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The choice to use wavenumbers for infrared spectroscopy (rather than wavelengths, frequencies, or energies) was probably done to provide a range that has both the appearance of width (so that the difference between two peaks is more meaningful) and spans a set of reasonable values that do not contain very large or very... |
While studying the [lamba sensor][1] that works on yttria-strabilised-zirconium (YSZ) I came across the following equation:
$$p_{O_2}^{gas}=p_{O_2}^{ref} \cdot \exp\left(\frac{4FV_{ref}}{RT}\right)$$
**What is $F$ in this equation?**
---
*Some more info*
The "wall" of the lambda sensor is as shown in the... |
This is an interesting question and you raise a number of points, let's step through them.
> A consequence of this is that relative atomic masses of elements
> mined—those with two or more stable isotopes—will no longer be
> faithful to our current periodic table.
But this is already happening. $\ce{^235U}$ co... |
Approximately 99.3% of uranium on Earth is the [$\mathrm{^{238}U}$ isotope](http://en.wikipedia.org/wiki/Uranium-238), and this specific isotope has an atomic mass of $\mathrm{238.05\ u}$, where $\mathrm{u}$ is the [atomic mass unit](http://en.wikipedia.org/wiki/Atomic_mass_unit), equivalent to 1/12 the mass of a $\mat... |
Approximately 99.3% of uranium on Earth is the [$\mathrm{^{238}U}$ isotope](http://en.wikipedia.org/wiki/Uranium-238), and this specific isotope has an atomic mass of $\mathrm{238.05\ u}$, where $\mathrm{u}$ is the [atomic mass unit](http://en.wikipedia.org/wiki/Atomic_mass_unit), equivalent to 1/12 the mass of a $\mat... |
I have created a firefly jar with glow sticks to sell at a school fair. The firefly jar lasts only for an hour or so. I have heard that glow sticks can be reactivate d. the firefly jars contain the chemical found in good sticks. Is there any way to make the jar glow again ? |
How hormone levels are measured exactly? |
Are there softeners used in polyester or polypropylene to make these materials more flexible? Or is this not needed for this kind of synthetics? |
Softeners in synthetic materials? |
Shakashiri describes the reaction of solid Ammonium Thiocyanate and solid Barium Hydroxide Octahydrate resulting in an endothermic reaction leading to subzero temperatures. I've performed this experiment and measured temperature as low as about $-10\ ^\circ\text{C}$.
Are there known chemical reactions that can lead ... |
I have created a firefly jar with glow sticks to sell at a school fair. The firefly jar lasts only for an hour or so. I have heard that glow sticks can be reactivated. The firefly jars contain the chemicals found in good sticks. Is there any way to make the jar glow again? |
Can I reactivate a chemoluminescent reaction? |
i just want know what particle in plants that can changes H2O into O2 and what CO2 do in this converting system, what if we just H2O and light to convert it into O2? and also about the reaction, if Lights the one that we need to convert CO2 into glucosa and H2O into oxygen, why scientist can't make a machine to convert... |
Any quantum number that represents the size of an orbital is a positive integer, $n$.
Any quantum number that represents the shape of an orbital is a non-negative integer, $l : l < n$.
Any quantum number that represents the orientation of an orbital, $m$, is an integer such that $|m| \leq l$.
Why do $n$ and... |
What is the mechanism of photosynthesis? |
Quantum numbers give information about the location of an electron or set of electrons. A full set of quantum numbers describes a unique electron for a particular atom.
Think about it as the mailing address to your house. It allows one to pinpoint your exact location out of a set of $n$ locations you could possi... |
**Can a flame a start on a wet piece of paper immersed in water?**
The video is shown below (not the full video):
https://youtu.be/Ey3z8z4Hxtc?t=1h27m29s
This is not in English so you might not understand anything. In the video they simply say it is demons or whatever that starts the fire, which is silly to m... |
Can a flame start on water (video included)? |
LiBr Vp chart:
http://www.mediafire.com/view/x77zc8wj11gthsj/LiBr_Vp.jpg
or
http://www.mediafire.com/view/u4dnocvbsf3atmu/Useful_Chart_LiBr.pdf
Lecture in question (p.13)
http://www.mediafire.com/view/gly78yz339hv1x1/RAC_Lecture_15.pdf
![enter image description here][1]
In the lecture it says that ... |
I'm trying to figure out how exactly does the silver start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how i see the nucleation/growth process of silver on silica:
Now, as ... |
How does the silver nucleate on glass in Tollen's reagent mirroring? |
The product of $2Z$ generally approximates the $m_\mathrm{a}$ of atoms that comprise relatively few protons. Whereas, the product of $2.5Z$ generally approximates the $m_\mathrm{a}$ of atoms that comprise relatively many protons. The product $((2+2.5)/2)Z$ generally approximates atoms that comprise a moderate number of... |
I'm trying to figure out how exactly does the silver start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how I see the nucleation/growth process of silver on silica:
Now, a... |
I'm trying to figure out how exactly does the silver start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how i see the nucleation/growth process of silver on silica:
Now, as ... |
I'm trying to figure out how exactly does the silver start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how i see the nucleation/growth process of silver on silica:
Now, a... |
I just want to know what particle in plants can change H2O into O2 and what CO2 does in this converting system. What if we just use H2O and light to convert it into O2? If light is what we need to convert CO2 into glucose and H2O into oxygen, why scientist can't make a machine to convert that? |
I just want to know what particle in plants can change $\ce{H2O}$ into $\ce{O2}$ and what $\ce{CO2}$ does in this converting system. What if we just use $\ce{H2O}$ and light to convert it into $\ce{O2}$? If light is what we need to convert $\ce{CO2}$ into glucose and $\ce{H2O}$ into oxygen, why scientist can't make a ... |
Are there softeners used in polyester or polypropylene to make these materials more flexible? Or is this not needed for this kind of synthesis? |
**The short answer is that you can find a cubic fit with relatively low average error.**
I'd never really thought about it much, but after downloading the [IUPAC Atomic Weights](http://www.ciaaw.org/atomic-weights.htm), I decided to do some curve fitting.
Here's a linear fit between atomic number and atomic mass:... |
The product of $2Z$ generally approximates the value of $m_\mathrm{a}$ of atoms that comprise relatively few protons. Whereas, the product of $2.5Z$ generally approximates the value of $m_\mathrm{a}$ of atoms that comprise relatively many protons. The product of $((2+2.5)/2)Z$ generally approximates the value of $m_\ma... |
Is there a function to approximate atomic mass from the atomic number? |
**The short answer is that you can find a power-law fit with low average error.**
I'd never really thought about it much, but after downloading the [IUPAC Atomic Weights](http://www.ciaaw.org/atomic-weights.htm), I decided to do some curve fitting.
Here's a linear fit between atomic number and atomic mass:
, I decided to do some curve fitting.
Here's a linear fit between atomic number and ato... |
Because of the 8-valence electron rule I assume in CO the left resonance structure to be favored .
$$\ce{:\!\overset{\ominus}{C}#\overset{\oplus}{O}\!: ~<->~ :\!C=O\!:: ~<->~:\!\overset{\oplus}{C}-\overset{\ominus}{O}\!:::}$$
(from http://chemistry.stackexchange.com/questions/25126/what-is-the-lewis-structure-fo... |
Can I predict the preferred resonance structure of carbon dioxide from its molecular orbital scheme? |
Can I predict the preferred resonance structure of carbon monoxide from its molecular orbital scheme? |
Because of the 8-valence electron rule I assume in CO the left resonance structure to be favored .
$$\ce{:\!\overset{\ominus}{C}#\overset{\oplus}{O}\!: ~<->~ :\!C=O\!:: ~<->~:\!\overset{\oplus}{C}-\overset{\ominus}{O}\!:::}$$
(from http://chemistry.stackexchange.com/questions/25126/what-is-the-lewis-structure-fo... |
Because of the 8-valence electron rule I assume in CO the left resonance structure to be favored .
$$\ce{:\!\overset{\ominus}{C}#\overset{\oplus}{O}\!: ~<->~ :\!C=O\!:: ~<->~:\!\overset{\oplus}{C}-\overset{\ominus}{O}\!:::}$$
(from http://chemistry.stackexchange.com/questions/25126/what-is-the-lewis-structure-fo... |
The choice to use wavenumbers for infrared spectroscopy (rather than wavelengths, frequencies, or energies) was probably done to provide a range that has both the appearance of width (so that the difference between two peaks is more meaningful) and spans a set of reasonable values that do not contain very large or very... |
In a study of the creation of ionic bonds of in this case $\text{Na}^+$ and $\text{Cl}^-$ into $\text{NaCl}$, I have come across this equation for the overall energy of the system:
$$E=-\frac{e^2}{4\pi\epsilon_0 R}+\frac{B}{R^n}+1.4 \,\mathrm{eV}$$
$e$: electron charge. $\epsilon_0$: vacuum permittivity. $R$: the... |
What are B and n in this expression for charge repulsion? |
In a study of the creation of ionic bonds of in this case $\ce{Na}^+$ and $\ce{Cl}^-$ into $\ce{NaCl}$, I have come across this equation for the overall energy of the system:
$$E=-\frac{e^2}{4\pi\epsilon_0 R}+\frac{B}{R^n}+1.4 \,\mathrm{eV}$$
$e$: electron charge. $\epsilon_0$: vacuum permittivity. $R$: the dista... |
I am refluxing $\ce{HBr}$ with 1,6-hexanediol for 16 hours at $80\ ^\circ\mathrm{C}$ in toluene. How can I be sure that more than $90\,\%$ of the product is brominated only at one terminal? If the amount of double brominated product is in more than $10\,\%$ of the total yield, then the product mixture will be useless f... |
I'm trying to figure out how exactly does the silver start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how i see the nucleation/growth process of silver on silica:
Now, a... |
Why are there more fluoride compounds formed with Xenon? |
$\ce{LiBr}$ $Vp$ chart:
http://www.mediafire.com/view/x77zc8wj11gthsj/LiBr_Vp.jpg
or
http://www.mediafire.com/view/u4dnocvbsf3atmu/Useful_Chart_LiBr.pdf
Lecture in question (p.13)
http://www.mediafire.com/view/gly78yz339hv1x1/RAC_Lecture_15.pdf
![enter image description here][1]
In the lecture it s... |
I wonder what compounds are usually called "ice" and what properties do determine it?
I can bring some examples of ice and not.
Not ice:
* H2S
* cellulose
* sugar
* graphite
* lithium
* solid mercury
* polyvinylchloride
* solid fats
* ...
Known as ices:
* solid water
* solid CO2
* solid nitroge... |
What properties a compound should have to be called an "ice"? |
I wonder what compounds are usually called "ice" and what properties do determine it?
I can bring some examples of ice and not.
Not ice:
* $\ce{H2S}$
* cellulose
* sugar
* graphite
* lithium
* solid mercury
* polyvinylchloride
* solid fats
* ...
Known as ices:
* solid water
* solid $\ce{CO2}$
*... |
I wonder what compounds are usually called "ice" and what properties do determine it?
I can bring some examples of ice and not.
Not ice:
* $\ce{H2S}$
* cellulose
* sugar
* graphite
* lithium
* solid mercury
* polyvinylchloride
* solid fats
* ...
Known as ices:
* solid water
* solid $\ce{CO2}$
*... |
The d-block sub-shell is always one shell lower than the s-block and p-block sub-shells. Assuming only the electrons in the highest energy shells count toward the set of valence electrons (is that correct?), d-block is never in the highest energy shell, and so none of the electrons in the d subshells would ever count t... |
Is d-block ever part of the valence electrons? |
I am trying to understand why 1,2- and 1,3-dichlorobenzenes are such good solvents, able to solvate many organic compounds known to be hard to get dissolved.
Any precise answer ???
It has something to do with dipolar moment and Hansen's diffusion parameter I think.
Cheers |
How are hormone levels measured? |
Potassium comprises 19 protons and 18 core electrons. Those electrons screen 18 protons worth of Coulomb force. Therefore, there is one proton worth of Coulomb force attracting the valence electron of potassium. Whereas, krypton comprises 36 protons and 28 core electrons. Its electrons screen 28 protons wroth of Coulom... |
Do I understand why the atomic radius of Kr is smaller than the atomic radius of K? |
I am trying to understand why 1,2- and 1,3-dichlorobenzenes are such good solvents, able to solvate many organic compounds known to be hard to get dissolved.
Any precise answer?
It has something to do with dipolar moment and Hansen's diffusion parameter I think.
|
The $d$-block sub-shell is always one shell lower than the $s$-block and $p$-block sub-shells. Assuming only the electrons in the highest energy shells count toward the set of valence electrons (is that correct?), $d$-block is never in the highest energy shell, and so none of the electrons in the $d$ subshells would ev... |
I have been searching for the mechanism of the Mozingo reduction on google but I haven't managed to find it.
Is it known ? If so, what is it; if not, what hypothetical mechanisms have we considered ? |
Potassium comprises 19 protons and 18 core electrons. Those electrons screen 18 protons worth of Coulomb force. Therefore, there is one proton worth of Coulomb force attracting the valence electron of potassium.
Whereas, krypton comprises 36 protons and 28 core electrons. Its electrons screen 28 protons wroth of Co... |
To the best of my knowledge, the following properties affect atomic radius.
1. The grounded-state size of the valence electron shell.
2. The Coulomb force of the core electrons less the Coulomb force of the protons.
3. The number of electrons in the valence shell.
4. Whether an electron#-proton# imbalance i... |
Is there an algorithm for ascertaining the relative size of an atomic/ionic radius? |
Looking at this equation pH = pKa +log[CB/A] makes me think that it is concentration independent.
What I mean is, when we look at [CB/A], the volumes cancels out, so we are only left with the molar ratio of the conjugate acid and conjugate base. So does this mean that the pH is only dependent on the molar ratios? Ob... |
Is the Henderson Hasselbalch equation volume independent? |
Looking at this equation $\ce{pH = pK_{a} +log[\frac{CB}{A}]}$ makes me think that it is concentration independent.
What I mean is, when we look at $[\frac{CB}{A}]$, the volumes cancels out, so we are only left with the molar ratio of the conjugate acid and conjugate base. So does this mean that the pH is only depen... |
On the favoured Lewis structures
----
Well yes, you have correctly drawn a minus sign next to the oxygen in the rightmost structure and similarly a plus sign next to the oxygen in the leftmost structure. However, *these are not true charges!* These are **formal charges**. They can be representative of real charges ... |
To the best of my knowledge, the following properties affect atomic radius.
1. The grounded-state size of the valence electron shell.
2. The Coulomb force of the core electrons less the Coulomb force of the protons.
3. The number of electrons in the valence shell.
4. Whether an electron#-proton# imbalance i... |
How do we prepare potassium cyanide from potassium ferrocyanide?
It is something which I am curious about, but cannot find the answer. I am studying inorganic chemistry but this reaction cannot be found. |
I was wondering if it would be possible to use HCl acid to dissolve PbS.
I know that I can dissolve it in $HNO_3$ since, the nitric acid oxidises the sulphide ion to elemental sulphur, and some sulphides like ZnS do dissolve in HCl. But what about PbS? What is the extent of pH sensitivity of lead sulphide precipitate. |
I was wondering if it would be possible to use $\ce{HCl}$ acid to dissolve $\ce{PbS}$.
I know that I can dissolve it in $\ce{HNO_3}$ since, the nitric acid oxidises the sulphide ion to elemental sulphur, and some sulphides like $\ce{ZnS}$ do dissolve in $\ce{HCl}$. But what about $\ce{PbS}$?
What is the extent... |
How do we prepare potassium cyanide from potassium ferrocyanide?
It is something which I am curious about, but cannot find the answer. I am studying inorganic chemistry but this reaction cannot be found.thanks in advance |
How do we prepare potassium cyanide from potassium ferrocyanide?
It is something which I am curious about, but cannot find the answer. I am studying inorganic chemistry but this reaction cannot be found. |
23. A galvanic cell consists of a standard hydrogen electrode and a copper electrode. Suppose that the copper electrode is immersed in a solution that is 0.100 M in NaOH and that is saturated with Cu(OH)2. Find Cell potential
2 H+ (aq) → H2 (g) EO = 0.00 V
Cu2+ (aq) + 2e- → Cu (s) EO = 0.34 V
... |
> A galvanic cell consists of a standard hydrogen electrode and a copper
> electrode. Suppose that the copper electrode is immersed in a
> solution that is $0.100 \ce{M}$ in $\ce{NaOH}$ and that is saturated
> with $\ce{Cu(OH)2}$. Find cell potential
>
> $\ce{2 H+ (aq) → H2 (g)}$ $E_O = 0.00 V$
>
> $\ce{C... |
> A galvanic cell consists of a standard hydrogen electrode and a copper
> electrode. Suppose that the copper electrode is immersed in a
> solution that is $0.100\ \mathrm{M}$ in $\ce{NaOH}$ and that is saturated
> with $\ce{Cu(OH)2}$. Find cell potential
>
> $\begin{alignat}{2}\ce{2 H+ (aq) -> H2 (g)}\quad E_0 ... |
Looking at this equation $\mathrm{pH} = \mathrm{p}K_\text{a} +\log\frac{[\ce{CB}]}{[\ce{A}]}$ makes me think that it is concentration independent.
What I mean is, when we look at $\frac{[\ce{CB}]}{[\ce{A}]}$, the volumes cancels out, so we are only left with the molar ratio of the conjugate acid and conjugate base. ... |
Is the Henderson–Hasselbalch equation volume independent? |
I read that continuum in line spectra is noticed beyond a certain limit. What does it mean? |
What is continuum in line spectra? |
On my studies i have a group project to realise: to make some Ag nanoparticles using Turkevich method (boiling AgNO3 with sodium citrate in water). In most of articles authors write about using sodium citrate solution, but when I search for this compound on sigma-aldrich they offer me a wide range of compounds named "s... |
Which sodium citrate is used in silver nanoparticles production? |
In my studies, I have a group project to realise: to make some $\ce{Ag}$ nanoparticles using Turkevich method (boiling $\ce{AgNO3}$ with sodium citrate in water). In most of articles authors write about using sodium citrate solution, but when I searched for this compound on Sigma-Aldrich, they offer me a wide range of ... |
I recently read somewhere that electrons does not exist its just the electron density. Is it true that there are no such electrons (particles) but only form electron density ? And does this contradict the fact of dual nature of electron. |
Does electron really exist? |
When I read heading I thought it is general question for which 1 answer is okay. But when I read **200 litres** I thought I will dig out a bit and write few more stuff.
I found few related question on [Methanol Institute](http://www.methanol.org/health-and-safety/frequently-asked-questions.aspx)
****
>What kin... |
I recently read somewhere that electrons do not exist. it's just the electron density. Is it true that there are no electrons (particles) but only in the form of electron density? And does this contradict the fact of dual nature of electron? |
Do electron really exist? |
My teacher told me that lone pair and lone pair are closer together hence the repulsion is greater and they take up more space but i do not understand? can anyone explain it to me? |
My teacher told me that lone pair and lone pair are closer together hence the repulsion is greater and they take up more space, but I do not understand? can anyone explain it to me? |
Why do lone pair- lone pair have more repulsion compared to lone-bond and bond-bond pairs? |
![Qualitative Analysis of Anions][1]
From the image above, if you all could take a loot at step **1a**. It makes no sense to me. I do not understand why adding $\ce{HC3COOH}$ has any effect on the solution whatsoever. What is the point of adding it when we later add $\ce{HNO3}$?
[1]: https://i.stack.imgur.com/I... |
![Qualitative Analysis of Anions][1]
From the image above, if you all could take a loot at step **1a**. It makes no sense to me. I do not understand why adding $\ce{HC3COOH}$ has any effect on the solution whatsoever. What is the point of adding it when we later add $\ce{HNO3}$?
**EDIT:** Just looked at the questio... |
I'm reading the chapter on gases in Chang/Overby's book "General Chemistry: The Essential Concepts", and the following passage is causing me some confusion:
![enter image description here][1]
I don't quite understand the underlined sentence; in particular, I don't understand how the underlined claim "follows" fro... |
What is flavanoid physical and chemical properties, and how alkaline reagent test for flavonoids gives yellow coulour? |
When one say that the electron goes from 1 orbit , say <i><b>2<sub>S</sub></i></b>, to another (higher) orbital, say <i><b>5<sub>P</sub></b></i>, it mean that the electron is excited to that orbit by some mean. In doing so it also it will also cross the nodes of <I><B>2<SUB>P</sub></b></i> etc. But doing so does the el... |
electron passing nodes? |
From this [reference][1]:
> Treatment of a flavonoid with a strong base will result in ionization of its hydroxyl groups with resulting large bathochromic shifts of both absorption maxima.
[1]: https://books.google.com/books?id=TXsiFVVuCqMC&pg=PA203&lpg=PA203&dq=flavonoid%20base&source=bl&ots=04L0QuwFfy&sig=x... |
![Qualitative Analysis of Anions][1]
From the image above, if you all could take a loot at step **1a**. It makes no sense to me. I do not understand why adding $\ce{CH3COOH}$ has any effect on the solution whatsoever. What is the point of adding it when we later add $\ce{HNO3}$?
**EDIT:** Just looked at the questio... |
Why does the current increase over time in an electrolytic cell with a $\ce{CuNO3}$ electrolyte. The current increased about $2~\mathrm{A}$, and the temperature increased during the experiment to around $55\ \mathrm{^\circ C}$.
I’m not sure whether the formation of hydrogen and oxygen gas at the electrodes would de... |
What is the difference between *crystal radius* and *ionic radius*? For NaCl for example the ions combine to a crystal, and I would have guessed they are equal. But I then found an example of data, where they are not.
I am aware that [ionic radius][1] is the radius of an atom's ion. Quite simple. So what is *crystal... |
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