instruction stringlengths 15 21.8k |
|---|
I understand that to separate molecules by HPLC (or SFC) you commonly adjust the pH of the mobile phase to get preferable charges (i.e. negative charges) on the molecules - so that they interact with the column and are therefore well separated and thus give a large distinct peak.
Im not completely sure I understand... |
Why can zwitterions be difficult detect by HPLC-MS? |
For the extraction of chromium, fusion of chromite ore with sodium or potassium carbonate in excess of air is done.
What exactly happens in this 'fusion' process?
source : ncert chemistry class 12 textbook , d- and f-block element, extraction of chromite ore |
How is the mixture composed? Find expressions for mass, volume and amount of substance.
\begin{align}
\tag1\label1
V_\text{total} &= V_{\ce{O2}} + V_{\ce{Ar}}\\
\tag3\label2
n_\text{total} &= n_{\ce{O2}} + n_{\ce{Ar}}\\
\tag3\label3
m_\text{total} &= m_{\ce{O2}} + m_{\ce{Ar}}
\end{align}
Transform ... |
How is the mixture composed? Find expressions for mass, volume and amount of substance.
\begin{align}
\tag1\label1
V_\text{total} &= V_{\ce{O2}} + V_{\ce{Ar}}\\
\tag3\label2
n_\text{total} &= n_{\ce{O2}} + n_{\ce{Ar}}\\
\tag3\label3
m_\text{total} &= m_{\ce{O2}} + m_{\ce{Ar}}
\end{align}
Transform ... |
Another visualization:
- Assume $\pu{19.3 g}$ of pure oxygen; use the ideal gas law to find the volume $V_1$
- Assume $\pu{19.3 g}$ of pure argon; use the ideal gas law to find the volume $V_2$, smaller than $V_1$ since argon is heavier than oxygen
- Hopefully, the actual volume will be somewhere in between ... |
I am parameterizing a force field and would need to obtain non-bonded interaction parameters of atoms (e.g., Lennard-Jones parameters).
My primary idea is to obtain a potential energy curve using the Gaussian 09 software and fit the data on that curve to an equation that has non-bonded interaction parameters of atom... |
I am looking to make metallic ink for inkjet printing and using PEO 1 wt% (MW ~600,000) as a binder. The print head I am hoping to use has a nozzle diameter of 80 microns. The metal powder dispersed in the ink is ~100nm. If I dissolve the PEO into deionized water, will the PEO particles be too big to pass through the ... |
Does PEO particle size decrease when dissolved in water? |
Why does $\ce{[Co(NO2)6]^4-}$ ion have 3 unpaired electron as opposed to 1?
The book says that it has 3 unpaired electrons. I thought $\ce{NO2-}$ was a strong field ligand, making $\ce{Co^2+}$ a $\ce{d^7}$ low spin ion. Six electrons go in the $\mathrm{t_{2g}}$ orbital and 1 in the $\mathrm{e_g}$ orbital.
Please ... |
I've measured the hydrodynamic thickness of a NaPSS layer on polystyrene latex and plotted it against the concentration of the supporting electrolyte, NaCl.
My graph shows a general decrease in thickness with some fluctuations at earlier concentrations. I thought that thickness would increase with concentration due to... |
hydrodynamic thickness of polymer vs. concentration of electrolyte? |
[![reaction equation][1]][1]
I believe that the first step is the Cannizzaro reaction which will give (c) as a product.
But since we are also adding $\ce{H+}$ in the second step, shouldn't an esterification reaction take place? That would give (d) as a final product.
However the answer given is (c).
My only g... |
Can I determine the rate law constant from stoichiometric coefficients? |
Can I determine the rate law order from stoichiometric coefficients? |
In the following question, the [water/wine mixing problem](https://en.wikipedia.org/wiki/Wine/water_mixing_problem) was recast in chemical terms. However, [partial molar volumes](https://en.wikipedia.org/wiki/Partial_molar_property) can make this a much more challenging problem than it appears on the surface.
https... |
In the following question, the [water/wine mixing problem](https://en.wikipedia.org/wiki/Wine/water_mixing_problem) was recast in chemical terms. However, [partial molar volumes](https://en.wikipedia.org/wiki/Partial_molar_property) can make this a much more challenging problem than it appears on the surface.
https... |
How is the mixture composed? Find expressions for mass, volume and amount of substance.
\begin{align}
\tag1\label1
V_\text{total} &= V_{\ce{O2}} + V_{\ce{Ar}}\\
\tag3\label2
n_\text{total} &= n_{\ce{O2}} + n_{\ce{Ar}}\\
\tag3\label3
m_\text{total} &= m_{\ce{O2}} + m_{\ce{Ar}}
\end{align}
Transform ... |
How is benzoic acid soluble in benzene. What causes the hydrogen and benzoate bond to break? Something is soluble in water because of hydration enthalpy of water but i can't understand what causes the solubility in benzene? |
**This is a quote from my textbook**:
>The irregular trend in the first ionisation enthalpy of 3d lmetals,can be accounted for by considering that the removal of one electron alters the relative energies of 4s and 3d orbitals. So the unipositive ions have dn configuration with no 4s electrons.There is thus a reorganiz... |
>A very large swimming pool filled with water of temperature equal to $20\ \mathrm{^\circ C}$ is heated
by a resistor with a heating power of $500\ \mathrm{W}$ for $20$ minutes. Assuming the water in the
pool is not in any contact with anything besides the resistor:
>Is the change of entropy of the resistor positi... |
I think the answer has to be no. The old fashioned name for lead acetate was ‘sugar of lead’. Poisonous though it is, it earned its deadly sweet name. As well, some salts of beryllium (all of which are highly poisonous) and yttrium are sweet tasting: see wiki. So it is not just various organic substances that can taste... |
In the painting ["Dream Caused by the Flight of a Bee"][1] by Salvador Dali, among other strange items, we may see a fish flying in midair. There is also one in the drawing ["Big Fish Eat Little Fish"][2] by Bruegel the Elder. One may conclude that there is a flying fish in _every_ picture out there. One may even publi... |
As asked by the OP, I think the answer to the question has to be no. If it was known that a drink contained only glucose as a sweetener, then it would presumably be possible to measure accurately the glucose concentration in the drink. But maybe other substances in the drink would be interferences in the measurement. F... |
I've had this doubt for quite a while, This link
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Map%3A_Physical_Chemistry_for_the_Biosciences_(Chang)/04%3A_The_Second_Law_of_Thermodynamics/4.08%3A_Dependence_of_Gibbs_Energy_on_Temperature_and_Pressure
Clearly states that G... |
Is Gibbs energy minimized for processes at constant temperature are pressure only? |
I'm currently working on a chemistry project in which I need to convert ethyl methyl carbonate to ethyl formate.
[![ethyl methyl carbonate ‐> ethyl formate][1]][1]
I only have a simple background in organic chemistry (and I haven't seen anything about reaction mechanisms yet), but I was guessing water could be u... |
How to convert an organic carbonate to its formate ester? |
As asked by the OP, I think the answer to the question has to be no. If it was known that a drink contained only glucose as a sweetener, then it would presumably be possible to measure accurately the glucose concentration in the drink. But maybe other substances in the drink would be interferences in the measurement. F... |
I'm currently working on a chemistry project in which I need to convert ethyl methyl carbonate to ethyl formate.
[![ethyl methyl carbonate ‐> ethyl formate][1]][1]
I only have a simple background in organic chemistry (and I haven't seen anything about reaction mechanisms yet), but I was guessing water could be u... |
I am parameterizing a force field and would need to obtain non-bonded interaction parameters of atoms (e.g., Lennard-Jones parameters).
My primary idea is to obtain a potential energy curve using the Gaussian 09 software and fit the data on that curve to an equation that has non-bonded interaction parameters of atom... |
I've had this doubt for quite a while, This link
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Map%3A_Physical_Chemistry_for_the_Biosciences_(Chang)/04%3A_The_Second_Law_of_Thermodynamics/4.08%3A_Dependence_of_Gibbs_Energy_on_Temperature_and_Pressure
Clearly states that G... |
> One of the following diastereomeric chlorides undergoes racemization on heating whilst the other is returned unchanged. Explain.
> [![enter image description here][1]][1]
From the reaction conditions I can see that there must be an elimination of $\ce{HCl}$, presumably via E2 with the base being the amine group... |
I read that a martensitic transformation can travel at the speed of sound in that material. Is that confirmed as being the fastest speed of a chemical reaction (transformation)? |
Is the speed of sound the fastest rate that a chemical reaction can progress through a substance? |
At the end of electronic configuration, we were taught that, electron orbitals are most stable when they are either fully filled or half filled.
E.g., the final valence configuration of chromium is $\ce{(4s)^1 (3d)^5}$ and not $\ce{(4s)^2 (3d)^4}$.
But the final electronic configuration of chlorine is $\ce{(3s)^2 (3... |
I've got a bottle of sodium hydride 60% dispersion in mineral oil. It's not "in mineral oil" it's just powder with an oil coating. I'm using it in an inert reaction, is there a way to remove the oil? |
> if I mix sugar in water, how can I test its level or number of sweetness?
Number of sweetness is perhaps subjective. However, sugar content can be measured by refractive index changes (if you are just talking about sugar and water and no colors). Refractive index linearly increases with sugar content in water.
... |
I have recently purchased a memory foam pillow and in two days i ve experienced breathing problems and stomach problems and eyes irritation due to the harsh toxins in it and I returned the memory foam. But, The memory foam has touched the walls next to the bed and the plywood on the bed. Because of which i m unable to ... |
I have read (thanks to stack exchange) that mixing water and Sulfuric acid is exothermic, as is NaOH and HCl.
Are there two 'safe' liquids that can be mixed and produce anywhere near the same amount of heat? By 'safe' I mean they don't come with the same heavy warnings as Sulfuric acid or Lye. I would like them to b... |
PdPS is being considered as a layered material but when I look at its crystal structure it does not look like that. Fo example I could not figure out its interlayer distance. Does anyone familiar with this structure? |
The **Redlich Peterson isotherm model** is known as:
$$
\begin{aligned}
q_e=\frac{AC_e}{1+BC^g_e}
\end{aligned}
$$
Is there any way to obtain the linear form of this equation by algebraic transformation or any ohter ways(like using software origin)?In other words,given that $q_e$ and $C_e$ as variables and A,B,g ... |
How to obtain the linear form of Redlich Peterson isotherm model by algebraic tansformation or any ohter ways? |
If you need a quick source of moderate heat, why not use a *single* liquid? [Sodium acetate][1] trihydrate ($\ce{CH3COONa·3H2O}$), for example, releases heat energy on crystallization... and it takes very little to trigger that crystallization! Commercial heat packs contain a "clicker", which makes a sharp vibration. Y... |
Solubility is one of the most complicated phenomena in chemistry. The "why" part of science is extremely difficult to answer in general. As a result one can ask one millions questions as to why iodine is soluble is benzene? What is so unique about benzoic acid? So many organic acids dissolve in benzene including acetic... |
I would suggest that perhaps it wasn't the pillow but another issue altogether.
If in two days your pillow outgassed enough to saturate the wall and the plywood, a couple days should also be sufficient for those to also release any trapped gasses. As I doubt they have any properties better at trapping gases than the ... |
**This is a quote from my textbook**:
>The irregular trend in the first ionisation enthalpy of 3d lmetals,can be accounted for by considering that the removal of one electron alters the relative energies of 4s and 3d orbitals. So the unipositive ions have dn configuration with no 4s electrons.There is thus a reorganiz... |
Thanks for this question, as poor quality memory foam mattresses likely pose a significant health risk in certain locale.
[Per Wikipedia](https://en.wikipedia.org/wiki/Memory_foam) on associated hazards of memory foam, to quote:
>Emissions from memory foam mattresses may directly cause more respiratory irritatio... |
Thanks for this question, as poor quality memory foam mattresses likely pose a significant health risk in certain locale.
[Per Wikipedia](https://en.wikipedia.org/wiki/Memory_foam) on associated hazards of memory foam, to quote:
>Emissions from memory foam mattresses may directly cause more respiratory irritatio... |
Thanks for this question, as poor quality memory foam mattresses likely pose a significant health risk in certain locale.
[Per Wikipedia](https://en.wikipedia.org/wiki/Memory_foam) on associated hazards of memory foam, to quote:
>Emissions from memory foam mattresses may directly cause more respiratory irritatio... |
Thanks for this question, as poor quality memory foam mattresses likely pose a significant health risk in certain locale.
[Per Wikipedia](https://en.wikipedia.org/wiki/Memory_foam) on associated hazards of memory foam, to quote:
>Emissions from memory foam mattresses may directly cause more respiratory irritatio... |
Thanks for this question, as poor quality memory foam mattresses likely pose a significant health risk in certain locale.
[Per Wikipedia](https://en.wikipedia.org/wiki/Memory_foam) on associated hazards of memory foam, to quote:
>Emissions from memory foam mattresses may directly cause more respiratory irritatio... |
How to obtain the linear form of Redlich Peterson isotherm model by algebraic transformation or any other ways? |
I have read (thanks to Stack Exchange) that mixing water and sulfuric acid is exothermic, as is NaOH and HCl.
Are there two 'safe' liquids that can be mixed and produce anywhere near the same amount of heat? By 'safe' I mean they don't come with the same heavy warnings as sulfuric acid or lye. I would like them to b... |
I have just read an article in which they used $\text{WO}_3$ and $\text{WO}_{2.9}$ as precursors, whose objective was to form $\text{WS}_2$, in an atmosphere of Argon by CVD. In one boat there is the powder of S and in another boat there is $\text{WO}_3$ or $\text{WO}_{2.9}$, in an oven with a double temperature zone. ... |
Applying a Legendre transformation on $U = q - w$ we get the familiar $G = H - TS$.
Making an innocent approximation delivers $\Delta G = \Delta H - T\Delta S$.
When one wants to predict the spontainety of a chemical reaction, one gets the $\Delta H$ and the $\Delta S$ for the reaction in question from tables, an... |
Why isn't ΔH = TΔS in ΔG = ΔH - TΔS? |
As your textbook notes, the relative energy of atomic orbitals is not fixed as you start ionizing your atom. As you ionize, all orbitals drop in energy. However, higher angular momentum orbitals drop more than lower ones, and specifically in your case, the $3d$ orbitals drop below the $4s$ orbitals. So consider vanadiu... |
According to my textbook, for Raoult's law we have
$μ_i (vap)=μ_i^* (p_i^*,T)+RT ln(x_i )$
where $μ_i^* (p_i^*,T)$ is the chemical potential at $T$ and $p_i^*$, the preassue of pure $i$. So, when $x_i=1$ we have $μ_i (vap)=μ_i^* (p_i^*,T)$. That's ok, makes sense.
For Henry's law we have
$μ_i (vap)=μ_i^∞ (... |
I have read that nocl dissociates as no+ and cl- and the various reasons stated as such seem fine.But what i dont get is this, if we follow the actual rules of assigning oxidation numbers, we find that nitrogen has got an unit positive charge with an unit positive charge on chlorine too(if we follow the structure of no... |
We know that activation energy is independent of temperature. But during the dehydration of alcohol or any reaction, activation reaction can be increased by following the thermodynamically controlled product, which is favourable at high temperature. So how is it possible? |
Applying a Legendre transformation on $U = q - w$ we get the familiar $G = H - TS$.
Making an innocent approximation delivers $\Delta G = \Delta H - T\,\Delta S$.
When one wants to predict the spontaneity of a chemical reaction, one gets the $\Delta H$ and the $\Delta S$ for the reaction in question from tables, ... |
Activation energy is an experimental result, obtained from the slope of the log of the rate constant vs 1/T. It is usually determined over a rather small domain of temperature, much less than $100°$C. Who knows whether this slope is dependent on T, if it could be measured between, say, $10$ K and $1000$ K ? |
My textbook says that it is not practically feasible to make insoluble salts (say _PbSO<sub>4</sub>_) from other insoluble salts (say _PbO_), without explicitly mentioning the reason for the same.
So, what _is_ the reason? |
Why is it not practical for insoluble salts to be prepared from other insoluble salts? |
I have just read an article in which they used $\ce{WO3}$ and $\ce{WO_{2.9}}$ as precursors, whose objective was to form $\ce{WS2}$, in an atmosphere of argon by CVD. In one boat there is the powder of $\ce{S}$ and in another boat there is $\ce{WO3}$ or $\ce{WO_{2.9}}$, in an oven with a double temperature zone. In the... |
I have read that $\ce{NOCl}$ dissociates to $\ce{NO+}$ and $\ce{Cl-},$ and the various reasons stated as such seem fine.
But what I don't get is this: if we follow the actual rules of assigning oxidation numbers, we find that nitrogen has got an unit positive charge with an unit positive charge on chlorine too (if w... |
My textbook says that it is not practically feasible to make insoluble salts (say _PbSO<sub>4</sub>_) from other insoluble salts (say _PbO_), without explicitly mentioning the reason for the same.
My guess is: if the product is also an insoluble salt, it may deposit on the insoluble reactant, and stop further reacti... |
In my chemistry notes I have two chemical equations as follows
- 2NH3(g)+6Li(s) = 2Li3N(s)+3H2(g)
- 2NH3(g)+2Na(s)=2NaNH2+H2(g)
Before digging into the resons for different products in two equations, when I searched in the internet to find the clear picture of what are the metals(like alkali metals, alkali... |
Do metals react with ammonia gas(not liquid phase)? |
In my chemistry notes I have two chemical equations as follows:
$$
\begin{align}
\ce{2 NH3(g) + 6 Li(s) &-> 2 Li3N(s) + 3 H2(g)}\tag{R1} \\
\ce{2 NH3(g) + 2 Na(s) &-> 2 NaNH2 + H2(g)}\tag{R2}
\end{align}
$$
Before digging into the reasons for different products in two equations, when I searched in the intern... |
Do metals react with ammonia gas (not liquid phase)? |
There are two misconceptions in the OP's question
>We know that activation energy is independent of temperature.
This is not true in general. Granted, over fairly small temperature intervals (for example, going from zero to hundred degrees Celsius is only about 25% change in absolute temperature terms) Arrhenius ... |
A "van't Hoff apparatus" is mentioned as a means of performing a reaction involving gases in a reversible manner, for instance [here][1].
Unfortunately I have been unable to find a description of such a device using a web search (including on this site). It may be that the device has other names. I intuit from the ... |
According to my textbook, for Raoult's law, we have:
$μ_i (vap)=μ_i^* (p_i^*,T)+RT ln(x_i )$
where $μ_i^* (p_i^*,T)$ is the chemical potential at $T$ and $p_i^*$, the pressure of pure $i$. So, when $x_i=1$, we have $μ_i (vap)=μ_i^* (p_i^*,T)$. That's okay and makes sense.
For Henry's law, we have
$μ_i (vap... |
According to my textbook, for Raoult's law, we have:
$$μ_i(\mathrm{vap}) = μ_i^* (p_i^*,T) + RT \ln x_i$$
where $μ_i^* (p_i^*,T)$ is the chemical potential at $T$ and $p_i^*$, the pressure of pure $i$. So, when $x_i=1$, we have $μ_i (vap)=μ_i^* (p_i^*,T)$. That's okay and makes sense.
For Henry's law, we have... |
Activation energy is an experimental result, obtained from the slope of the log of the rate constant vs $1/T$. It is usually determined over a rather small domain of temperature, much less than $100\ \mathrm{^\circ C}$. Who knows whether this slope is dependent on $T$, if it could be measured between, say, $10\ \mathrm... |
I understood the simplified reason for optical activity of a compound based on the difference in the angular velocities of counter-rotating circularly polarized light. The difference is due to the spatial arrangement of different groups with different electronic configurations. Even though it wasn't specified in my tex... |
Do isotopic groups cause optical activity? |
Where does all the energy go which is released when we mix salt with water? |
URGENT Concentration of Vinegar | Titration? |
The hydration energy of NaCl is −774.3 kJ. Then why are we not able to harness that energy and run machines just by mixing salt in water?
Where does all the energy go which is released when we mix salt with water? |
The hydration energy of NaCl is −774.3 kJ. Then why are we not able to harness that energy and run machines just by mixing salt in water? |
> Does the distillation of alcohol cause the fractioning of isotopes[...]?
The short answer is **it depends**.
1. Distillation of ethanol from water can be done nearly to completion. There are [published methods](https://www.ncbi.nlm.nih.gov/pubmed/15287660) for determining isotopic composition of sugars in frui... |
If ammonia is heated to high temperature or subject to photodissociation, a reported radicalization, per this source, [Journal of Chemical Physics: 'Dissociation of NH3 to NH2 + H '](https://aip.scitation.org/doi/10.1063/1.452417):
$\ce{NH3(g) + Heat/UV light/ArF laser -> •NH2 + •H}$
The laser reference is [prov... |
If ammonia is heated to high temperature or subject to photodissociation, a reported radicalization, per this source, [Journal of Chemical Physics: 'Dissociation of NH3 to NH2 + H '](https://aip.scitation.org/doi/10.1063/1.452417):
$\ce{NH3(g) + Heat/UV light/ArF laser -> •NH2 + •H}$
The laser reference is [prov... |
I am currently devising a project to create a kinetic sculpture, similar to [Sachiko Kodama][1]. Does anyone know any suspension liquids that when applied, the ferrofluid floats on top?
[1]: http://sachikokodama.com |
If ammonia is heated to high temperature or subject to photodissociation, a reported radicalization, per this source, [Journal of Chemical Physics: 'Dissociation of NH3 to NH2 + H '](https://aip.scitation.org/doi/10.1063/1.452417):
$\ce{NH3(g) + Heat/UV light/ArF laser -> •NH2 + •H}$
The laser reference is [prov... |
First, a little clarification. The kind of ice you see at ambient pressure, ice I, exists as stacks of bilayers of water molecules. If they are stacked in an ABAB sequence, they form hexagonal ice, and cubic ice in an ABCABC sequence. The difference between the two allotropes is just the stacking of the molecules, so i... |
What solution could I add to a solution of water with dissolved carbon dioxide in order to get the carbon to precipitate out? I believe the ions are H+ and HCO3-
Thanks, Jerid |
Various gasses are currently used to transport and store energy for heating and electricity generation.
Most of them contain carbon:
Methane, propane, butane, carbon monoxide and natural gas.
It could be of advantage to use gasses that do not contain carbon.
One example for that is hydrogen.
Are there ot... |
Are there other carbon free gasses that can be used for energy transport, apart from hydrogen? |
If ammonia is heated to high temperature or subject to photodissociation, a reported radicalization, per this source, [Journal of Chemical Physics: 'Dissociation of NH3 to NH2 + H '](https://aip.scitation.org/doi/10.1063/1.452417):
$\ce{NH3(g) + Heat/UV light/ArF laser -> •NH2 + •H}$
The laser reference is [prov... |
Cyclobutadiene is like benzene in that it has alternating single and double bonds in a ring. However, it's bonds are not the same length, the double bonds being shorter than single bonds. The molecule is rectangular, not square.
How would this be explained?
I have one plausible explanation that I tried to give...that ... |
I just want to make sure I'm understanding buffering capacity correctly.
I've been working on this problem:
>Suppose you have an acetic acid buffer, pKa = $4.74$, at the following pH:
> 1) pH = 4.00
> 2) pH = 4.35
> 3) pH = 4.70
> 4) pH = 5.00
> 5) pH = 5.40
> 6) pH = 5.60
> Which buffer so... |
Am I understanding buffering capacity against strong acid/base correctly? |
I just want to make sure I'm understanding buffering capacity correctly.
I've been working on this problem:
>Suppose you have an acetic acid buffer, $\mathrm{p}K_\mathrm{a} = 4.74$, at the following $\mathrm{pH}$:
> 1) $\mathrm{pH} = 4.00$
> 2) $\mathrm{pH} = 4.35$
> 3) $\mathrm{pH} = 4.70$
> 4) $\mat... |
Cyclobutadiene is like benzene in that it has alternating single and double bonds in a ring. However, it's bonds are not the same length, the double bonds being shorter than single bonds. The molecule is rectangular, not square.
How would this be explained?
I have one plausible explanation that I tried to give...th... |
Why aren't all bonds in cyclobutadiene not equal? |
The purpose of buffers is to keep $\mathrm{pH}$, with the differential buffering capacity $\frac{ \mathrm{d(pH)}}{ \mathrm{d}n}$
If you are interested in the integral buffer capacity across $\mathrm{pH}$ range, than optimal is the buffer with the maximum capacity in the middle of the range.
The rest of the answer dep... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.