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As to the question does gaseous NH3 directly react with metals, other than complex formations, a more accurate short answer is likely no. A better answer is a reaction may proceed from heat (or other energy sources, like light) induced breakdown products of ammonia interacting with the metal.
A review of the literat... |
I have been reading papers on machine learning and deep learning methods that have been trying to generate molecules. https://doi.org/10.1021/acscentsci.7b00572 I have seen a shift of interest from SMILES representations to Graph molecular representations in the past couple years. I was wondering what are possible bene... |
I have been reading papers on machine learning and deep learning methods for learning molecular space and generating molecules. These methods use different representations of the molecules. The most popular ones in the field include SMILES and graphs [e.g. [this][1] and [this][2]]. I have seen a shift of interest from ... |
As to the question does gaseous NH3 directly react with metals, other than complex formations, a more accurate short answer is likely no. A better answer is a reaction may proceed from heat (or other energy sources, like light) induced breakdown products of ammonia interacting with the metal.
A review of the literat... |
In saponification reaction ethyl ethanoate is made to react with NaOH to form sodium acetate as the soap and ethanol as a by-product.
My question is : Why don't we use ethanoic acid instead of ethyl ethanoate to form sodium acetate which is the soap and water as another product? |
Why ethyl ethanoate and not acetic acid? |
> $\ce{A ->[(i)EtMgCl][(ii)H2O] Et3C-OH}$
>A can be:
>a) $\ce{COCl2}$
>b) $\ce{EtCOOEt}$
>c) $\ce{Et2CO}$
>d) $\ce{All}$
The answer should be (d) but is marked as (a) in the answer key.
Option (c) obviously gives the required product, as does (b). I derived this scheme for (a)
$$\ce{2COCl2 + 2Et... |
I already referred to [this][1] similar question but it yielded no explanation for the reason. Cations and anions of similar sizes stabilize each other through lattice energy effects in the solid state. This explains the stability of the alkali metal carbonates and sulphates as one moves down the group. Applying a simi... |
Organophosphorus compounds are known to inhibit the enzyme acetylcholinesterase (AChE). This occurs when the OPC phosphorylates the serine-203 residue of the enzyme. If the enzyme is not reactivated in time, a second reaction occurs, whereby one of the alkyl groups on the OP molecule is hydrolyzed off, giving the alcoh... |
I was wondering whether the compression factor of a real gas (given by Z = Vreal/Videal) is supposed to be measured while keeping pressure constant?
I was attempting to answer the question below and got stumped at part iii.) because I had trouble finding out which was the dominating force being that when I tried cal... |
So I was searching about the difference between redox reactions and Lewis Acid-Base reactions and came across classical example of latter,
$$\ce{NH3 + BH3 \rightarrow NH3BH3}$$
Now in this example what is the oxidation state of borane? Is it $+4$, if yes then can this example be considered a type of redox reaction... |
In most cases, STO integrals are evaluated assuming that the orbitals are directed towards each other, using spherical harmonics; however, in GTO-based software Cartesian GTOs are used, with the orbitals being aligned along the x, y or z axis.
Is there any way to evaluate STO integrals using Cartesian STOs, or conv... |
How do STO-based computer programs implement the STO integral formulae? |
I was wondering whether the compressibility factor of a real gas (given by $Z = V_{real}/V_{ideal}$) is supposed to be measured while keeping pressure constant?
I was attempting to answer the question below and got stumped at part (iii) because I had trouble finding out which was the dominating force being that when... |
I was wondering whether the compressibility factor of a real gas (given by $Z = V_{\mathrm{real}}/V_{\mathrm{ideal}}$) is supposed to be measured while keeping pressure constant?
I was attempting to answer the question below and got stumped at part (iii) because I had trouble finding out which was the dominating for... |
I have been reading papers on machine learning and deep learning methods for learning molecular space and generating molecules. These methods use different representations of the molecules. The most popular ones in the field include SMILES and graphs [e.g. [this][1] and [this][2]]. I have seen a shift of interest from ... |
All these choices are arbitrary. Nobody can do justice by summarizing 200 years of atomic weights (now atomic masses) history. Atomic reference scales have changed, earlier hydrogen was taken as 1 (exact) and sometimes oxygen was taken as 16 (exact). Other numbers have been chosen as well. When a mass spectrometer was ... |
I have been reading papers on machine learning and deep learning methods for learning molecular space and generating molecules. These methods use different representations of the molecules. The most popular ones in the field include SMILES and graphs [e.g. [this][1] and [this][2]]. I have seen a shift of interest from ... |
> $\ce{A ->[(i)EtMgCl][(ii)H2O] Et3C-OH}$
>A can be:
>a) $\ce{COCl2}$
>b) $\ce{EtCOOEt}$
>c) $\ce{Et2CO}$
>d) $\ce{All}$
The answer should be (d) according to me, but is marked as (a) in the answer key.
Option (c) obviously gives the required product, as does (b). I derived this scheme for (a)-
... |
I know that diazotization of amines proceeds via the generation of the nucleophile NO+ and thereafter, the NH2 group acts as a nucleophile and shares it's charge density with NO+. After a series of rearrangements the diazonium salts are obtained. However, if one had to compare the ease/ rate of diazotization, what shou... |
I have been reading papers on machine learning and deep learning methods for learning molecular space and generating molecules. These methods use different representations of the molecules. The most popular ones in the field include SMILES and graphs [e.g. [this][1] and [this][2]]. I have seen a shift of interest from ... |
I was reading [this paper][1] on molecular graph generators using deep learning algorithms.
> $\dots$ to ensure the generation of syntactically and semantically valid
> graphs.
The output molecular graph should at least satisfy the following constraints:
1. Valency: Number of incident edges to an atom shal... |
I was reading [this paper][1] on molecular graph generators using deep learning algorithms.
> $\dots$ to ensure the generation of syntactically and semantically valid
> graphs.
The output molecular graph should at least satisfy the following constraints:
1. Valency: Number of incident edges to an atom shal... |
I know that diazotization of amines proceeds via the generation of the nucleophile $\ce{NO+}$ and thereafter, the $\ce{NH2}$ group acts as a nucleophile and shares it's charge density with $\ce{NO+}$. After a series of rearrangements the diazonium salts are obtained. However, if one had to compare the ease/ rate of dia... |
>Suppose I have a beaker containing $\ce{CuSO4}$ solution and I dip $\ce{Cu}$ rod in it. Now my question is what reactions are going to take place?
On a microscopic level, copper ions can approach the rod and pick up two electrons. Or copper atoms can detach from the rod, leaving two electrons behind. On a macroscop... |
Suppose I have a beaker containing $\ce{CuSO4}$ solution and I dip $\ce{Cu}$ rod in it. What reactions are going to take place? Is the $\ce{Cu}$ rod going to acquire any positive charge?
I am asking this question to clear my doubt regarding a Daniell cell as to why $\ce{Cu}$ rod used in the cell should be positive... |
I know that diazotization of amines proceeds via the generation of the nucleophile $\ce{NO+}$ and thereafter, the $\ce{NH2}$ group acts as a nucleophile and shares it's charge density with $\ce{NO+}$. After a series of rearrangements the diazonium salts are obtained. However, if one had to compare the ease/ rate of dia... |
Regardless of whether a substance is in a vacuum, it will vaporize if some fraction of its particles have enough energy (due to their temperature) to exceed their binding energy. [Binding energy][1] is the energy contained in the intermolecular bonds holding a substance together. It is definitely possible for the par... |
Attached is a phase diagram for carbon dioxide. At $p = 0$, it appears that the substance will exist as a gas regardless of temperature.
My questions are:
1. For **any** liquid at a fixed temperature, is it possible to vaporize it completely by simply reducing its pressure isothermally?
2. For **any** solid... |
Does everything exist as a gas at p = 0? |
The following question arises from a question I found in my book.
The problem states the following:
> Experimentally it has been determined that the value of the first
> energy of ionization of oxygen is lesser than the first energy of
> ionization of nitrogen. Select the statement which explains this:
The a... |
Why does the first energy of ionization of oxygen is lesser than the first energy of ionization of nitrogen? |
The following question arises from a set of statements from which I'm asked to state whether they are true or false.
This is as follows:
> Indicate which of the following statements are true or false
1. On $\underset{np}{\underline{\uparrow}\,\underline{\uparrow}\,\underline{\downarrow}}$ there is a transgress... |
Does it exist a transgression to Hund's rule of maximum multiplicity principle in this given electron box notation? |
The following question arises from a set of statements from which I'm asked to state whether they are true or false.
This is as follows:
> Indicate which of the following statements are true or false
1. On $\underset{np}{\underline{\uparrow}\,\underline{\uparrow}\,\underline{\downarrow}}$ there is a transgress... |
It appears that a clean preparation of stannous (or stannic nitrate), other than by the possible direct action of gaseous NO2 on SnO (or SnO2?), as suggested generally [by Wikipedia](https://en.wikipedia.org/wiki/Nitrogen_dioxide) below, is not readily found. To quote:
>Conversion to nitrates
>NO2 is used to gene... |
While reading [this paper][1] on molecular graph generators using deep learning algorithms, I encountered the terms *syntactically* and *semantically* valid molecular graphs:
> $\dots$ to ensure the generation of syntactically and semantically valid
> graphs.
The output molecular graph should at least satisfy th... |
While reading [this paper][1] on molecular graph generators using deep learning algorithms, I encountered the terms *syntactically* and *semantically* valid molecular graphs:
> $\dots$ to ensure the generation of syntactically and semantically valid
> graphs.
The output molecular graph should at least satisfy th... |
From Wikipedia:
> Helmholtz free energy is a thermodynamic potential that measures the
> useful work obtainable from a closed thermodynamic system at a
> constant temperature and volume (isothermal, isochoric)
I struggle to understand the Helmholtz more than the Gibbs because of the isocholoric nature of its d... |
How does one extract the work characterized by the Helmholtz energy? |
As explained in the other answers, water ice may not actually become cubic at low temperature. In fact, if formed at higher temperature as the usual hexagonal phase, water ice will remain so when cooled. There is no thermodynamic driving force to rearrange the hexagonal structure to a cubic one.
We can expand on t... |
From Wikipedia:
> Helmholtz free energy is a thermodynamic potential that measures the
> useful work obtainable from a closed thermodynamic system at a
> constant temperature and volume (isothermal, isochoric)
I struggle to understand the Helmholtz more than the Gibbs because of the isochoric nature of its def... |
I know that diazotization of amines proceeds via the generation of the electrophile $\ce{NO+}$ and thereafter, the $\ce{NH2}$ group acts as a nucleophile and shares it's charge density with $\ce{NO+}$. After a series of rearrangements the diazonium salts are obtained. However, if one had to compare the ease/ rate of di... |
If sulfuric acid barely evaporates, why we can smell it? Or does it give off sulfur dioxide gas? |
If sulphuric acid barely evaporates, why we can smell it? |
There's a general principle that applies anytime you calculate a change in a property:
The change in the value of a property in going from an initial state to a final state is always:
value(final state) - value(initial state)
For instance, what is the change in elevation (which we'll call height... |
I came across this graph, which clearly shows a large difference between the boiling points of alkanes and their equivalent alcohols.
However, it is clear that as chain length increases, the difference in boiling point between alkanes and alcohols decreases.
What is the main reason for this?
I have read that... |
The question arises from trying to get where does the values of $-2$, $0$, $+2$, $+4$ and $+6$ from the electron configuration.
The electron configuration for sulphur $(Z=16)$ is $[Ne]3s^23p^4$.
It makes sense that to complete the octet sulphur needs to gain two electrons hence it will have $-2$, but it can lose ... |
How electron configuration is related to the oxidation state of an element such as sulphur and can this be extended for elements in other blocks? |
Lets say CO2 and C2H6 are both in gas form(not vapour). Now which one will be easier to liquify? My take is that the molecule of C2H6 should be much larger than CO2 hence greater van der walls force. And also the critical temperature of C2H6 is higher than that of CO2. So it should be relatively easy to make C2H6 vapou... |
Which Gas is easier to liquify Ethane or Carbon-di-oxide? |
Let's say CO2 and C2H6 are both in gas form, not vapour. Now which one will be easier to liquify? My take is that the molecule of C2H6 should be much larger than CO2 and hence have greater Van der Waals forces. And also the critical temperature of C2H6 is higher than that of CO2, so it should be relatively easy to make... |
Let's say $\ce{CO2}$ and $\ce{C2H6}$ are both in gas form, not vapour. Now which one will be easier to liquify? My take is that the molecule of $\ce{C2H6}$ should be much larger than $\ce{CO2}$ and hence have greater van der Waals forces. And also the critical temperature of $\ce{C2H6}$ is higher than that of $\ce{CO2}... |
Is ethane or carbondioxide easier to liquify? |
I need to find the Lewis structure of the ion $\ce{SCH^-}$.
I think the Lewis structure should be:
$\ce{S=C-H}$, with one lone pair on the carbon and two lone pairs surrounding the sulfur.
Is this correct?
|
What is the correct lewis structure of SCH⁻? |
As explained in the other answers, water ice may not actually become cubic at low temperature. In fact, if formed at higher temperature as the usual hexagonal phase, water ice will remain so when cooled. There is no thermodynamic driving force to rearrange the hexagonal structure to a cubic one.
We can expand on t... |
My teacher isn't very good at helping me solve this problem. I keep getting the answer, but I don't know why I am getting it. Could you please help me understand this problem and why you should do this specific step?
> A $\pu{1.00 g}$ sample of $\ce{Na2CO3.10H2O}$ was dissolved in $\pu{20.0 mL}$ of distilled water. ... |
I wish to calculate the energy for a protein where the position of all the C-alpha atoms is known.
One way is to calculate the pairwise distances between the atoms and then look up a probability distribution to determine the likelihood that the distance for that particular pair is the given value, take the negative... |
I want to remove water hardness using Ion exchange resin filter. Does anyone tried this method I want to know if this method really lowers the hardness. What is the best method of regenerating resin filter? How much water it uses for regenerating process? |
I came across the phrase "Silicone Rubber/Paraffin@Silicon Dioxide" also written as $\ce{SR/pa@SiO2}$, utilising the `@` symbol.
How can I understand what this means? |
What is the @ symbol used for in material science? |
The following question arises from a question I found in my book.
> Experimentally it has been determined that the value of the first
> energy of ionization of oxygen is lesser than the first energy of
> ionization of nitrogen. Select the statement which explains this:
>
1. The higher electronegativity of oxygen... |
Why is the first energy of ionization of oxygen lesser than that of nitrogen? |
Is ethane or carbon dioxide easier to liquify? |
>The minimum pressure for the existence of liquid solution is?
>1. $0.6\;\mathrm{atm}$
2. $0.8\;\mathrm{atm}$
3. $0.77\;\mathrm{atm}$
4. $0.9\;\mathrm{atm}$
Although this seems to be an informative question, I want to know the process by which we get this answer.
I know that the critical pressure for ... |
From the given data, the molar volume is $$v=\frac{150\ cc}{3\ moles}=50\ cc/mole=0.05\ L/mole$$
In terms of specific volume, the van der Waals equation reads:
$$\left(P+\frac{a}{v^2}\right)(v-b)=RT$$
So, solving for the pressure gives:
$$P=\frac{a}{v^2}+\frac{RT}{v-b}$$
So, to get the pressure you don't n... |
From the given data, the molar volume $V_\mathrm m$ is $$V_\mathrm m=\frac{150\ \mathrm{cm^3}}{3\ \mathrm{mol}}=50\ \mathrm{cm^3/mol}=0.05\ \mathrm{L/mol}$$
In terms of molar volume, the van der Waals equation reads:
$$\left(p+\frac{a}{V_\mathrm m^2}\right)(V_\mathrm m-b)=RT$$
So, solving for the pressure gives:... |
According to Elliot, Hatahway & Slade (1966) cited by [this paper][1], Co(II) with nitrite ligands is low spin.
[![enter image description here][2]][2]
So maybe it is just a typo. For d7 low spin, you would expect one unpaired electron.
[1]: http://scripts.iucr.org/cgi-bin/paper?S0567740880005535
[2]: htt... |
So, DMSO (dimethyl sulfoxide) can form metal complexes in both $\mathrm{\kappa O}$ and $\mathrm{\kappa S}$ mode i.e. binding with the oxygen or the sulfur respectively. The general explanation given is that softer metal ions bind to the soft centre S and hard metal ions bind to the hard centre O.
From the IR data it... |
Why does the binding of DMSO to metal via the S atom (k-S) strengthens the S=O bond? |
For electrochemical cells we know
$$
\Delta G = \Delta G^{\ominus} + RT\ln Q=- RT\ln Keq + RT\ln Q=-nFE
$$
So for lithium ion batteries the reactions are
Cathode
$$ CoO2 + Li+ + e- <=> LiCoO2 $$
Anode
$$ LiC6 <=> C6 + Li+ + e^-$$
Overall
$$ LiC6 + CoO2 <=> C6 + LiCoO2 $$
Is it safe to say the cobalt oxide... |
I agree that there seems to be a shift towards using graph representations over SMILES strings. I personally think this is a good thing, and I'll try to explain why, but even if there's nothing inherently better about graph representations of molecules, there is a very practical reason people are moving towards graph r... |
OKay I learned in class that equivalence point is the time of neutralization, where the # of moles of acids and base present is in equivalence/same amount.
Now I was also told that Half equivalence point is when [HA] = [A$^-$] , the concentration of a weak acid = concentration of conjugate base.
Problem:
I'm g... |
What is the difference between Half Equivalence point and Equivalence point? |
Like it says on the tin. Several sites say that the pH of rainfall is somewhere between 5 and 5.5, and a few seem to suggest that it averages around 5.7. But why is the pH of rain much lower than that if pure water, which is 7? |
Why is the pH of rainfall much lower than pure water? |
A question asks:
> This question refers to isolated gaseous atoms. In which atom are all electrons paired? Ba, Br, S or Si?
I thought it was Ba as its electron configuration is [Xe] 6s2.
However, the answer says Si, which seems incorrect to me.
Could someone please confirm the answer for me?
Thanks |
For electrochemical cells we know
$$
\Delta G = \Delta G^{\ominus} + RT\ln Q=- RT\ln Keq + RT\ln Q=-nFE
$$
So for lithium ion batteries the reactions are
Cathode
$$ \ce{CoO2 + Li+ + e- <=> LiCoO2} $$
Anode
$$ \ce{LiC6 <=> C6 + Li+ + e^-}$$
Overall
$$\ce{ LiC6 + CoO2 <=> C6 + LiCoO2} $$
Is it safe to say t... |
Why is absorbance in UV-VIS spectrometer negative even after calibration? |
Possible causes include:
- If it is a dispersive instrument (simultaneous recording of blank and sample in two cells): is the logic about which one is sample and blank set correctly? At least some spectrometers by PerkinElmer and Shimadzu allow to swap how front and rear path are managed by the software.
- How ... |
Ref :
https://www.electropages.com/blog/2020/01/why-lithium-sulphur-batteries-are-taking-so-long-be-used-commercially
> Because they continually shuttle between the electrodes, they never change back into a neutral state (which the surface polysulphide ions do)
I don't think this explains the 'shuttle effect... |
What exactly is the 'shuttle effect' in sulfur batteries? |
I want to ask a question about the sum of two variables and the error associated with the process.
I was learning about calculating errors in the physical labs at school and was taught that the following formula was used to calculate errors:
> $\frac{\triangle Z}{Z} = \frac{\triangle A}{A} + \frac{\triangle B}{B... |
I want to ask a question about the multiplication of two variables and the error associated with the process.
I was learning about calculating errors in the physical labs at school and was taught that the following formula was used to calculate errors:
> $\frac{\triangle Z}{Z} = \frac{\triangle A}{A} + \frac{\tr... |
I am wondering if the direction of electron flow in a voltaic cell be reversed such that the cathode becomes the anode and vice versa. I understand this is not possible for two standard half-cells, but what about non-standard half-cells at STP ? |
Can the direction of electron flow in a voltaic cell be reversed? |
So, DMSO (dimethyl sulfoxide) can form metal complexes in both $\mathrm{\kappa O}$ and $\mathrm{\kappa S}$ mode i.e. binding with the oxygen or the sulfur respectively. The general explanation given is that softer metal ions bind to the soft centre S and hard metal ions bind to the hard centre O.
From the IR data it... |
>Now I was also told that Half equivalence point is when [HA] = [A−] , the concentration of a weak acid = concentration of conjugate base.
That is correct. You make the weak acid *in situ* when you titrate a weak base with a strong acid, or when you titrate a weak acid with a strong base. At the half equivalence poi... |
I'm imagining a strong base like NaNH2 attacking the adjacent carbon of the ether, giving the oxygen a lone pair and forming an alkoxide. NH3 has a pKa of 36 while an alcohols (conjugate acid of alkoxides) have a pKa of around 15 so shouldn't this be favorable? |
Why can't strong bases cleave ethers? |
I agree that there seems to be a shift towards using graph representations over SMILES strings. I personally think this is a good thing, and I'll try to explain why, but even if there's nothing inherently better about graph representations of molecules, there is a very practical reason people are moving towards graph r... |
**EDIT**: *Can going to non-standard conditions reverse the cell potential of a voltaic cell?* I have already answered that question, in the affirmative, for a simple tin and lead galvanic cell: https://chemistry.stackexchange.com/a/116734/79678.
What follows is an elaboration with some specific values and illustrat... |
**EDIT**: *Can going to non-standard conditions reverse the cell potential of a voltaic cell?* I have already answered that question, in the affirmative, for a simple tin and lead galvanic cell: https://chemistry.stackexchange.com/a/116734/79678.
What follows is an elaboration with some specific values and illustrat... |
>![enter image description here][1]
I tried finding the slope between two points but I keep getting wrong values, how does one find the initial rate by using such graphs?
So I started by trying to find a slope of two points, $(0,0.4)$ and $(10,0.2)$ after calculations I got $-0.02$, which is the opposite of the ... |
>Can going to non-standard conditions reverse the cell potential of a voltaic cell?
I have already answered that question, in the affirmative, for a simple tin and lead galvanic cell, here: https://chemistry.stackexchange.com/a/116734/79678.
What follows is an elaboration with some specific values and illustrativ... |
I am looking to try an experiment incorporating potassium lactate into soap making. This seems to be new territory for soap makers in that sodium lactate is usually used. I found a bottle of "Lactic Acid 88%" at a beer making supplier and already have 90% potassium hydroxide but do not know how much of one is needed to... |
This is a standard exam question pertaining to the kinetics material that is typically presented in a first year general chemistry course. Usually the coverage is restricted to discussion of zero, first and second order kinetics. From the photo of the exam question, the decay is **apparently** first order, i.e., $$\mat... |
This is a standard exam question pertaining to the kinetics material that is typically presented in a first year general chemistry course. Usually the coverage is restricted to discussion of zero, first and second order kinetics. From the photo of the exam question, the decay is **apparently** first order, i.e., $$\mat... |
Consider some general parallel first order process, where A $\rightarrow$ B and A $\rightarrow$ C (rate constants *k<sub>1</sub>* and *k<sub>2</sub>* respectively)
The overall rate equation of this process is said to be $-\frac{d[A]}{dt} = k_1[A] + k_2[A]$
I get the impression that this is derived from the additi... |
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