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How do we represent a molecule in text form?
A molecule, as a computer scientist I see it as a connected graph of atoms. A connected graph means that beginning at any atom, there is a path to any other atom in the graph.
The interesting question is, how do we represent these as text?
Specific questions are:
... |
How do we represent a molecule in text form? |
How do we represent a molecule in text form?
A molecule, as a computer scientist I see it as a connected graph of atoms. A connected graph means that beginning at any atom, there is a path to any other atom in the graph.
The interesting question is, how do we represent these as text?
Specific questions are:
... |
Correct me If I am wrong and also I am not sure that this answers your full question or not as it only provides an answer to your specific questions.
[Here][2] are some rules for writing chemical formulas. Kindly read them first.
> 1) Is $\ce{H2O}$ different than $\ce{OH2}$? That is, does order matter, or what ... |
Correct me If I am wrong and also I am not sure that this answers your full question or not as it only provides an answer to your specific questions.
[Here][2] are some rules for writing chemical formulas. Kindly read them first.
> 1) Is $\ce{H2O}$ different than $\ce{OH2}$? That is, does order matter, or what ... |
Correct me If I am wrong and also I am not sure that this answers your full question or not as it only provides an answer to your specific questions.
[Here][2] are some rules for writing chemical formulas. Kindly read them first.
> 1) Is $\ce{H2O}$ different than $\ce{OH2}$? That is, does order matter, or what ... |
I'm working on my own 3D molecule viewer for my AP Chem class. So far everything's going together nicely. There's a couple of things I'm not sure about though...
Is there a certain rule of thumb or standard for what colors each element inside a molecule should be? For example, Oxygen is red and hydrogen is white in... |
How should Elements be Colored? And how many bonds? |
I'm working on my own 3D molecule viewer for my AP Chem class. So far everything's going together nicely. There's a couple of things I'm not sure about though...
Is there a certain rule of thumb or standard for what colors each element inside a molecule should be? For example, Oxygen is red and hydrogen is white in... |
How should elements be colored? And how many bonds does an atom have? |
We've just spilled the can of used meat-grease we collect so that it doesn't go down the drain and it turns out it was rotten. Very stenchily rotten. Now the granite counter-top and the wood-lamenant floor of the kitchen smell very bad even after repeated cleanings with (1) dish-soap, (2) vinegar and (3) Murphy's Oil S... |
It has been stated that the molar conductance of strong electrolytes is not affected to a greater extent on dilution and so to find the limiting value of molar concentration we can extrapolate the graph. But as the concentration would near zero shouldn't the molar condutance decrease sharply to the range of say 10^-8 w... |
Why does NF4- have a larger bond length than NF3? Usually in molecules the bond angle increases to reduce repulsion but, here the bond length increases. Why is it so? Do in other molecules also the bond length increase along with bond angle in this type of situations? |
Why does $NF_4^-$ have a larger bond length than $NF_3?$ Usually in molecules the bond angle increases to reduce repulsion but, here the bond length increases. Why is it so? Does the bond length increase with the bond angle in other cases of such kinds of molecules? |
Why does $\ce{NF4^-}$ have a larger bond length than $\ce{NF3}?$ Usually in molecules the bond angle increases to reduce repulsion but, here the bond length increases. Why is it so? Does the bond length increase with the bond angle in other cases of such kinds of molecules? |
It has been stated that the molar conductance($\Lambda_m$) of strong electrolytes is not affected to a greater extent on dilution and so to find the limiting value of molar concentration($\Lambda_m^0$) we can extrapolate the graph of molar conductance vs the concentration ($\sqrt c$). But as the concentration would nea... |
If you are right, and the smell is coming from an amine, then you may need to clean a lot more than you have. Even if you think you've done a thorough cleaning, amines have very low odor thresholds. I can't find specific numbers for putrescine and cadaverine; however another amine generated in decaying animal protein... |
As per topic, I was wondering why the Tm of the polymers PGA, PLA and PLGA are in the following order. Does it correlate to their ability to undergo hydrolysis?
PGA>PLA>PLGA |
Is there a correlation between the susceptibility of a polymer to undergo hydrolysis and it's melting point? |
Suppose I have a white paper originally. Then it is placed in a trunk, where soda spills occasionally and gasoline gas/gasoline also spills due to no gas tank cover. Over time, this paper becomes discoloured.
How do I make it white again? What equipment do I use? |
How do I make a paper white again? |
Consider the following acidic reaction:
$\ce{As -> H2AsO4- + AsH3}$
How would I go about balancing this using the half reaction/ion-electron method? |
If I prepare the silver nitrate solution or any other solution, how can I know the shelf life of this solution? I know that it depends on the stability of the substance, but maybe there is some document which give information and is interesning how realy it was found. |
I guess that a long time ago there was a lot of $\ce{H2S}$ in the atmosphere and then the $\ce{H2S}$ could have reacted with that lead oxide to form $\ce{PbS}$?
On wikipedia it says (under Lead(II)oxide,reactions) :
>The red and yellow forms of this material are related by a small change in enthalpy:
>PbO(... |
Here are some **standard electrode potentials**:-
$$SO_4^{2-} + 4H^+ +2e^-\rightarrow SO_2 +2H_2O\\E^o=0.17V\\
NO_3^-+4H^++3e^-\rightarrow NO+2H_2O\\E^o=0.97V\\
NO_3^-+2H^++e^-\rightarrow NO_2+H_2O\\E^o=0.78V$$
When nitric acid reacts with a metal, either $NO_2$ or $NO$ is formed? How do you **predict which ... |
Why does $\ce{BF4^-}$ have a larger bond length than $\ce{BF3}?$ Usually in molecules the bond angle increases to reduce repulsion but, here the bond length increases. Why is it so? Does the bond length increase with the bond angle in other cases of such kinds of molecules? |
Would Chlorine or Chloramine gas show up on a VOC test? My apartment was cleaned using chlorox and lysol, and there has been a smell that's been lingering for about 10 days. The air was tested with a VOC meter but nothing came up. Would Chlorine and Chloramine have shown up on this test? |
Would Chlorine or Chloramine gas show up on a VOC test? |
![enter image description here][1]I have been looking for a physical explanation for entropy and enthalpy variations. An example would be the air system of a vehicle, where people say we have a strong enthalpy and entropy variations along the exhaust line, which is not the case in the fresh air line. How could that be ... |
For the coloring part I would suggest you look at the [CPK][1] coloring convention.
As for the decision whether a bond is a single or a double bond: You could make this decision based on the bond length between two atoms. But you will need to find typical values for single, double and triple bonds for every combinat... |
For the coloring part I would suggest you look at the [CPK][1] coloring convention.
As for the decision whether a bond is a single or a double bond: You could make this decision based on the bond length between two atoms. But you will need to find typical values for single, double and triple bonds for every combinat... |
Given the carbanion, $ R_3C^- $, the carbon is $ sp^3 $ hybridized unless it is participating in resonance. This is clear from its steric number.
In drawing its orbital diagram, however, I am having trouble. I know that if this was a neutral carbon atom, it would look like this:
<ul>
<li>3s: _</li>
<li>2p: ↑ ↑ ... |
We had analytical chemistry experiments to determine acidic radicals from a mixture of two salts. After the chloroform-chlorine water test for distinction between halides($\ce salt solution + H_2SO_4 +CHCl_3 + Cl_2 water$) when I emptied the test-tube in the sink, all of it suddenly turned yellow.
What reaction coul... |
While working at CNC engraving, I had at my disposal a small bottle of liquid used to stain brass for creating signs etc - engrave a writing, stain the engraving, then grind/polish the flat topmost layer to remove the colored layer and leave it only in engraved depressions.
The bottle didn't reveal much about compos... |
What substance is used for staining brass? |
I was having a conversation when the topic of sublimation came up. Prior to the discussion, I had always thought that sublimation was caused by a great pressure/temperature difference, but another person stated that whether or not an element sublimates depends on its composition.
Will any element sublimate under the... |
Is sublimation caused by an environmental difference or an element's composition? |
I know that a molecule is more stable when a free radical is on a secondary carbon over a primary carbon, but how about when there is a lone pair of elections that can be placed on a secondary or primary? Is there any difference in the stability of the molecule or does that only apply to free radicals? |
My instructor has been drawing 3D molecules that show the directionality of non-bonding electron pairs and p-orbitals. I've been trying to find references online that show this process, but I'm having a hard time finding anything useful.
Can someone please explain the process or link to a source that does? I've incl... |
My instructor has been drawing 3D molecules that show the directionality of non-bonding electron pairs and p-orbitals. I've been trying to find references online that show this process, but I'm having a hard time finding anything useful.
Can someone please explain the process or link to a source that does? I've incl... |
$$\ce{2Na(l) +2NH3 (g) ->2NaNH2(s) + H2}$$
$$\ce{CH3Cl (alc) +NH3 (alc) -> Ch3NH2 (alc) +HCl}$$
Doesn't ammonia donate a proton in both cases? |
Why does ammonia act as an acid in only the first of these two reactions? |
$$\ce{2Na(l) +2NH3 (g) ->2NaNH2(s) + H2}$$
$$\ce{CH3Cl (alc) +NH3 (alc) -> CH3NH2 (alc) +HCl}$$
Doesn't ammonia donate a proton in both cases? |
$$\ce{2Na(l) +2NH3 (g) ->2NaNH2(s) + H2(g)}$$
$$\ce{CH3Cl (alc) +NH3 (alc) -> CH3NH2 (alc) +HCl(alc)}$$
Doesn't ammonia donate a proton in both cases? |
While neucleons (protons and neutrons) are responsible for the mass of the atom, electrons are responsible for its size. The neucleons are in the tiny nucleus of the atom. The electrons take up a vast area around this necleus. If you keep on increasing the subatomic particles (electrons, protons, etc), defintely the at... |
I was wondering if someone could help me find references available that will help me solve the following problems. These are *not* homework problems, but are suggested problems that were given to me by my instructor.
![enter image description here][1]
[1]: https://i.stack.imgur.com/fD2nb.jpg
I'm specifical... |
Concerning your first question: I found that the book ["Organic Chemistry" by Clayden, Warren, Wothers and Greeves][1] and here especially the 8th chapter contains a very good and readable introduction to acidity and basicity. As for your second question: If you want to know why reactions occur in the way they do you'... |
Concerning your first question: I found that the book ["Organic Chemistry" by Clayden, Warren, Wothers and Greeves][1] and here especially the 8th chapter contains a very good and readable introduction to acidity and basicity. After you have worked through this chapter you should be able to explain why certain molecul... |
I see that Gaussian has feature to set periodic boundary conditions sspecifuing the parameter PBC in the input file. Does it do it via the plane wave basis set? Also, the question is whether it is efficient to use Gaussian to compute the relaxed lattice constant, band structure and DOS for solids or it is better to use... |
I have some questions on the nomenclature-<br>
(1) In $H_2O$ we have $H$ written first and $O$ is second but when it comes to Hydroxyl group $OH$ the $O$ comes first, Why?
<br>
(2)Why is Propanal called Propion-aldehyde and not Propane- aldehyde? |
I see that Gaussian has feature to set periodic boundary conditions specifying the parameter Tv in the input file. Does it do it via the plane wave basis set? Also, the question is whether it is efficient to use Gaussian to compute the relaxed lattice constant, band structure and DOS for solids or it is better to use p... |
The Thermodynamic efficiency of any cell (especially Fuel cells) is given as $$\frac{\Delta G}{\Delta H} \times 100$$
I understood that since $\Delta G$ is the useful work obtained in the ideal case, the efficiency equation must have it in the numerator but I fail to see the intuition (or maths) behind the $\Delta H... |
Thermodynamic cell efficiency? |
Thermodynamic cell efficiency clarifications? |
Concerning your first question: I found that the book ["Organic Chemistry" by Clayden, Warren, Wothers and Greeves][1] and here especially the 8th chapter contains a very good and readable introduction to acidity and basicity. After you have worked through this chapter you should be able to explain why certain molecul... |
You won't find a general formula for the shelf life of a solution. A silver nitrate solution will have a very short shelf life if it is kept in the sunlight, whereas potassium nitrate could last for years. The shelf life is also going to be very strongly dependent on the quality of the container. [Think about what h... |
What is the proper procedure for working with KHMDS? I would like to use it to deprotonate a compound and have a bottle of KHMDS in toluene. Does it need to be handled under inert atmosphere? And is it soluble in halogenated solvents? |
If the wavefunction of the electron in a box of length L is $$\psi{(x)}=\sqrt{\frac{2}{L}}\cdot\sin{\frac{n\pi x}{L}}$$
. What would be the probability of finding the electron between $0.5L$ and $0.75L$?.
From postulate 1 of quantum mechanics I know that $\large 1=\int_{0}^{L}{\psi(x) \psi^{*}(x)dx}$
Trying out ... |
If the wavefunction of the electron in a box of length L is $$\psi{(x)}=\sqrt{\frac{2}{L}}\cdot\sin{\frac{n\pi x}{L}}$$
What would be the probability of finding the electron between $0.25L$ and $0.75L$?.
From postulate 1 of quantum mechanics I know that $\large 1=\int_{0}^{L}{\psi(x) \psi^{*}(x)dx}$
Trying out a... |
What complicated the synthesis of Upsalit ( anhydrous MgCO3), for it to be synthesized and published in 2013 as opposed to the 20th century, as one would expect for such a simple salt? |
Why was anhydrous magnesium carbonate "Upsalit" discovered so late? |
What complicated the synthesis of Upsalite (anhydrous MgCO3), for it to be synthesized and published in 2013 as opposed to the 20th century, as one would expect for such a simple salt? |
I have came across the following statement : "the oxidation state $+II$ is stable for the elements of the alkalin earth metals" , the same is true for the elements of the first group , i've looked for a possible explanation and heard that it has a relation with the charge densities of the elements , if that's true what... |
I use Sodium persulfate to etch a copper board to manufacture home made Printed Circuit Board (PCB), and I use the same etching tank on the below photo which has no cover on the top. I wonder if it is okay to keep it like that at the room temperature or would it evaporate?
![enter image description here][1]
... |
Why was anhydrous magnesium carbonate “upsalite” discovered so late? |
What complicated the synthesis of upsalite (anhydrous MgCO3), for it to be synthesized and published in 2013 as opposed to the 20th century, as one would expect for such a simple salt? |
In [The Big Bang Theory Season 3 Episode 1 "The Electric Can Opener Fluctuation"][1]
Leonard gives Penny a [snowflake][2] that never melt. He said something chemical gas name when he try to explain but I don't understand what he said exactly so I can do some research about that. You can watch it on this [youtoube vi... |
Is it possible to save insoluble snowflake? |
I am learning quantum chemistry and I am trying to understand the statement in a .pdf I'm reading which states
"The energy transition associated with the spectral transitions observed is:
$$\Delta E = E_{LUMO} - E_{HOMO} = \frac{(N+1)h^2}{8mL^2}$$
where $L$ is the length of the "box" (it's talking about particle in ... |
Can someone please explain the intuition around the answers to this problem:
![enter image description here][1]
[1]: https://i.stack.imgur.com/j9xjJ.jpg
I'm finding it very confusing because it seems like you have to nitpick between two resonance structures to get the desired results. Do we just always loo... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/koSM2.png
Why do we deprotonate that specific hydrogen as opposed to any other one? What information does the table on the right give us (it seems unrelated to citric acid- where does the flourine come from)? |
How will citric acid react with pyridine (question about deprotonation in citric acid)? |
The table on the right looks like a standard group of acids shown to illustrate the effect of inductive withdrawing on carboxylic acid pKa. The first two structures are relevant to the question. The table may have been copied from somewhere else because it had both structures on it. Two of the pKa values in the table a... |
In [The Big Bang Theory Season 3 Episode 1 "The Electric Can Opener Fluctuation"][1]
Leonard gives Penny a [snowflake][2] that will never melt. He said some type of chemical gas name when he try to explain, but I don't understand what he said exactly so I can't do any research about that. You can watch it on this [Y... |
Is it possible to save an insoluble snowflake? |
> Do we just always look for the "lowest" possible VSEPR in any resonance structure?
Yes. Consider the two resonance contributors below for a N,N-dimethylacetamide, which has a functional group in common with your molecule. The rule of thumb I teach is: **if an atom appears to be $sp^2$-hybridized in one resonance ... |
The Thermodynamic efficiency of any cell (especially Fuel cells) is given as $$\frac{\Delta G}{\Delta H} \times 100$$
I understood that since $\Delta G$ is the useful work obtained in the ideal case, the efficiency equation must have it in the numerator but I fail to see the intuition (or maths) behind the $\Delta H... |
I have came across the following statement : "the oxidation state $+II$ is stable for the elements of the alkalin earth metals" , the same is true for the elements of the first group , i've looked for a possible explanation and heard that it has a relation with the charge densities of the elements , if that's true what... |
Can someone explain chelation and its relation to monodentate and tridentate ligands? I dont understand what they mean by chelate effect and chelating rings. |
In organic chemistry we can classify carbon atoms as primary, secondary, tertiary, or quaternary based on the number of additional carbon atoms bonded to the carbon atom of interest. The definitions in the textbook I teach from ([Klein, 1st Ed. Wiley, 2011][1]), as well as in several others I have, and from from [sever... |
Is the nomenclature "primary", "secondary", "tertiary", and "quaternary" carbon atoms limited to $sp^3$ carbon atoms? |
Can it be isolated at room temperature? Or even at any temperature? |
Why is Aluminium Carbonate unstable? |
How can I get ChemSketch to get N and H atoms closer while still operating in ACS style and without adjusting atom sizes? |
The Thermodynamic efficiency of any cell (especially Fuel cells) is given as $$\frac{\Delta G}{\Delta H} \times 100$$
I understood that since $\Delta G$ is the useful work obtained in the ideal case, the efficiency equation must have it in the numerator but I fail to see the intuition (or maths) behind the $\Delta H... |
$H_2 \ \ C=C=O$ what is the group of the molecule? how to characterize it and how this is dissimilar to ketone ? If we add o2 with it then will we get $CO_2?$ |
$\ce{H_2 \ \ C=C=O}$ what is the group of the molecule? how to characterize it and how this is dissimilar to ketone ? If we add $\ce{O2}$ with it then will we get $\ce{CO2}$? |
As, your question isn't much clear and it needs to be focused little more.
From current state of this question, I can provide you the answers for specific questions that **I get to understand from its current state.**
>$\ce{H_2 \ \ C=C=O}$
>What is the group of the molecule?
Well this is known as [ketene][... |
Every now and then you reach into the bathroom cabinet to find that some pill or ointment you where planning to use has gone past its expiration date.
I am interested whether this expiration date has any value. In a short search I found [this article from Harvard medical school][1] stating that some test found that ... |
Why do pharmaceutical drugs have a expiration date? |
It's a good question, and I cannot answer your specific example but can give some generic reasons why pharmaceuticals have an expiration date:
- **Degradation** of the compound/formulation over time. This obviously comes to mind, but there is more to it than meets the eye. For example, you gave the example of an oin... |
According to IUPAC rules, names of chemical elements should not be capitalized. See [Wikipedia’s take](http://en.wikipedia.org/wiki/Chemical_element#Element_names) on the issue:
> According to IUPAC, chemical elements are not proper nouns in English; consequently, the full name of an element is not routinely capital... |
Why do people often capitalize element names? |
I'm not able to understand how the following are aromatic.
My first doubt is whether I have to include the lone pair of electrons while applying the Huckel Rule to these compounds?
If yes, then in what situations should I take into account the lone pair of electrons?
![enter image description here][1]
... |
How are the following aromatic? |
I'm not able to understand how the following are aromatic.
My first doubt is whether I have to include the lone pair of electrons while applying the Huckel Rule to these compounds?
If yes, then in what situations should I take into account the lone pair of electrons?
![enter image description here][1]
... |
In extraction of $\ce{Sn}$ from $\ce{SnO2}$, why this reaction **gives $\ce{CO}$ instead of $\ce{CO2}$** in carbon reduction method?
$\ce{SnO2 + C -> Sn + CO}$ |
My 7th grader is embarking on a long-term science project and I'm on tap to "help." He is showing a strong interest into finding ways to get drinking water to the masses. His idea is that we need to find inexpensive and efficient desalination processes. So, we are exploring current desalination processes to see what ma... |
I have no problem with identifying whether a given molecule has geometrical isomerism if it's not cyclic. But cyclic compounds are confusing for me. For eg: How to check whether the following molecule posses geometrical isomerism?
![enter image description here][1]
[1]: https://i.stack.imgur.com/CYn0d.png |
Is there any specific methods to check for geometrical isomersim in cyclic compounds? |
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