instruction stringlengths 15 21.8k |
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In an experiment, I gently heated iodine crystals to create vapors and then observed it absorption spectrum with a spectrometer. The temperatures throughout were moderate (maximum $40^\circ\text{C}$). I observed a series of dark bands from red region to blue-green region with spacing between consecutive bands decreasin... |
How to assign initial and final states of iodine transitions in its spectrum? |
What is the colour of FeS4O6 solution? |
Has a phase diagram for [hydrogen fluoride][1] been published on the internet or in a book ?
Or is there a table for HF for different pressures up to 100 atm. and temperatures up to 500$⁰$ C ?
[1]: https://en.wikipedia.org/wiki/Hydrogen_fluoride
|
Is there a phase diagram for hydrogen fluoride? |
Has a phase diagram for [hydrogen fluoride][1] been published in an article on the internet or in a book ?
Or is there a table for HF for different pressures up to 100 atm. and temperatures up to 500$⁰$ C ?
[1]: https://en.wikipedia.org/wiki/Hydrogen_fluoride
|
I really don’t understand why the following reaction would take place first of all.
[![enter image description here][1]][1]
So this is a sub part of a question wherein we have to compare the basicity of the compounds formed through some reactions. So, I got the rest 3 of them but I have no clue about this one.
... |
What is the colour of FeS4O6 solution?!
[![Question][1]][1]
[1]: https://i.stack.imgur.com/Fn7jx.jpg |
Has a phase diagram for [hydrogen fluoride][1] been published in an article on the internet or in a book ?
Or is there a table for HF for different pressures up to 100 atm. and temperatures up to 500$⁰$ C ?
Or, even better, is there a calculator for HF, like [this one for steam][2] ?
[1]: https://en.w... |
Is there a phase diagram available for hydrogen fluoride? |
This is a relativelt analytical chemistry question and it requires that you remember the color of all common transition metal ions and their very common precipitates. You have to remember the colors of halogens in solution as well.
Instead of worrying about the color of iron thiosulfate (which is bluish green), thin... |
This is a relatively advanced analytical chemistry question and it requires that you remember the color of all common transition metal ions and their very common precipitates. You have to remember the colors of halogens in solution as well.
Instead of worrying about the color of iron thiosulfate (which is bluish gre... |
The correct answer is, indeed, in my opinion choice (B) as is noted.
The action of KI on CuSO4 creates, in situ, the very unstable CuI2 (think of the corresponding salt with iron, Ferric iodide, whose very existence is doubted).
Per the [web from Wikipedia](https://www.google.com/search?q=wikipedia+on+CuI2&rlz=1... |
The correct answer is, indeed, in my opinion choice (B) as is noted.
The action of KI on CuSO4 creates, in situ, the very unstable CuI2 (think of the corresponding salt with iron, Ferric iodide, whose very existence is doubted).
Per the [web from Wikipedia](https://www.google.com/search?q=wikipedia+on+CuI2&rlz=1... |
The correct answer is, indeed, in my opinion choice (B) as is noted.
The action of KI on CuSO4 creates, in situ, the very unstable CuI2 (think of the corresponding salt with iron, Ferric iodide, whose very existence is doubted).
Per the [web from Wikipedia](https://www.google.com/search?q=wikipedia+on+CuI2&rlz=1... |
We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some difficulties regarding applying pressure and the make up of membranes . Given our unfavorable circumstances (low budget ,... |
We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some difficulties regarding applying pressure and the make up of membranes . Given our unfavorable circumstances (low budget ,... |
The action of HCl on Zn results in the formation of hydrogen.
Next, there is some surface chemistry where the diffusion of atomic hydrogen (or hydrogen radical) occurs with select metals. See, for example, this 2008 thesis ["Alkaline dissolution of aluminum: surface chemistry and subsurface interfacial phenomena"](... |
The action of HCl on Zn results in the formation of hydrogen.
Next, there is some surface chemistry where the diffusion of atomic hydrogen (or hydrogen radical) occurs with select metals. See, for example, this 2008 thesis ["Alkaline dissolution of aluminum: surface chemistry and subsurface interfacial phenomena"](... |
The action of HCl on Zn results in the formation of hydrogen.
Next, there is some surface chemistry where the diffusion of atomic hydrogen (or hydrogen radical) occurs with select metals. See, for example, this 2008 thesis ["Alkaline dissolution of aluminum: surface chemistry and subsurface interfacial phenomena"](... |
The action of HCl on Zn results in the formation of hydrogen.
Next, there is some surface chemistry where the diffusion of atomic hydrogen (or hydrogen radical) occurs with select metals. See, for example, this 2008 thesis ["Alkaline dissolution of aluminum: surface chemistry and subsurface interfacial phenomena"](... |
The action of HCl on Zn results in the formation of hydrogen.
Next, there is some surface chemistry where the diffusion of atomic hydrogen (or hydrogen radical) occurs with select metals. See, for example, this 2008 thesis ["Alkaline dissolution of aluminum: surface chemistry and subsurface interfacial phenomena"](... |
Why fibres are strong only in the direction they are oriented?Why they break if we pull at right angle to their orientation?
|
Why fibres are strong only in one direction? |
[Linde Gas](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.linde-gas.com/en/images/Linde%2520Anhydrous%2520Hydrogen%2520Fluoride%2520datasheet_tcm17-446018.pdf&ved=2ahUKEwjtg7exs7TnAhV8Ap0JHfPRAsEQFjAEegQIBhAB&usg=AOvVaw2GLDPwe7mPkMDSqxeuAbIx&cshid=1580699369850) contains a capor pressure curve. Note... |
Related to the problem of minimization of the Lennard-Jones potential in a molecule with $n$ atoms, where $n$ is, say, between $5$ and $10$, questions arise such as the following:
1. Is it possible to determine a lower bound on the radius of the molecule?
2. Is it possible to determine an upper bound on the radiu... |
Are there any theorems about packing of atoms in molecules subject to the Lennard-Jones potential? |
I've gotten really into this subject lately from people who make their own cleaning agents and I was surprised how simplistic (although time consuming) everything was.
I am interested in making slaked lime. I've been putting wood ashes in my garden bed lately and it's been doing wonders but if I had a steady supply ... |
The action of HCl on Zn results in the formation of hydrogen.
Next, there is some surface chemistry where the diffusion of atomic hydrogen (or hydrogen radical) occurs with select metals. See, for example, this 2008 thesis ["Alkaline dissolution of aluminum: surface chemistry and subsurface interfacial phenomena"](... |
Related to the problem of minimization of the Lennard-Jones potential in a molecule with $n$ atoms, where $n$ is, say, between $5$ and $10$, questions arise such as (but not limited to) the following:
1. Is it possible to determine a lower bound on the radius of the molecule?
2. Is it possible to determine an upp... |
Consider a solution of $\text{HCl}$ with a concentration of $10^{-10}$ $\text{M}$. Now, if I find it's pH:
$$\begin{aligned}\text{pH} &= -\log([\text{H}^+])\\
\text{pH} &= -\log(10^{-10}) = 10\end{aligned}$$
At room temperature, $\text{pH} + \text{pOH} = 14 \implies \text{pOH}$ of the given acid is $4$. This means t... |
I understand the basics of electrochemsitry and galvanic cell, where there are half cells where either an oxidation or reduction reaction occur, and electrons moving between the wires provide the current.
What confuses me is the salt bridge. In this diagram here, nitrate ions, which are from the solution of a half c... |
Do ions in a salt bridge come from the half cells in electrochemistry? |
In one of my classwork on the decomposition reaction of hydrogen peroxide by catalase, I wrote the following equation:
$$\ce{2H2O2 -> 2H2O + O2}$$
However, my teacher said that I should go further in depth and write down the (quote on quote) "mechanism" of this reaction. I'm not sure what he is talking about, can any... |
What is the "mechanism" of the decomposition of hydrogen peroxide? |
Why fibres are strong only in the direction they are oriented?Why they break if we pull at right angle to their orientation?
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/heREl.gif |
In my classwork on the decomposition reaction of hydrogen peroxide by catalase, I wrote the following equation:
$$\ce{2H2O2 -> 2H2O + O2}$$
However, my teacher said that I should go further in depth and write down the (quote unquote) "mechanism" of this reaction. I'm not sure what he is talking about, can anyone help... |
In my classwork on the decomposition reaction of hydrogen peroxide by catalase, I wrote the following equation:
$$\ce{2H2O2 -> 2H2O + O2}$$
However, my teacher said that I should go further in depth and write down the (quote unquote) "mechanism" of this reaction. I'm not sure what he is talking about, can anyone help... |
[Linde Gas](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.linde-gas.com/en/images/Linde%2520Anhydrous%2520Hydrogen%2520Fluoride%2520datasheet_tcm17-446018.pdf&ved=2ahUKEwjtg7exs7TnAhV8Ap0JHfPRAsEQFjAEegQIBhAB&usg=AOvVaw2GLDPwe7mPkMDSqxeuAbIx&cshid=1580699369850) contains a vapor pressure curve. Note... |
[Linde Gas](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.linde-gas.com/en/images/Linde%2520Anhydrous%2520Hydrogen%2520Fluoride%2520datasheet_tcm17-446018.pdf&ved=2ahUKEwjtg7exs7TnAhV8Ap0JHfPRAsEQFjAEegQIBhAB&usg=AOvVaw2GLDPwe7mPkMDSqxeuAbIx&cshid=1580699369850) contains a vapor pressure curve. Note... |
Why fibres are strong only in the direction they are oriented?Why they break if we pull at right angle to their orientation?
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/heREl.gif
Here each blue line represents combination of polymeric chains. |
I have a question regarding Nano coatings based on the formula "modified SiO2".
I have been told that Al bottles react with substances with a pH value below 3 or above 9. When the substances are not within these limits, it will form Al3+ which will cause the Al bottle to corrode, if i understand it correctly.
My... |
I have a question regarding nano coatings based on the formula "modified $\ce{SiO2}$".
I have been told that $\ce{Al}$ bottles react with substances with a $\mathrm{pH}$ value below 3 or above 9. When the substances are not within these limits, it will form $\ce{Al^3+}$ which will cause the $\ce{Al}$ bottle to corr... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
It seems intuitive to think that in a bottle (which is air-tight), if you fill up ethanol (or any other volatile liquid) to very full extent, thereby leaving very little headspace, evaporation of ethanol would be reduced. In contrast, if there is more headspace, then more room is allowed for ethanol vapor and hence eva... |
Is the evaporation (liquid to gas conversion) of ethanol dependent on how full you fill it up in a sealed bottle? |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminium resistance is related to the thin and compact layer of nat... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminum resistance is related to the thin and compact layer of natu... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminum resistance is related to the thin and compact layer of natu... |
consider this simple two step reaction, a variant of a michaelis-menten type of problem, where A and B reversibly bind to make AB, and AB and C reversibly bind to make ABC:
$A + B\ce{<=>} AB$
$AB + C\ce{<=>} ABC$
assume all the rate constants are equal to $k$ for simplicity, and that $A_0, B_0, C_0$ are initia... |
steady-state solution for simple two-step reaction with differential equations? |
> $15.0~\mathrm{mL}$ of $1.4~\mathrm{M}\ \ce{HCl}$ was mixed with $1.00~\mathrm{g}$ of limestone (impure $\ce{CaCO3}$) until all the solid had dissolved. The solution was then transferred to a conical flask and made up to $200~\mathrm{mL}$ with water. A $20.0~\mathrm{mL}$ portion was then neutralised by $8.50~\mathrm{m... |
It seems intuitive to think that in a bottle (which is air-tight), if you fill up ethanol (or any other volatile liquid) to very full extent, thereby leaving very little headspace, amount of ethanol evaporated would be reduced. In contrast, if there is more headspace, then more room is allowed for ethanol vapor and hen... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminum resistance is related to the thin and compact layer of natu... |
A cited a pH value below 3 or above 9 is in line with the usually citation for the stability of the Al2O3 protective layer. [Per a source](http://www.electrochemsci.org/papers/vol9/91005496.pd) on the effect of pH, to quote:
> It is well known that aluminum resistance is related to the thin and compact layer of natu... |
When welding on steel with a galvanized coating, hexavalent chromium is yielded from the chemical reaction. This gas is something that I would like to eliminate before I begin welding, possibly with some liquid or mixture. Any ideas? |
How can I eliminate the harmful gas produced from the heating/manipulation of galvanized steel? |
It seems intuitive to think that in a bottle (which is air-tight), if you fill up ethanol (or any other volatile liquid) to very full extent, thereby leaving very little headspace, the amount of ethanol evaporated would be reduced. In contrast, if there is more headspace, then more room is allowed for ethanol vapor and... |
My textbook says the following on viscosity and pressure:
> increase in pressure decreases the viscosity of water but for other liquids it increases. Viscosity of gases does not change much
No further explanation is provided.
I have two doubts regarding this:
1. How does the viscosity of water decrease? Does ... |
Density of water increases from 273 to 277 K due to increase in entropy? |
I understand the basics of electrochemsitry and galvanic cell, where there are half cells where either an oxidation or reduction reaction occur, and electrons moving between the wires provide the current.
What confuses me is the salt bridge. In this diagram here, nitrate ions, which are from the solution of a half c... |
The hydrolysis of Group-15 tetrahalides gives us their hydroxides via a $\ce{S_{N^2}}$ mechanism:
$$\ce{PCl3 + 3H2O -> H3PO3 + 3HCl}$$
Nitrogen Trichloride, however, yields a different set of products, not forming the trihydroxide as expected.
$$\ce{NCl3 + 3H2O -> NH3 + 3HOCl}$$
A little bit of research led me to... |
Why does N(OH)3 not exist? |
Well let's not focus on your text but on the actual question here about $\ce{N(OH)3}$.
I can only give you some ideas here but not a definite answer.
Whenever we have tests for our first semester students there are some who forgot what a nitrate was, or nitric acid. But as we ask for a nitrate as trivial name an o... |
As a non chemist I am always charmed when visiting Wikipedia articles of chemical elements and see images of very pure deposits of element after element, proton by proton and often also metal cube made from smithing similar deposits.
The wiki article [Periodic table][1] allows me to do so; here are some elements I f... |
How do chemists distinguish very pure chemical element deposits that look almost "the same"? |
As a non chemist I am always charmed when visiting Wikipedia articles of chemical elements and see images of very pure deposits of element after element, proton by proton and often also metal cube made from smithing similar deposits.
The wiki article [Periodic table][1] allows me to do so; here are some elements I f... |
As a non chemist I am always charmed when visiting Wikipedia articles of chemical elements and see images of very pure deposits of element after element, proton by proton and often also metal cube made from smithing similar deposits.
The wiki article [Periodic table][1] allows me to do so; here are some elements I f... |
I really don’t understand why the following reaction would take place first of all.
[![octahydroazecine][1]][1]
So this is a sub part of a question wherein we have to compare the basicity of the compounds formed through some reactions. So, I got the rest 3 of them but I have no clue about this one.
My concerns... |
As a non chemist I am always charmed when visiting Wikipedia articles of chemical elements and see images of very pure deposits of element after element, proton by proton and often also metal cube made from smithing similar deposits.
The wiki article [Periodic table][1] allows me to do so; here are some elements I f... |
How is red oxide of copper converted into black oxide & vice versa? |
>Between 1 and 2, 2 is more basic as the 3 methyl groups would produce a +I effect resulting in better availability of the lone pair than in option 2.
I agree that more methyl groups would result in a greater +I effect.
>But the book says it is 3. I don't understand why. I do make out that it is ionic, but how d... |
The solution is emerald green in colour.
When added with water, it gives a pale blue solution.
When reacted with $\ce{BaCl2}$, it gives a sky blue solution and a white precipitate.
When reacted with $\ce{AgNO3}$, it gives a sky blue solution and a white precipitate.
This does not make any sense to me. The $\c... |
How to identify an emerald green solution with possibly two anions? |
Calculate how many grams of *p*-nitrophenol are required to prepare $\pu{250 mL}$ of a $\pu{11 mM}$ solution. (Answer to 3 significant figures.)
I worked it out as
\begin{align}
\frac{250}{1000}\,\mathrm{L} \times (\pu{11E-3 M}) \times \pu{139.11 g//mol}
&= \pu{2.75E-3 mol} \times \pu{139.11 g//mol} \\
&=... |
How to round significant figures correctly? |
I am working on fabricating the icyball system. I am planning to charge it with the help of convex mirrors. Whether it is necessary to create a vaccum inside the refrigeration closed cylinders before filling ammonia? |
In rounding with significant figures, you want to avoid undue precision, yes, but it's also important to *minimize error*. It's this error minimization which is the primary goal of all "round to nearest" approaches.
So in short:
\begin{align}
0.383 - 0.3825525 &= 0.0004475\\
0.3825525 - 0.382 &= 0.0005525
\end... |
> For the reaction
$$ \ce{2N2O5(g) -> 4NO2 + O2(g)} $$
the rate law is:
$$ \frac{\mathrm{d}[\ce{O2}]}{\mathrm{d}t} = k[\ce{N2O5}] $$
At $\pu{300 K}$, the half-life is $\pu{2.50E4 s}$ and the activation energy is $\pu{103.3 kJ/mol}$.
What is the rate constant at $\pu{350 K}$?
I know there is something fishy a... |
How to calculate the rate constant at different temperature for the decomposition of dinitrogen pentoxide? |
> A quantity of benzene, $\ce{C6H6}$, and toluene, $\ce{C6H5CH3}$, is placed in a $\pu{1 L}$ evacuated vessel at $\pu{25 ^\circ C}$. At equilibrium, a small volume of liquid is visible at the bottom of the container. A sample of the vapour phase is analysed and found to contain $\pu{53 mol-\%}$ benzene.
What is the mo... |
Recently, I've read that when metals are exposed to a high voltage source, metals produce a spectrum. I am curious on what is the minimum value of that 'high voltage'? Is the spectrum due to the high voltage depends on the atomic properties of the metal? Any help is highly appreciated. Thank You. |
As per the title, really. I potentially need to protect a bit of pipework from hot oxygen (800-1000 K), and I've seen this refractory paint for sale. It says it's good up to 1750 C, but hot oxygen is another kettle of fish. I'd have thought since it's formed from oxides at high temperature and it doesn't lose any oxyge... |
Would Zirconium (IV) Silicate be stable in a hot oxygen atmosphere? |
Work so far:
Molality = mol solute/kg solvent
Molarity = mol solute/L solution
So for molarity to exceed molality in the same solution, the numerical value of
kg of solvent > L of solution
From my experience this never happens. However by applying this to a very dense solvent, could the mass of solvent ... |
> $15.0~\mathrm{mL}$ of $1.4~\mathrm{M}\ \ce{HCl}$ was mixed with $1.00~\mathrm{g}$ of limestone (impure $\ce{CaCO3}$) until all the solid had dissolved. The solution was then transferred to a conical flask and made up to $200~\mathrm{mL}$ with water. A $20.0~\mathrm{mL}$ portion was then neutralised by $8.50~\mathrm{m... |
We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some difficulties regarding applying pressure and the fabrication of membranes . Given our unfavorable circumstances (low budg... |
I am having a lot of trouble removing trace levels of solvent from an oily nonpolar organic compound. I have been using a rotary vacuum system to remove the nonpolar solvent. Solvent removal is the last step in a purification process that must yield USP grade product. The compound is heat sensitive and degrades easily ... |
What are methods for removing trace levels of solvent? |
Working on-board a research vessel somewhere at sea, you have (carefully) isolated 12.5 micrograms
(12.5 ×10–6 g) of what you hope is pure saxitoxin (a non-electrolyte) from a poisonous (and quite cross)
puffer fish. You dissolve this sample in 3.10 mL of water and determine that the osmotic pressure of
the resultin... |
In the Nile Red video [Making ferrofluid from scratch](https://youtu.be/6L8yUY-doNc) a suspension of small [magnetite](https://en.wikipedia.org/wiki/Magnetite) ($\ce{Fe^{2+}Fe_2^{3+}O_4^{2−}}$) particles is produced from a combination of ferrous chloride and ferric chloride.
The nanoparticles are then given a coatin... |
How to calculate how large the magnetite particles be in Nile Red's ferrofluid video could be? |
In the Nile Red video [Making ferrofluid from scratch](https://youtu.be/6L8yUY-doNc) a suspension of small [magnetite](https://en.wikipedia.org/wiki/Magnetite) ($\ce{Fe^{2+}Fe_2^{3+}O_4^{2−}}$) particles is produced from a combination of ferrous chloride and ferric chloride.
The nanoparticles are then given a coatin... |
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