pH, doesn't it have to absorb hydrogen ion/s? If so then wouldn't it just form carbonic acid that would then just dissociate again? |
What makes the first 3 alkanes decrease in melting point (m.p.) while after that they rise?
$$
\begin{array}{lr}
\hline
\text{Alkane} & \text{m.p.}/\pu{°C} \\
\hline
\text{Methane} & -182 \\
\text{Ethane} & -183 \\
\text{Propane} & -188 \\
\text{Butane} & -138 \\
\text{Pentane} & -130 \\
\text{Hexane} &... |
The main question is that is scopolamine extracted from datura or Brugmansia scopolamine freebase or scopolamine hydrobromide?
It is extracted via methanol or acetone from leaves and Seeds of Brugmansia or datura.
If you take a look at the Wikipedia page for hyoscine. In synonyms part it says scopolamine hydrobro... |
Is scopolamine extracted with methanol or acetone from *Datura* or *Brugmansia* scopolamine free base or scopolamine hydrobromide?
If you take a look at the [Wikipedia page for hyoscine](https://en.wikipedia.org/wiki/Hyoscine), the *Synonyms* part lists scopolamine hydrobromide as a synonym for hyoscine even though ... |
This is the exact question I faced on an exam.
Calculate the pH of $\pu{0.05 M}\ \ce{Na2CO3}\ (\ce{H2CO3}: K_\mathrm{a,1}= 4\times 10^{-7},\ K_\mathrm{a,2}= 4.7\times 10^{-11})$
###Solution###
$$\ce{Na2CO3 ->2Na+ + CO3^2-}$$
I suppose nothing that can contribute to the pH of a solution happens to $\ce{Na+}$ i... |
These things are given to me in an excersice.
N2 + 3 F2 -----> 2NF3. (Enthalpy change= -263kJmol-1 )
The bond dissociation enthalpies of the Nitrogen triple bond and Nitrogen Flourine bond are given as 946kJmol-1 and 272kJmol-1.
I have to find the bond dissociation enthalpy of the F-F bond.
The given answers are... |
> $$\ce{N2 + 3 F2 -> 2 NF3} \quad ΔH = \pu{-263 kJ mol-1}$$
> The bond dissociation enthalpies of the nitrogen triple bond and nitrogen–flourine bond are $\pu{946 kJ mol-1}$ and $\pu{272 kJ mol-1}.$
Find the bond dissociation enthalpy of the $\ce{F-F}$ bond.
> **A**. $\pu{-423 kJ mol-1}$
> **B**. $\pu{-393 kJ... |
I have a 1mm thick plastic sheet, the plastic is not opaque.
Some gas pockets, I would say some *bubbles*, are inside the sheet; the size of the bubbles is about 1mm.
What methods are available to know the composition of the gas that is inside the pockets?
|
How can I know the composition of a gas pocket entrapped in a plastic sheet? |
If you can't wrap your head around getting the answer directly, just calculate the enthalpy of reaction for the two bond dissociation energies you are considering.
**Assume bond dissociation energy is 141 kJ/mol**
$$\Delta H_r = \pu{946 kJ/mol} + 3 \cdot \pu{141 kJ/mol} - 6 \cdot \pu{272 kJ/mol} = \text{negative... |
I have a 1mm thick plastic sheet, the plastic is not opaque.
Some gas pockets, I would say some *bubbles*, are inside the sheet; the size of the bubbles is about 1mm.
What methods are available to know the composition of the gas that is inside the pockets?
Methods can destroy the sample.
|
In an electrolytic cell, where the electrolysis of dilute sulfuric acid is taking place, would the rate of electrolysis be constant always, even at the beginning?
By rate of electrolysis, I mean the rate of gas production or the rate of charge delivery. And would this rate be established as soon as I turn on the vol... |
**IUPAC definition**
The [IUPAC definition][1] is the following:
> 1. The complete, net removal of one or more electrons from a molecular entity (also called 'de-electronation').
2. An increase in the oxidation number of any atom within any substrate.
3. Gain of oxygen and/or loss of hydrogen of an organic subs... |
**IUPAC definition**
The [IUPAC definition][1] is the following:
> 1. The complete, net removal of one or more electrons from a molecular entity (also called 'de-electronation').
2. An increase in the oxidation number of any atom within any substrate.
3. Gain of oxygen and/or loss of hydrogen of an organic subs... |
Typically, when a cathode and anode are inserted into a solution that allows current to flow, the ions are moving with a certain kinetic energy.
If the ions were to gain kinetic energy (through transfer of thermal energy for example), will more current be able to flow, and will the potential difference increase?
... |
Chemistry of Aromaticity. What's non hückel double bond ?
What are the difference between hückel and non-hückel double bond ?
[ Here, in figure the green one is non hückel double bond ] |
What is non-hückel double bond of Aromaticity? |
Why do we use $\bar{G}$ as a notation for partial molar free energy? |
I have a 1 mm thick plastic sheet, the plastic is not opaque.
Some gas pockets, I would say some *bubbles*, are inside the sheet; the size of the bubbles is about 1 mm.
What methods are available to know the composition of the gas that is inside the pockets?
Methods can destroy the sample.
|
In the question, I broke all the place where there is double and added a -CHO group as asked in the question (Ozonolysis)
And then checking for the optically active compounds I found 2 of them.
But the solution has given only 1 compound! Can ... |
I wanted to figure out a way to make calcium metal with potassium oxide. The K2O undergoes disproportionation at 350-430 degrees celsius: 2K2O = K2O2 + 2K.
Now, if I mixed in CaO (1:1 molar ratio with K2O) it would react with the potassium formed in the first reaction, forming calcium metal and K2O that would feed ba... |
What would be the products in this system? |
For the customs of ChemSE, the question is rather broad; perhaps even *too broad* to provide you specific compositions, times and temperatures to improve your process of producing extrudates.
On the other hand, you already collected a number of *plausible parameters* influencing the *target property*, which you name... |
What would be the concentration of products in this calcium producing system? |
I wanted to figure out a way to make calcium metal with potassium oxide. The K2O undergoes disproportionation at 350-430 degrees celsius: 2K2O = K2O2 + 2K.
Now, if I mixed in CaO (2:1 molar ratio with K2O) it would react with the potassium formed in the first reaction, forming calcium metal and K2O that would feed ba... |
I wanted to figure out a way to make calcium metal with potassium oxide. The K2O undergoes disproportionation at 350-430 degrees celsius: 2K2O = K2O2 + 2K.
Now, if I mixed in CaO (1:2 molar ratio with K2O) it would react with the potassium formed in the first reaction, forming calcium metal and K2O that would feed ba... |
Relevance
---------
During my Bachelor's project I focused on the synthesis of iron(II) complexes comprising a tetrapodal pentadentate ligand from the ligand family $\text{PY5R}_2\ (\text{R = H, Me, OH, OMe})$. [1-4] This ligand consists of one axial pyridine unit and four equatorial pyridine units. I investigated th... |
I am concentrating sulphuric acid. What should I use as boiling chips? I have tried broken mug pieces, the solution became cloudy, and I have tried broken glass (retrieved from a drinking class, not crystal) and the solution became yellow. |
What element emits the least light or radiation when heated to its highest vapor pressure point in a vacuum?
Ideally I would like to know in 0 gravity and 0 pressure which elements can be get the hottest around the sun before the vapor pressure point is reached and/or emit the least black body radiation when hot. ... |
What element with a high vapor point the emits to least light or radiation when heated to its vapor pressure point in a vacuum?
Ideally I would like to know in 0 gravity and 0 pressure which elements can be get the hottest around the sun before the vapor pressure point is reached and/or emit the least black body r... |
So I have a question that sounds:
A $SO_3$ molecule is radiated with light with a wavelenght of 193 nm, which results in photodissociation.
$SO_3+photon(\lambda=193nm)\rightarrow SO_2+O$
It is measured that the $SO_2$ fragment is in the electronic ground state, but in the vibrational excited state where bendin... |
>A $\ce{SO_3}$ molecule is radiated with light with a wavelenght of 193 nm, which results in photodissociation.
>$\ce{SO_3}+ \text{photon}(\lambda=\pu{193nm})\ce{\rightarrow SO_2+ O}$
>It is measured that the $SO_2$ fragment is in the electronic ground state, but in the vibrational excited state where bending ... |
>A $\ce{SO3}$ molecule is radiated with light with a wavelength of $\pu{193 nm}$, which results in photodissociation.
>$\ce{SO3} + \text{photon}(\lambda=\pu{193nm})\ce{-> SO2 + O}$
>It is measured that the $\ce{SO2}$ fragment is in the electronic ground state, but in the vibrational excited state where bending ... |
I’m not a chemist, but a software engineer. I’m trying to build a device that could detect if someone is burning trash (mostly plastics and similar materials) vs wood or diesel. At my disposal I have the following sensors: https://www.mysensors.org/build/gas
What sensor or combination of them would be most reliable ... |
I am doing an Organic Chem Project for school in the form of an acid base extraction of tolterodine tartrate (Detrol) in Ammonium Hydroxide (or Sodium Hydroxide, havent decided yet) and dissolving the freebase in benzene.
I am planning on crushing up the tablets, and dissolving them in water. Almost all the inactiv... |
Why do we use Ḡ ("G bar") as a notation for partial molar free energy? |
I am doing an organic chemistry project for school in the form of an acid-base extraction of tolterodine tartrate (Detrol) in ammonium hydroxide (or sodium hydroxide, haven't decided yet) and dissolving the freebase in benzene.
I am planning on crushing up the tablets, and dissolving them in water. Almost all the i... |
> The number of optically active compound(s) obtained upon complete ozonolysis of
the following optically active compound is
> [![(1E,3R,4Z,6S,7E,10S,11Z,13S)-3,6,10,13-tetramethylcyclotetradeca-1,4,7,11-tetraene][1]][1]
In the question, I broke all the double bonds and added a $\ce{-CHO}$ group according to the... |
Hydrogen iodide (HI) is a much larger molecule than chlorine (Cl₂), and it has a dipole. Hydrogen iodide's melting point (222.35 K) is definitely above chlorine's (171.6 K). However, hydrogen iodide's boiling point (237.79 K) is less than chlorine gas's (239.11 K).
This is very confusing, since Hydrogen Iodide h... |
Why does silicon tetrafluoride have a higher melting point than sulfur tetrafluoride? |
I need help understanding the physics behind [this insightful comment](https://chemistry.stackexchange.com/questions/118003/does-water-really-have-strong-em-absorption-at-3-khz-in-solid-and-2-ghz-in-liqui?noredirect=1#comment223943_118003) below the question [Does water really have strong EM absorption at 3 kHz in soli... |
Difference between a relaxation spectrum and an absorption line spectrum? |
I need help understanding the physics behind [this insightful comment](https://chemistry.stackexchange.com/questions/118003/does-water-really-have-strong-em-absorption-at-3-khz-in-solid-and-2-ghz-in-liqui?noredirect=1#comment223943_118003) below the question [Does water really have strong EM absorption at 3 kHz in soli... |
Difference between relaxation and resonance leading to an absorption spectral feature? |
I need help understanding the physics behind [this insightful comment](https://chemistry.stackexchange.com/questions/118003/does-water-really-have-strong-em-absorption-at-3-khz-in-solid-and-2-ghz-in-liqui?noredirect=1#comment223943_118003) below the question [Does water really have strong EM absorption at 3 kHz in soli... |
Why is triatomic hydrogen relatively short-lasting? |
What will the electronic configuration of La+ be? |
This is a partial answer. The typical gas sensor marketed to hobbyists and enthusiasts (except for $\ce{CO2}$) are of the metal oxide semiconductor type, *not to be confused with* MOS as in [MOSFET](https://en.wikipedia.org/wiki/MOSFET).
In these detectors, a semiconductor material made of the oxide of a metal, usua... |
The typical gas sensor marketed to hobbyists and enthusiasts (except for $\ce{CO2}$) are of the metal oxide semiconductor type, *not to be confused with* MOS as in [MOSFET](https://en.wikipedia.org/wiki/MOSFET).
In these detectors, a semiconductor material made of the oxide of a metal, usually tin.
I'll quote fro... |
The typical gas sensor marketed to hobbyists and enthusiasts (except for $\ce{CO2}$) are of the metal oxide semiconductor type, *not to be confused with* MOS as in [MOSFET](https://en.wikipedia.org/wiki/MOSFET).
How do these work?
--
In these detectors, a semiconductor material made of the oxide of a metal, usua... |
The typical gas sensor marketed to hobbyists and enthusiasts (except for $\ce{CO2}$) are of the metal oxide semiconductor type, *not to be confused with* MOS as in [MOSFET](https://en.wikipedia.org/wiki/MOSFET).
How do these work?
--
In these detectors, a semiconductor material made of the oxide of a metal, usua... |
What is the electronic configuration of La+? |
Is it safe to treat Platinum-carbon catalyst in an autoclave at 200 C for 24 hr? If no, can you suggest safety measures? |
For a gas having molar mass M, express specific heat at constant pressure in terms of heat capacity ratio.
My attempt:
using $ C_p - C_v = R $ and
$ \dfrac{C_p}{C_v} = \gamma $
$ C_p = \dfrac{R \gamma }{ \gamma - 1} $
But answer is
$ C_p = \dfrac{R \gamma }{ M(\gamma - 1)} $
But from where thi... |
> For a gas having molar mass $M$, express specific heat at constant pressure in terms of heat capacity ratio.
My attempt:
using $ C_p - C_V = R $ and
$ \dfrac{C_p}{C_V} = \gamma $
$ C_p = \dfrac{R \gamma }{ \gamma - 1} $
But answer is
$ C_p = \dfrac{R \gamma }{ M(\gamma - 1)} $
But from where... |
> The standard hydrogen electrode potential by conventional at 298 K is taken to be 0.00 volts.
This is what I have been taught. It talks about SHE at 298 K , so is the hydrogen electrode potential at a temperature other than 298 Kelvin also defined to be zero ?? If not how do we calculate at any other temperature ?? |
Is the Standard hydrogen electrode potential at T other than 298K also zero? |
How do we predict the products formed when we heat cyclic dicarboxylic acids? I know that in case of aliphatic dicarboxylic acids we apply Blanc's rule and predict the product formed based on the number of carbons between the acid groups.
In case of aliphatic dicarboxylic acids, when
1.n=0 ; product - Oxalic acid
... |
How do we predict the products formed when we heat cyclic dicarboxylic acids? I know that in case of aliphatic dicarboxylic acids we apply Blanc's rule and predict the product formed based on the number of carbons between the acid groups.
In case of aliphatic dicarboxylic acids, when
1.n=0 ; product - Oxalic acid
... |
T l, Dr: despite what you see from the aqueous electromotive series, potassium **does not** reduce calcium oxide in this setting.
You may be assuming that potassium, which lies above calcium in the electromotive series for aqueous solutions, therefore lies above calcium in all other settings regardless of chemical ... |
I would like to create an illustration to demonstrate something during a talk. The idea goes that there is sediment in a bottle of water that sits at the bottom until shaken up then adding another substance to the water makes the sediment dissolve or appear to vanish.
My question is; What would make this possible? ... |
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