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Why must the total increase in oxidation numbers equal the total decrease of them? |
In my book, under the topic of redox reactions, it is given,
> In all redox reactions, the total increase in oxidation number must be equal to the total decrease in oxidation number.
Is this a consequence of "Charges can never be created. The total charge of a system remains constant", or something else?
For t... |
Which is more basic: oxaziridine or diaziridine?
[![oxaziridine and diaziridine][1]][1]
Oxaziridine's got one nitrogen and one oxygen as heteroatoms, while in diaziridine there are both nitrogens.
[1]: https://i.stack.imgur.com/EU2OS.png |
Which is more basic: oxaziridine or diaziridine? |
The activation energy is **not** the av.kinetic energy that the colliding particles need in order to successfully react.
To describe the rate of a reaction there are two models:
<br> The Arrhenius model and the more sophisticate Eyring model. The Arrhenius model uses the activation energy, defined as the energy re... |
Why must the total increase in oxidation numbers equal the total decrease of them in redox reactions? |
I read an [article](https://www.popsci.com/turning-methane-into-carbon/) by popsci that talked about huge fans forcing methane over a catalyst.
Now that got me wondering, can't we produce hydroxyl radicals with powerfull uv lasers blasting the sky, creating more hydroxyl radicals to break down the methane.
Would ... |
I've read about the ideal gas law and the van der Waal's gas law. I know that the ideal gas law is horribly inaccurate for temperatures close to, but above the critical temperatures, so it can only be used for permanent gases like nitrogen, oxygen, etc. The van der Waal's equation is a little better in this regard, but... |
Is there a decent way to test for solvable manganese in water without purchasing a 150USD test kit? I have a fair chemistry set available (I use it to teach my kids chemistry), and would rather pay 50USD for something to add to it that can also be used for other things later than pay for some test that may not be that ... |
Are there other mixtures than piranha solution with similiar or better ability to completely and readily oxidize organic matter? Perhaps peracetic/performic acid? |
To complement @blu_potatos's answer, there are some other contenders having refractive index greater than 2
1. **Arsenic di/trisulfide and sulfur and/or selenium and/or mercuric sulfide in arsenic tribromide solvent** having refractive index ranging from 2.0 to 2.0 (arsenic tribromide seem to attack the lead-glass ... |
In particular, if I cut a block of stainless steel in half, would the newly formed faces be stainless as well? |
Is "stainless" a bulk or a surface property of stainless steel? |
The roots of this question comes from [this previous question][1](marked unclear). I don't know about the context of that question but I was intrigued by a statement in that question:
> Superphosphate is used instead of just phosphate because
> superphosphate is a compound whereas phosphate is an ion.
Now, the ... |
What is "super" in superphosphate? |
In [this][1] Wikipedia link about the excited states of oxygen, this diagram is shown. [![enter image description here][2]][2] The left most molecular orbital diagram is the first excited state of oxygen, and the MO diagram in the middle is the second excited state of oxygen. It seems to imply that the energy of pairin... |
We all could know by now that water can be electrolysed by adding some sulfuric acid.:)
But is it possible that the sulfuric acid itself becomes electrolysed when the concentration of the acid in the water gets higher ?
Would it give sulfur dioxide or sulfur trioxide ? |
Can sulfuric acid itself be electrolysed? |
This question is inspired from a [previous question][1](marked unclear). I don't know about the context of that question but I was intrigued by a statement in that question:
> Superphosphate is used instead of just phosphate because
> superphosphate is a compound whereas phosphate is an ion.
Now, the question i... |
After some searching, I found [this 1956 paper][1] which describes the production of peroxydisulfuric by electrolyzing concentrated sulfuric acid. The yield varied according to the concentration of the acid, temperature, current and the nature of the electrode. In the paper, the chemists noted that dischared $\ce{HSO4-... |
After some searching, I found [this 1956 Thesis][1](Reference), which describes the production of peroxydisulfuric by electrolyzing concentrated sulfuric acid. The yield varied according to the concentration of the acid, temperature, current, and the nature of the electrode. In the Thesis, the chemist noted that discha... |
There are *many, many dozens* of substances and mixtures that can readily oxidize organic matter, in some cases explosively. The degree of completeness of the oxidation process is dependent on the specific circumstances, e.g., is the organic matter sucrose or a piece of wood?
That said, a few notable oxidizing subst... |
The conjugation properties of cyclopropane are subject of debate. You can find a blog about this on the royal society of chemistry website(http://my.rsc.org/blogs/84/1009).
I have found an interesting paper in ref.1 and according to this:
>In one chemical attempt to test the transmission
of conjugation by cyclopro... |
The conjugation properties of cyclopropane are subject of debate. You can find a blog about this on the royal society of chemistry website(http://my.rsc.org/blogs/84/1009).
I have found an interesting paper in ref.1 and according to this:
>In one chemical attempt to test the transmission
of conjugation by cyclopro... |
The average wavenumber for a ketone is about 1720 cm-1 and the average wavenumber for an ester is about 1740 cm-1. This, however, does not make sense, as the carbonyl group of an ester should have a greater single bond character than the ketone due to resonance from the adjacent oxygen atom. This greater single bond ch... |
Why do Ketones Have Lower Wavenumbers than Esters? |
About the molecule that you remember cited in your textbook, there's a study in ref.1. According to these authors:
[![enter image description here][1]][1]
>The delocalization of the C1-C2 and Cl-C3 electrons of spiro[2.4]hepta-4,6-diene (1a) and partial rehybridization at C1, C2, and C3
result in a contributing ... |
The average wavenumber for a ketone is about $\pu{1720 cm-1}$ and the average wavenumber for an ester is about $\pu{1740 cm-1}$. This, however, does not make sense, as the carbonyl group of an ester should have a greater single bond character than the ketone due to resonance from the adjacent oxygen atom. This greater ... |
I have read some other posts explaining what multi-reference and multi-configuration are with regards to the wave-function (such as [this post](https://chemistry.stackexchange.com/questions/103387/what-exactly-is-meant-by-multi-configurational-and-multireference)).
However, what does it mean for a molecule specific... |
What is meant when people say a molecule has high multi-reference character? |
What Is The Heat Of Combustion Of Diesel And How Do I Find It? |
[![enter image description here][1]][1]
[![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/XkttM.png
[2]: https://i.stack.imgur.com/1e2vR.png
The question is asking which reagents can be used to carry out this reaction. I get the L (PCC) is used to turn the primary alcohol into an ... |
Why is potassium tertbutoxide not used to deprotonate the tertiary alcohol? |
Since a destructive method is allowed, the other suggestions did not work for you (despite being excellent, especially the Archimede's scales suggested by @porphyrin) and you have hot caustic soda (aka $\ce{NaOH}$), I suggest this plausible method (which, thankfully, I have never had to use). First, crush a small amoun... |
I'm a high school student considering the concentration of solutions, and whether the concentration is constant at the bottom or towards the surface. Even then, how would I know that the solution is consistent and not more concentrated in places compared to others? Is there any visual way or method for identifying non-... |
This question is inspired from a [previous question][1](marked unclear). I don't know about the context of that question but I was intrigued by a statement in that question:
> Superphosphate is used instead of just phosphate because
> superphosphate is a compound whereas phosphate is an ion.
Now, the question i... |
To complement @blu_potatos's answer, there are some other contenders having refractive index greater than 2
1. **Arsenic di/trisulfide and sulfur and/or selenium and/or mercuric sulfide in arsenic tribromide solvent** having refractive index ranging from 2.0 to 2.07 (arsenic tribromide seem to attack the lead-glass... |
This question is inspired from a [previous question][1](marked unclear). I don't know about the context of that question but I was intrigued by a statement in that question:
> Superphosphate is used instead of just phosphate because
> superphosphate is a compound whereas phosphate is an ion.
Now, the question is... |
While dealing with the Lewis structure for ozone, most of the explanations, show the electron distribution around the 3 oxygen atoms with a single and double bond.
But if you count the number of valence electrons of the middle oxygen atom, it will add to 5 valence electrons only, but the number of valence electrons... |
While dealing with the Lewis structure for ozone, most of the explanations show the electron distribution around the 3 oxygen atoms with a single and double bond.
But if you count the number of valence electrons of the middle oxygen atom, it will add to 5 valence electrons only, but the number of valence electrons ... |
Consider the hydrogen atom for simplicity.
The electronic density at the nucleus is not null.
The attractive potential between a small volume of electronic density $dV$ (at position $\vec r$) and the nucleus (at position $\vec R$) is:
$\frac{-Z*\rho(\vec r)}{|\vec R - \vec r|}dV$
How is the energy not going... |
Consider the hydrogen atom for simplicity.
The electronic density at the nucleus is not null.
The attractive potential between a small volume of electronic density $\mathrm dV$ (at position $\vec r$) and the nucleus (at position $\vec R$) is:
$$\frac{-Z\rho(\vec r)}{|\vec R - \vec r|}\mathrm dV$$
How is the... |
[![circuit and potencials schematic - potentiostat (3 electrode system)][1]][1]
[1]: https://i.stack.imgur.com/vAiG8.jpg
I'm an electronic engineer student and I'm trying to understand the basics of electrolytic cells and practical values' meaning. Based on my figure and electrode potencial values (Vce, Vre a... |
Why does indolizine undergo EAS on C3 and not C5 of the pyrrole ring? |
Using Slaters rule, I found that both Lead and Tin’s $Z_{eff}$ for $6p$ and $5p$ electrons equal, however, the Ionisation Energy is different. Is comparing Ionisation Enthalpy on the basis of $Z_{eff}$ not correct? Also, I found [Clementi-Raimondi Effective Nuclear Charge][1] which probably explains the trend, but why ... |
Why is Leads first Ionisation Enthalpy greater than that of Tin? |
Using Slater's rule, I found that both lead and tin's $Z_\mathrm{eff}$ for 6p and 5p electrons equal. However, the ionisation energy is different. Is comparing ionisation enthalpy on the basis of $Z_\mathrm{eff}$ not correct?
Also, I found [Clementi-Raimondi Effective Nuclear Charge][1] which probably explains the ... |
Why is leads first ionisation enthalpy greater than that of tin? |
As part of my PhD project I'm currently looking into running a Shi Epoxidation reaction. The first step is to reproduce the current literature on this reaction by using trans-stilbene as my substrate. However, from the multitude of reaction conditions I have tried, none of them seem to work as described in the papers (... |
[![circuit and potentials schematic - potentiostat (3 electrode system)][1]][1]
[1]: https://i.stack.imgur.com/vAiG8.jpg
I'm an electronic engineer student and I'm trying to understand the basics of electrolytic cells and practical values' meaning. Based on my figure and electrode potencial values (Vce, Vre a... |
----------
# 1/ The iodine method:
----------
I found the answer on [this video][1] (from Cody's lab youtube channel). Cody's show how to make activated carbon/charcoal and how to test it's efficiency.
It's quite simple actually. The test below measures the absorption's efficiency of your filter/charcoal... |
In the redox titration:
$$\ce{MnO4- + 8 H+ + 5 Fe^2+ -> Mn^2+ + 4 H2O + 5 Fe^3+}$$
the colour change which occurs is purple to colourless, because of the decreased concentration of permanganate ions. But doesn't this fail to account for the visible iron ions? $\ce{Fe^2+(aq)}$ is green and $\ce{Fe^3+(aq)}$ is brow... |
For the 4th option:-
Will it be like the following?
X'- + XX'(n) = XX'(n+1) Something like this? (X and X' are halogen compounds)
So the polyhalide ion here would be X'(n+1).
What would be you views on this? |
Every 4.5V lantern batteries are a series of three 1.5V cells. It would have more capacity if it consisted of single 4.5V cell. But I don't see any 4.5V cell.
According to Wikipedia's [Standard Electrode Potential][1] data page, there are vast possibilities of a 4.5V cell. The one I think most plausible is:
A... |
Why doesn't anyone manufacture 4.5V cells? |
Every 4.5V lantern batteries are a series of three 1.5V cells. It would have more capacity if it consisted of single 4.5V cell. But I don't see any 4.5V cell.
According to Wikipedia's [Standard Electrode Potential][1] data page, there are vast possibilities of a 4.5V cell. The one I think most plausible is:
> Anod... |
You are running an ICP, with bracketing standards of 10 ppm(mg/L) K+ and 100 ppm K+ and sample of 500 ppm, prepared 5 mL diluted to 100 mL. Shouldn’t you adjust your upper limit bracketing standard, instead of just diluting your sample? Your original sample concentration of K+ (500 ppm) should not change adjusted for t... |
> Interhalogen compounds are formed when two halogens $(\ce{F},$ $\ce{Cl},$ $\ce{Br},$ $\ce{I})$ react together. They are represented by $\ce{XX'_n},$ where $\ce{X}$ is halogen of larger size and $\ce{X'}$ of smaller size. The total number of halogens in $\ce{XX'_n}$ depends on the radii of $\ce{X}$ and $\ce{X'}.$ The ... |
Can you give examples for a halide ion reacting with interhalogen compound to give polyhalides? |
For an application I need a commercial, transparent liquid with refractive index $n>2$.
1. Is this kind of liquid available?
2. What's the chemical composition of this?
On the web, only $n=1.81$ is routine. |
Every 4.5V lantern batteries are a series of three 1.5V cells. It would have more capacity if it consisted of single 4.5V cell. But I don't see any 4.5V cell.
According to Wikipedia's [Standard Electrode Potential][1] data page, there are vast possibilities of a 4.5V cell. The one I think most plausible is:
> Anod... |
How to derive this temperature-pressure-specific volume relationship? |
Every 4.5 V lantern batteries are a series of three 1.5 V cells. It would have more capacity if it consisted of single 4.5 V cell. But I don't see any 4.5 V cell.
According to Wikipedia's [Standard Electrode Potential][1] data page, there are vast possibilities of a 4.5 V cell. The one I think most plausible is:
... |
Why doesn't anyone manufacture 4.5 V cells? |
The problem asks to determine the $[\ce{H+}]$ in a $0.20~\mathrm{M}$ solution of $\ce{Na3PO4}$. The $K_\mathrm{a}$ of $\ce{HPO4-}$ was given as $4.5\times 10^{-13}$, which then allows one to calculate the corresponding $K_\mathrm{b}$ as $2.22\times10^{-2}$.
As any acid-base problem, I simply set up the expression $\... |
Why is lead's first ionisation enthalpy greater than that of tin? |
As Ed said you are following the correct protocol by diluting the sample. The key reason is for doing so is to avoid a non-linear region in the calibration curve. This is why one would dilute the sample rather than make more concentrated standards. Several interesting effects happen with alkali metals at high concentra... |
You are running an ICP-MS (Inductively coupled plasma mass spectrometry), with bracketing standards of 10 ppm(mg/L) K<sup>+</sup> and 100 ppm K<sup>+</sup> and sample of 500 ppm, prepared 5 mL diluted to 100 mL. Shouldn’t you adjust your upper limit bracketing standard, instead of just diluting your sample? Your origin... |
I encountered many questions in the competitive exam field of high school organic chemistry where we add some compounds and treat it in excess alcohol solutions in the presence of dry hcl gas, it is obvious how the mechanisms might go if the hcl is in liquid solution but when i see dry hcl gas i have no idea how it mig... |
Based on the OP’s two questions and the OP’s several comments, the OP wants to know if there is a commercially available liquid which, at 23°C, is transparent in the range 380 to 700 nm. As the OP stated in a comment, the liquid should be “not poisonous and can be used as gap fillers in refractometers (gap between pris... |
As part of my PhD project, I'm currently looking into running a Shi Epoxidation reaction. The first step is to reproduce the current literature on this reaction by using *trans*-stilbene as my substrate. However, from the multitude of reaction conditions I have tried, none of them seem to work as described in the paper... |
Definition of refractive index:
$n=\frac {c}{v}$
If n>2 then this means that the velocity of light in the material is less than half than in vacuum so there must be a strong interaction with the material.
<br> One of the highest refractory index in liquids is 1.79(20°C) possessed by a solution of sulfur in met... |
Based on the OP’s two questions and the OP’s several comments, the OP wants to know if there is a commercially available liquid which, at 23°C, is transparent in the range 380 to 700 nm. As the OP stated in a comment, the liquid should be “not poisonous and can be used as gap fillers in refractometers (gap between pris... |
Definition of refractive index:
$n=\frac {c}{v}$
If n>2 then this means that the velocity of light in the material is less than half than in vacuum so there must be a strong interaction with the material.
<br> One of the highest refractory index in liquids is 1.79(20°C) possessed by a solution of sulfur in met... |
I'm trying to figure out what terms are possible for nitrogen with the electron configuration $[He]2s^22p^3$. There is an [old question][1] on StackExchange and the corresponding answer was a great help already but doesn't mention J or specify what terms exactly are possible. I'll try to explain how I would determine t... |
I'm trying to figure out what terms are possible for nitrogen with the electron configuration $\ce{[He] 2s^2 2p^3}$. There is an [old question][1] on StackExchange and the corresponding answer was a great help already but doesn't mention $J$ or specify what terms exactly are possible. I'll try to explain how I would de... |
When a vitamin or supplement claims, for example, that it contains
> 600 mg of calcium (as calcium carbonate)
what does that mean? Does each tablet contain 600 milligrams of the element calcium?
Or does a tablet contain 600 milligrams of the compound calcium carbonate? In that case, using the molar masse... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/EYHsa.png
I realize that one of the methyl groups on either carbonyl compound will become deprotonated and then it will attack the other carbonyl to form a pentane ring. However, with the methyl group in the picture below there should be a... |
I need some information of bonding energy.
I found that the bonding energy of I2 is 151 kJ/mol (https://www.chegg.com/homework-help/dimethyl-ether-ch3och3-ethanol-ch3ch2oh-constitutional-isome-chapter-9-problem-90p-solution-9781259631757-exc)
but I have some difficulty in searching the bonding energy of I3-.
Would... |
what is the bonding energy of I2 and I3-? |
Your problem seems to be with the terminology used in CI methods, so let me go through the different terms you mentioned:
- A **configuration** is a certain occupation of (molecular) orbitals. Mathematically configurations can be represented in 2 ways. The first one is the **Slater Determinant** (SD), an anti-symmet... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/6mWfi.jpg
why is this not named as 4-bromo-6-methoxyphenol? Shouldn't the substituents be named according to their alphabetical order? |
why is this not named as 4-bromo-6-methoxyphenol? shouldn't the substituents be named according to their alphabetical order? |
"The vapour pressure of water at 80° C is 355 torr. A 100 mL vessel contained water-saturated oxygen at 80° C, the total gas pressure being 760 torr. The contents of the vessel were pumped into a 50 mL vessel at the same temperature. What were the partial pressures of oxygen and of water vapour, what was the total pres... |
According to bents rule in pentagonal bipyramidal more electronegative element is placed on the axial position ...so between Cl and Och3 which should be placed on axial as oxygen is more electronegative but ch3 would reduce it's overall electronegativity due to its +I effect...but my teacher said that Och3 should still... |
Which substitutent should be placed on axial position? |
> Name the compound:
> [![Halogen-substituted ethane][1]][1]
How should I name this? 1,1,1-tribromo-2,2-dichloroethane or 2,2,2-tribromo-1,1-dichloroethane?
[1]: https://i.stack.imgur.com/3zD88.png |
I am quoting a rule on resonance from **Organic Chemistry ,T.W. GRAHAM SOLOMONS , CRAIG B. FRYHLE**, 12th edition , page number 25.
>3. Structures in which all the atoms have a complete valence shell of electrons
(i.e., the noble gas structure) are more stable.
I tried to apply to the following.
[![enter image ... |
Which of the resonance structures is more stable? |
It is known that the order of leaving group favourability of the halide ions changes when we go from nucleophilic substitution, in the form of $
\ce {S_N1}$ and $\ce {S_N2}$ reactions, to nucleophilic aromatic substitution reactions ($\ce {S_NAr}$). In the former, the primary consideration is the strength of the $\ce ... |
It is known that the order of leaving group favourability of the halide ions changes when we go from nucleophilic substitution, in the form of $
\ce {S_N1}$ and $\ce {S_N2}$ reactions, to nucleophilic aromatic substitution reactions ($\ce {S_NAr}$). In the former, the primary consideration is the strength of the $\ce ... |
I am quoting a rule on resonance from *Organic Chemistry* by T.W. Graham Solomons, Craig B. Fryhle, 12th edition, page 25.
> 3. Structures in which all the atoms have a complete valence shell of electrons
(i.e., the noble gas structure) are more stable.
I tried to apply to the following.
[![enter image descript... |
[![Structure of 4-Bromo-2-methoxyphenol][1]][1]
[1]: https://i.stack.imgur.com/6mWfit.jpg
Why is this named as 4-Bromo-2-methoxyphenol and not 4-Bromo-6-methoxyphenol? Shouldn't the substituents be numbered according to their alphabetical order? |
See, there are few things you should keep in mind while deciding comparative stability of resonance structures:
Non-polar structures are more stable than dipolar.
Resonance structures with a greater number of covalent bonds are more stable than those with lesser number. Thus, nonpolar structure of buta-1,3-die... |
I am a 11th/12th grade student studying Orbital Configurations, and I have gone over this lesson. It says to always draw spin up first, but never says why. I am hoping to get a clear answer out of this, please and thank you? |
Is drawing down in a spin model incorrect? |
Provided that I know the enthalpy of formation $\Delta H_f^0(X_{g})$ of a substance $X$ in gas phase and its [enthalpy of dissolution][1] $\Delta H^0_{sol}(X)$ in the same conditions, considering that the dissolution reaction is $X_g \leftrightharpoons X_{aq}$
is it legit to consider that the enthalpy of formation of... |
[![Structure of 4-bromo-2-methoxyphenol][1]][1]
[1]: https://i.stack.imgur.com/6mWfit.jpg
Why is this named as 4-bromo-2-methoxyphenol and not 4-bromo-6-methoxyphenol? Shouldn't the substituents be numbered according to their alphabetical order? |
***"1 L of an aqueous solution of urea having density = 1.06 g/mL is found to have ΔTb (elevation in boiling point) = 0.5° C. If the temperature of this solution is increased to 101.5° C, then calculate the amount of water which must have vapourised by doing so. Kb (ebullioscopic constant) of water is given = 0.5 K Kg ... |
Let $\frac{h}{\pi}=\frac{nh}{2\pi}$
Therefore n=2
So $$E=\frac{-13.6}{4}=-3.4eV$$
The answer is -6.8eV. What’s wrong with my solution? (I think the issue is with the formula, yet I would like to confirm it) |
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