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Ethylene has been used in storing potatoes for a while, see this [article][1]. In it, they address the puzzle of a ripening agent acting to prevent sprouting:
> Sprout suppressant properties of apple ‘vapours’ were first reported in 1932 and subsequently, ethylene and apple ‘vapours’ in 193... |
Suppose salt dissolves in water according to the equation NaCl(s) -> Na(aq) + Cl(aq). Since the activity of solid salt is 1, adding salt shouldn't affect sodium and chloride ions at equilibrium. However, if I were to add salt to an unsaturated solution, the salt would dissolve and increase the ion concentrations. Ho... |
If the activity of a solid is one why does adding salt to water increase the salt ion concentration? |
I recently [asked][1] a question about *why the heat of formation of organic radicals and positive ions decreases with their size and degree of branching at the radical or ionic site*. The user "Buttonwood" made the comment that **hyperconjugation** is one of the forms stabilising cations and radicals.
This begs two... |
Ethylene has been used in storing potatoes for a while, see this [article][1]. In it, they address the puzzle of a ripening agent acting to prevent sprouting:
> Sprout suppressant properties of apple ‘vapours’ were first reported in 1932 and subsequently, ethylene and apple ‘vapours’ in 193... |
Recently I've been reviewing concepts belonging to the history of chemistry. But I came stuck at trying to understand a passage which I read from wikipedia entry (and which it seems has been mentioned in different sources). This is related with the law of reciprocal proportions.
It states as this:
> It took 615 p... |
We might have a half cell consisting of the redox couple $Ag^+/Ag$, which for example's sake might be fixed to be at the cathode (i.e. undergoing reduction).
The reaction at the cathode is then
$Ag^+ + e^- \rightarrow Ag$
The standard electrode potential of the $Ag^+/Ag$ couple is $+0.80V$. I've seen the above... |
Why do we write electrode potentials next to chemical reactions? |
We might have a half cell consisting of the redox couple $Ag^+/Ag$, which for example's sake might be fixed to be at the cathode (i.e. undergoing reduction).
The reaction at the cathode is then
$Ag^+ + e^- \rightarrow Ag$
The standard electrode potential of the $Ag^+/Ag$ couple is $+0.80V$ wrt SHE. I've seen t... |
We might have a half cell consisting of the redox couple $Ag^+/Ag$, which for example's sake might be fixed to be at the cathode (i.e. undergoing reduction).
The reaction at the cathode is then
$Ag^+ + e^- \rightarrow Ag$
The standard electrode potential of the $Ag^+/Ag$ couple is $+0.80V$ wrt SHE. I've seen t... |
What did Richter meant to say with the law of reciprocal proportions and how is it related with an acid base reaction? |
What did Richter mean regarding an acid base reaction? |
I was reading up on LA-ICP-MS and MALDI. All the sources I read for LA-ICP-MS simply say that when the laser hits the sample immediately goes into the gas phase. Why doesn't the laser immediately break fragile molecules?
MALDI makes sense to me. You put the sample in a matrix that absorbs UV really well then hit the... |
Potential health issues associated with the immediate exposure to toxic propellant gases have been addressed above by Webber GK.
However, a review of the biochemistry literature does suggest that there can also be long-term consequences from radical-induced illness to the lungs (in particular, [see this source](htt... |
I made a dry cell battery from zinc (Zn), carbon (C) and ammonium chloride (NH4Cl) which produced a current of 0.4 amps and voltage of 1.1V. However when I could not find the redox reaction that was occurring.
What is the chemical reaction happening in the cell? |
We might have a half cell consisting of the redox couple $\ce{Ag+}/\ce{Ag}$, which for example's sake might be fixed to be at the cathode (i.e. undergoing reduction).
The reaction at the cathode is then
$$\ce{Ag+ + e- -> Ag}$$
The standard electrode potential of the $\ce{Ag+}/\ce{Ag}$ couple is $+0.80\ \mathrm... |
Why does the ground state of a Li atom have a total spin of S = 1/2? I get that the total z component of the spin has to be either Ms = 1/2 or Ms = -1/2 because of the Pauli exclusion principle, but that could also correspond to a total spin of S = 3/2, so why is it always S = 1/2? |
I have recently got a custom-made ring from a jeweler. It’s made from a byzantine-period bronze ring enveloped in a gold bangle. The bronze ring is “glued” onto the gold ring through some kind of resin, as far as he told me.
Would bimetalism with rhe corrosion of the bronze ring happen?
Thank you!
 from materials found at home?
I'm aware of computer visualizations (and will make those availabl... |
How can you build a model of tetrahedral coordination from objects found at home? |
Inflate balloons, and tie them «at their stem» like a bouquet of flowers. If you take four of them, not too much inflated, you well demonstrate a situation close to $sp^3$ hybridization. These models equally work well in larger lecture halls by the way, and _intentionally_ using different colors allows many options.
... |
[An interesting study](http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000600009), to quote:
>In terms of caloric content, ethanol is a unique drug whose oxidation by alcohol dehydrogenase (ADH) produces 7.1 kcal per gram of ethanol oxidized. However, it is not known to what extent these calorie... |
An [interesting study](http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000600009), 'Can calories from ethanol contribute to body weight preservation by malnourished rats?', to quote:
>In terms of caloric content, ethanol is a unique drug whose oxidation by alcohol dehydrogenase (ADH) produces 7.... |
I’m wondering what would happen if the filter paper in a vacuum filtration process is bigger than the buchner funnel diameter?
I mean would some differences occurs? Or would the whole experiment damage? If yes, may I know how and why?
|
What happens if the filter paper in vacuum filtration is BIGGER than the buchner funnel diameter? |
Here is a rather simple structure explanation presented on [this site](https://www.masterorganicchemistry.com/2010/07/09/chemical-tetris/). To quote, where 'pieces' refer to an organic molecular with a non-symmetric branching structure:
>You’ll notice something – the simpler the pieces are, the easier they are to st... |
Here is a rather simple structure explanation presented on [this site](https://www.masterorganicchemistry.com/2010/07/09/chemical-tetris/). To quote, where 'pieces' refer to an organic molecular with a non-symmetric branching structure:
>You’ll notice something – the simpler the pieces are, the easier they are to st... |
According to my textbook,
> Lattice enthalpy is the enthalpy change that occurs when one mole of a solid ionic compound is separated into gaseous ions under standard conditions.$^1$
According to the same textbook, this is an endothermic process, which makes sense as a lattice is generally held together by strong ... |
I need to determine as many J values as I can for 3-methoxybenzaldehyde. The peaks overlap a lot, and I don't see the expected ddd or dt pattern that I would expect for the hydrogen on carbon 6. The HSQC I was given has the clearest peaks for the H NMR, so I attached that. Maybe someone with more NMR experience can hel... |
NOTE: Please do not delete this question. It is not a personal health question. **The question has broad utility, in cases where others find themselves in social-distancing or quarantine with need for surface sanitizer, and their only available ingredients are water and powdered oxy-bleach.**
I need a quantity of ... |
I'm taking an undergraduate level class on computer based drug design. The class is more for biology students than people with a strong understanding in physics and computer science.
With that said, I'm having trouble discerning the difference between what molecular docking and scoring functions are.
To me they se... |
Difference between docking and scoring? |
I am completely new to using OpenBabel software.
I have about 9000 pdb files to which, I want to add hydrogens. It will be a very hectic task to open all of them 1 by 1 and then convert each of them. Is there any way I could convert all of them simultaneously.
Also, can you please tell me how to correctly selec... |
Is NH3 a strong ligand or weak? |
If a synthesis reaction is a reaction that two or more substances react together to form just one product. Then how is it that photosynthesis has two products and the end of the which are glucose and oxygen? |
Yes, do use household dilute H2O2 but, in general, do not use commercial percarbonates powders as there contains an additive to convert the friendly percarbonate into more powerful Peracetic acid (PAA). The latter allows the otherwise weak bleaching power of the H2O2 to compete with chlorine-based bleaching. However, t... |
Yes, do use household dilute H2O2 but, in general, do not use commercial percarbonates powders as there contains an additive to convert the friendly percarbonate into more powerful Peracetic acid (PAA). The latter allows the otherwise weak bleaching power of the H2O2 to compete with chlorine-based bleaching. However, t... |
When I was kid and got a huge cut on my finger, I remember my grandmother putting lots of kerosene on my wound, as there was no health facility around.
I want to confirm. Do chemists agree on the antiseptic role of kerosene, or was grandma just using useless remedy? |
Electron transfer rates (k) as derived from Marcus theory assumes i) thermal equilibrium and ii) neglects quantum nature of low-frequency phonon modes. Can anyone explain what is at the heart of these two assumptions? Thanks a lot!
I read this in the context of the electron transfer process in organic semiconductors... |
If a synthesis reaction is a reaction in which two or more substances react together to form just one product, then how is it that photosynthesis has two products; glucose and oxygen? |
I think you're being a little too strict with your definition of what a synthesis reaction is. A better way to describe it might be building more complex molecules from simpler ones.
Wouldn't you say C6H12O6 is more complex than CO2 and H2O? |
Here are two common ways of measuring the entropy change in a reaction:
1. Measure the equilibrium constant $K$ at multiple temperatures. This gives you the Gibbs energy (via $\Delta_r G^\circ = - R T \ln{K}$) and, via the van't Hoff relationship, the enthalpy. You can calculate the entropy from those two.
2. Use... |
Yes, do use household dilute H2O2 but, in general, do not use commercial percarbonates powders as there contains an additive to convert the friendly percarbonate into more powerful Peracetic acid (PAA). The latter allows the otherwise weak bleaching power of the H2O2 to compete with chlorine-based bleaching. However, t... |
In thermodynamics, the heat that transferred to an ideal gas is considered as work that was done on the system? |
My understanding is that a redox couple is an unordered pair of two conjugate species. So we could speak of the redox couple consisting of $Ag$ and $Ag^+$; depending on whether a given redox couple is undergoing oxidation or reduction, we could then write a half equation involving the species given in the redox couple.... |
Does the order of a written redox couple matter? |
In my QM class we are finding the wave functions of the hydrogen atom. In spherical coordinates, these wave functions are functions of 3 variables: $r,$ $\theta,$ and $\phi.$ My professor stated that "*the wave functions of the electron are called orbitals*".
Say, we are interested in the $l = 0$ (or s-orbitals). S... |
I think you're being a little too strict with your definition of what a synthesis reaction is. A better way to describe it might be building more complex molecules from simpler ones.
Wouldn't you say $\ce{C6H12O6}$ is more complex than $\ce{CO2}$ and $\ce{H2O}$? |
>1.
The density at $20^\circ\mathrm{C}$ of a $\pu{0.500 M}$ solution of acetic acid in water is $\pu{1.0042 g/mL}$. What is the molality of the solution? The molar mass of acetic acid is $M(\ce{CH3CO2H})=\pu{60.05 g/mol}$.
>2.
The density at $20^\circ\mathrm{C}$ of a $\pu{0.258 M}$ solution of glucose in water is
... |
In thermodynamics, why is the heat that is transferred to an ideal gas considered as work that was done on the system for an isothermal process? |
I am an oil well integrity engineer. Need help in understanding gas solubility in oil-based drilling mud (OBM) when the mud is gelled. Normally, oil based mud is an emulsion, where continuous phase is some type of oil (~70%), and remaining is dispersed water/brine droplets, various additives to get to desired drillin... |
Normally protein coordinates are generated from electron density, such as that from X-ray scattering experiment. In my case, I want the reverse - PDB to electron density mesh. I thought it was more trivial and a program should be available. But Google did not give me any luck.
Is there any existing python library/pr... |
In my book it is given that first electron gain enthalpy is greater than second for elements. Should we compare the magnitudes in such cases or the actual numbers with signs? Does the same comparision hold with Electron Affinity at 0K? |
For the more recent structures, you can view the density (based on measured diffraction data and the model, so-called 2Fo-Fc density) directly in the protein data bank, e.g. http://www.rcsb.org/3d-view/6QU9?preset=electronDensityMaps:
[![enter image description here][1]][1]
For a theoretical model or a model with... |
The answer is $AuCl_3 + NaCN$
Now I understand that for electroplating, we need gold to be deposited on the copper article, and the electrolyte must enable that deposition. But I don’t know what is the use of $NaCN$ in the process.
Also, if copper is the cathode, then pure gold should be the anode. But the oxida... |
What is the electrolytic bath used in gold-plating of copper articles? |
N2+3H2 ---------> 2NH3, DeltaH = -92.2kj
Now I understand why this reaction isn't carried out in the lowest possible temperature (even though it seems that it should be as it favors the right side of the reaction). As the rate of reaction would be very slow, the amount of NH3 produced would be lesser than the amount... |
I understand why the reaction
$$\ce{N2 + 3 H2 -> 2 NH3} \qquad \Delta H = \pu{-92.2 kJ mol-1}$$
isn't carried out in the lowest possible temperature (even though it seems that it should be as it favors the right side of the reaction). As the rate of reaction would be very slow, the amount of $\ce{NH3}$ produced w... |
> What is so acidic...and basic...?
Nothing.
This derives from the historical perception that silica in geological systems and in melts was in the form of silicic acid ($\ce{H2SiO4}$) and the alkali and alkali earth elements were considered as bases.
We now know that in high temperature silicate liquids (that ... |
Suppose there is a water solution at $25^0C$ with $Na^+$, $Mg^{2+}$ cations and $Cl^-$, $HCO_3^-$ anions. Concentrations of [$Na^+$], [$Mg^{2+}$], [$Cl^-$] and [$HCO_3^-$] are known.
I cannot understand how to apply the **Kohlrausch's law of the independent migration of ions** here: $$ \Lambda_m^0 = \nu_+\lambda_+ + ... |
This is the mass spectrum for 4-methylpentan-1-ol
[![enter image description here][1]][1]
From its structural formula, what could be the fragmentation which results in a peak at m/z = 56?
[1]: https://i.stack.imgur.com/XUDbx.png
I was considering a few possibilities; could it be C3H4O+ ? |
Cause of m/z = 56 peak in 4-methyl-1-pentanol? |
Suppose there is a water solution at $\pu{25 °C}$ with $\ce{Na+},$ $\ce{Mg^2+}$ cations and $\ce{Cl-},$ $\ce{HCO3-}$ anions. Concentrations $[\ce{Na+}],$ $[\ce{Mg^2+}],$ $[\ce{Cl^-}]$ and $[\ce{HCO3-}]$ are known.
I cannot understand how to apply the Kohlrausch's law of the independent migration of ions here:
$$\... |
This is the mass spectrum for 4-methylpentan-1-ol:
[![mass spectrum for 4-methylpentan-1-ol][1]][1]
From its structural formula, what could be the fragmentation which results in a peak at $m/z = 56?$
I was considering a few possibilities; could it be $\ce{C3H4O+}?$
[1]: https://i.stack.imgur.com/XUDbx.p... |
Suppose there is a water solution at $\pu{25 °C}$ with $\ce{Na+},$ $\ce{Mg^2+}$ cations and $\ce{Cl-},$ $\ce{HCO3-}$ anions. Concentrations $[\ce{Na+}],$ $[\ce{Mg^2+}],$ $[\ce{Cl^-}]$ and $[\ce{HCO3-}]$ are known.
I cannot understand how to apply the Kohlrausch's law of the independent migration of ions here:
$$\... |
>A compound $\ce X$ of formula $\ce{C2H5NO2}$ on treatment with $\ce {HNO2}$
$(\ce{NaNO2}+\ce{HCl})$ gives off an inactive gas $\ce Y$ and forms $\ce Z$. When heated with soda lime, $\ce X$ gives $\ce{A(CH5N)}$ soluble in acid. Find the true statements :
>
> 1. $\ce A$ answers carbylamine test.
> 2. $\ce X$ i... |
>A compound $\ce X$ of formula $\ce{C2H5NO2}$ on treatment with $\ce {HNO2}$
$(\ce{NaNO2}+\ce{HCl})$ gives off an inactive gas $\ce Y$ and forms $\ce Z$. When heated with soda lime, $\ce X$ gives $\ce{A(CH5N)}$ soluble in acid. Find the true statements :
>
> 1. $\ce A$ answers carbylamine test.
> 2. $\ce X$ i... |
Why is Electrochemistry often the method of choice for determining Ksp values? |
I need to create a $100\textrm{mL}$ buffer of $\textrm{pH = 9.20}$ with ammonia and ammonium chloride such that $\textrm{pH = }9.20\pm0.50$ with $20\textrm{mL}$ of $0.2\textrm{M } \ce{NaOH}/\ce{HCl}$. I am provided with $0.1\textrm{M}$ ammonia and ammonium chloride.
I used the Henderson-Hasselbalch equation to figur... |
Creating a buffer with with a target pH and given weak base? |
Unfortunately I did not find a high resolution spectrum of this compound, which would have quickly answered your question.
Nevertheless, ionized alcohols and even more primary alcohols have a main fragmentation pathway which is the loss of water to yield an ionized alkene. In this case, the corresponding alkene woul... |
Between an electrode and an electrolyte there exists an interfacial potential difference.
Many authors give the electrode potential to be the electric potential of the electrode relative to the electrolyte. I have a few problems with this, and was wondering whether anyone could help.
We define the electrode pote... |
Between an electrode and an electrolyte there exists an interfacial potential difference.
Many authors give the electrode potential to be the electric potential of the electrode relative to the electrolyte. I have a few problems with this, and was wondering whether anyone could help.
We define the electrode pote... |
Between an electrode and an electrolyte there exists an interfacial potential difference.
Many authors give the electrode potential to be the electric potential of the electrode relative to the electrolyte. I have a few problems with this, and was wondering whether anyone could help.
We define the electrode pote... |
It appears that perhaps **water** may have symmetric hydrogen bonds between oxygen atoms, but it would take at least 60 GPa of pressure to make water to bond like that.
Article named very descriptively "[Compression of Ice to 210 gigapascals: Infrared Evidence for a Symmetric Hydrogen-Bonded Phase][1]" proves it:
... |
> Why isn't then the reaction carried out at the highest possible temperature since the rate of reaction would be very high and the yield would be very high consequently as well?
The rate constant would be high, but that does not mean that the net forward rate is high. If you start without product, the initial rate ... |
[![Problem Statement][1]][1]
[1]: https://i.stack.imgur.com/xqicB.png
An isotopic variant of the molecule SF6 is S19F418F2, with the two 18F nuclei oriented axially, so that the 18F-S-18F angle is 180°and the four 19F nuclei form a square in a plane perpendicular to the 18F-S-18F axis.All of the bond lengths ... |
[![Problem Statement][1]][1]
[1]: https://i.stack.imgur.com/xqicB.png
An isotopic variant of the molecule SF6 is S19F418F2, with the two 18F nuclei oriented axially, so that the 18F-S-18F angle is 180°and the four 19F nuclei form a square in a plane perpendicular to the 18F-S-18F axis.All of the bond lengths ... |
Normally protein coordinates are generated from electron density, such as that from X-ray scattering experiment. In my case, I want the reverse - PDB to electron density mesh. I thought it was more trivial and a program should be available. But Google did not give me any luck.
Is there any existing python library/pr... |
[![Problem Statement][1]][1]
[1]: https://i.stack.imgur.com/xqicB.png
An isotopic variant of the molecule SF$_6$ is S$^{19}$F$_4^{18}$F$_2$, with the two $^{18}$F nuclei oriented axially, so that the $^{18}$F-S-$^{18}$F angle is 180°and the four $^{19}$F nuclei form a square in a plane perpendicular to the $^... |
[![Problem Statement][1]][1]
[1]: https://i.stack.imgur.com/xqicB.png
An isotopic variant of the molecule SF$_6$ is S$^{19}$F$_4^{18}$F$_2$, with the two $^{18}$F nuclei oriented axially, so that the $^{18}$F-S-$^{18}$F angle is 180°and the four $^{19}$F nuclei form a square in a plane perpendicular to the $^... |
Yes, do use household dilute H2O2 but, in general, do not use commercial percarbonates powders as they can contain an additive to convert the friendly percarbonate into more powerful Peracetic acid (PAA). The latter allows the otherwise weak bleaching power of the H2O2 to compete with chlorine-based bleaching. However,... |
I need to create a $100\textrm{mL}$ buffer of $\textrm{pH = 9.20}$ with ammonia and ammonium chloride such that $\textrm{pH = }9.20\pm0.50$ with $20\textrm{mL}$ of $0.2\textrm{M } \ce{NaOH}/\ce{HCl}$. I am provided with $0.1\textrm{M}$ ammonia and ammonium chloride salt.
I used the Henderson-Hasselbalch equation to ... |
I’m currently investigating a method to chemically pretreat cellulosic waste as bisorbents for enhanced uptake of lead in water. I intend to measure the initial and final concentration of water to record the change in concentration of aqueous lead via a chelatometric titration.
In my experiment, I’ll be performing fi... |
Sorry to tell you a bad news. Classical methods, like titrimetry or gravimetry do not work very well at low concentrations. Failure would be a strong word. The beauty of EDTA is that it forms 1:1 complex with most metals. Pb is not an exception. If your lead solution is 0.000001 M, your EDTA solution should be 0.000001... |
What happens to the intramolecular bonds when a network covalent substance is melted? I understand that in covalent molecular substances, the intermolecular bonds weaken between the molecules once molten. My confusion is with what happens to the bonds between network covalent substances when melted.
- Do the intra... |
With the Coronavirus in full swing around the globe, I wanted an answer to this, particularly since my dad has just been diagnosed with Leukaemia.
We can't find hand wash anywhere but instead I just bought some Radox shower gel and put that in a hand soap bottle.
Is there a significant difference between hand soa... |
Is there a difference between hand soap and body soap with killing viruses? |
It's given in text that "Electrode potential among other things depends upon: enthalpy of sublimation,ionization enthalpy and hydration enthalpy." I could understand why it would depend upon ionization enthalpy as less is the IE easily we could remove the electron thereby reducing the other reactant. But I couldn't fig... |
Why does electrode potential depend upon enthalpy of hydration and sublimation? |
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