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I don't know if why we add Al for the reaction between Nitrate and a base so it would release NH3 gas.
So what I want to know is if what is the **role of Al here**?
And why do we have to add it in excess?
Can we do this with every nitrate? ( in my case I came across the reaction of Sodium Nitrate and Sodium hydr... |
Why do we need to add Al in excess for the reaction between a nitrate and a base to give ammonia? |
It is well known that, even in periods 3 and higher, the bonding in so-called "hypervalent" main-group molecules nearly always do not involve d-orbitals, and I've heard that it's because the d-orbitals are just too high in energy.
I now have a question: if the energetic difference is the only problem, then can bonds i... |
Is there any actually observed excited state of a "hypervalent" main-group molecule that actually involves d-orbitals? |
Hydroxide and nitrate alone do not react with each other.
Their reaction with aluminium is the part of the classical quantitative determination of nitrate content by destilation of produced ammonia and by the back acid titration.
Nitrite + ammonium ions interfere, but the former can be eliminated due their high re... |
Hydroxide and nitrate alone do not react with each other.
Their reaction with aluminium is the part of the classical quantitative determination of nitrate content by distillation of produced ammonia and by the back acid titration.
Nitrite + ammonium ions interfere, but the former can be eliminated due their hi... |
In an experiment, I have two endothermic reactions taking place simultaneously
$$\begin{aligned} \ce{A + B -> C + D}\\ \ce{E + G -> Z + F}\end{aligned}$$
$\ce{C}$ and $\ce{Z}$ also take place in a reaction to form the final product of the process $\ce{J}$. In my experiment, I have to use a single heating source, ... |
In an experiment, I have two endothermic reactions taking place simultaneously:
$$
\begin{align}
\ce{A + B &-> C + D}\tag{1}\\
\ce{E + G &-> Z + F}\tag{2}
\end{align}
$$
$\ce{C}$ and $\ce{Z}$ also take place in a reaction to form the final product of the process $\ce{J}$. In my experiment, I have to use a si... |
My textbook states that,
"Resonance stabilizes the molecule as the energy of the resonance hybrid is less than the energy of any single canonical structure"
by giving two examples: $O_{3}$ and $CO_{2}$.
while I can see that clearly in case of $O_{3}$ molecule, I can't see that how resonance lead to lowering of energy... |
I searched in the internet but most of them said that there are 38 transition metals. But our text book says that group 12 or the group of zinc CAN'T BE COUNTED as transition metals. Which already puts the number to 37? Moreover Scandium, La and Ac also can't be counted as transition metals. That puts the number to 34.... |
My textbook states that
> Resonance stabilizes the molecule as the energy of the resonance hybrid is less than the energy of any single canonical structure
by giving two examples: $\ce{O3}$ and $\ce{CO2}.$
While I can see that clearly in case of $\ce{O3}$ molecule, I can't see that how resonance lead to loweri... |
My textbook (NCERT *Chemistry. Part I. Textbook for Class XI* \[1, p. 106\]) states that
> Resonance stabilizes the molecule as the energy of the resonance hybrid is less than the energy of any single canonical structure
by giving two examples: $\ce{O3}$ and $\ce{CO2}.$
While I can see that clearly in case of ... |
It is well known that, even in periods 3 and higher, the bonding in so-called "hypervalent" main-group molecules nearly always do not involve d-orbitals, and I've heard that it's because the d-orbitals are just too high in energy.
I now have a question: if the energetic difference is the only problem, then can bonds i... |
I was presented today with the following molecule:
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/lOOnP.png
and asked the splitting pattern of $\ce{H_a}$ given that up to $\ce{^3J}$ and $\ce{^4J}$ coupling is allowed.
I thought that $\ce{H_a}$ couples to $\ce{H_b}$, $\ce{H_c}$ a... |
In many books there are said that Alchohols are hydrocarbons, and some says they are not. On the other hand Phenols are said aeromatic hydrocarbons. It is well known that Phenols are not Alchohol. Which is correct and why? |
Can vinylic lone pairs resonate?
For example, in methyl isocyanate, $\ce{CH3CNO}$, shown below,
[![enter image description here][2]][2]
it seems that the nitrogen lone pair can resonate with the carbon oxygen double bond, generating a resonance structure something like acetonitrile oxide:
[![enter image desc... |
Can vinylic lone pairs resonate? |
In many books there are said that Alchohols are hydrocarbons, and some says they are not. On the other hand Phenols are said aromatic hydrocarbons. It is well known that Phenols are not Alchohol. Which is correct and why? |
Are Phenol and Alchohol both hydrocarbons? |
Shakespeare apparently said "What’s in a name? That which we call a rose, by any other word would smell as sweet." Rule number no. 1, don't trust the internet until and unless you have some idea about the credentials of the website (and this comes with experience).
The usage of the term *transition metal* is nothing... |
I was presented today with the following molecule:
[![2-(cyclopenta-2,4-dien-1-ylidene)-1-methylpyrrolidine][1]][1]
and asked the splitting pattern of $\ce{H_a}$ given that up to $\mathrm{^3J}$ and $\mathrm{^4J}$ coupling is allowed.
I thought that $\ce{H_a}$ couples to $\ce{H_b}$, $\ce{H_c}$ and $\ce{H_d}$ g... |
Shakespeare apparently said "What’s in a name? That which we call a rose, by any other word would smell as sweet." Rule no. 1, don't trust the internet until and unless you have some idea about the credentials of the website (and this comes with experience).
The usage of the term *transition metal* is nothing but hi... |
Which name is the Preferred IUPAC Name? 3-methyl-4-oxobutanenitrile or 3-formylbutanenitrile?
I feel the second one is the PIN, since it's shorter than the first one. But, I haven't been able to navigate the IUPAC Blue Book, regarding such cases. |
3-methyl-4-oxobutanenitrile or 3-formylbutanenitrile? |
To study if this reaction is spontaneous I proceed in this way:
$$\ce{2H_{3}O^{+} +Fe ->H_{2} +Fe^{2+} + 2H_{2}O}$$
First I write the two semireaction:
$$reduction: \ \ \ce{2H_{3}O^{+} +2e^{-} -> H_{2}} $$
$$oxydation: \ \ \ce{Fe -> 2e^{-} +Fe^{+}} $$
Then I write the scheme of the cell:
$$\ce{Fe|Fe^{2+}||H_{3}O^... |
Why $$\ce{2H_{3}O^{+} +Fe ->H_{2} +Fe^{2+} + 2H_{2}O}$$ is spontaneous in standard conditions? |
Which name is the Preferred IUPAC Name of the above molecule? 3-methyl-4-oxobutanenitrile or 3-formylbutanenitrile?
I feel the second one is the PIN, since it's shorter than the first one. But, I haven't been able to navigate the IUPAC Blue Boo... |
In methyl isocyanate, $\ce{CH3CNO}$, shown below,
[![enter image description here][2]][2]
it seems that the nitrogen lone pair can resonate with the carbon oxygen double bond, generating a resonance structure something like acetonitrile oxide:
[![enter image description here][1]][1]
In that case, why is th... |
Can this sp2 lone pair resonate? |
To study if this reaction is spontaneous I proceed in this way:
$$\ce{2H_{3}O^{+} +Fe ->H_{2} +Fe^{2+} + 2H_{2}O}$$
First I write the two semireaction:
$$reduction: \ \ \ce{2H_{3}O^{+} +2e^{-} -> H_{2}} $$
$$oxidation: \ \ \ce{Fe -> 2e^{-} +Fe^{+}} $$
Then I write the scheme of the cell:
$$\ce{Fe|Fe^{2+}||H_{3}O^... |
Why is the reaction spontaneous in standard conditions? |
Why is this reaction spontaneous in standard conditions? |
Title says the question, pretty much.
For example, in the Newman projection of ethane, the carbon hydrogen bond angles are $120$ degrees, not $109.5$ degrees, as they actually are in an $\text{sp}^3$ hybridized center. Why is this so, and does it have any effect on the arguments traditionally derived from Newman pro... |
Why are Newman Projections drawn with 120 degrees when actually sp3 carbons are 109.5 degrees? |
In methyl isocyanate, $\ce{CH3CNO}$, shown below,
[![enter image description here][2]][2]
it seems that the nitrogen lone pair can resonate with the carbon oxygen double bond, generating a resonance structure something like acetonitrile oxide:
[![enter image description here][1]][1]
In that case, why is th... |
The answer given is an epoxide.
But is an epoxide stable at room temperature?
And also epoxides tend to open in presence of water. Even if Methyl alcohol is treated as a solvent, then too methyl alcohol is more acidic than water..then if in wat... |
[![Reaction of 2‐bromo‐1‐phenylethan‐1‐one with sodium borohydride in methanol][1]][1]
The answer given is an epoxide.
But is an epoxide stable at room temperature?
And also epoxides tend to open in presence of water. Even if methyl alcohol is treated as a solvent, then too methyl alcohol is more acidic than wat... |
I have seen various discussions about the triple point of Gallium determined to a very precise value, so precise that it is used as a reference for NIST scales and measurements.
However, these reference related documents mean 'temperature' only when talking about triple point. Triple-point is defined as a (temperatu... |
Without quantum mechanics, it becomes a bit sloppy, but the general principle is easy to grasp:
The nucleus is positive, and surrounded by a number of negative electrons matching the charge of the nucleus.
Once the electrons get pulled too close to the core, they start repelling each other strongly, so there is s... |
> I get that oxygen is the terminal electron acceptor in oxidative phosphorylation. But why is it essential to accept these electrons and remove them as H2O?
A redox reaction is made of two half reactions. Neither one of them is more or less important; the combination of both determines the energetics of the reactio... |
I'm trying to determine how to calculate proper measurements for a 5% concentration of a vitamin C ester powder (ascorbyl palmitate) mixed in a 50/50 carrier oil mixture (jojoba oil/squalane oil) with 2% vitamin E oil (α-Tocopherol).
The powder is measured in `mg` and the oils in `mL`.
Densities:
- Jojoba oil... |
I want to ask a question about the symmetry of an FO for $\ce{[CuL2]^-}$ where L is a $1e^-$ donor sigma bonding ligand (e.g. Me).
For the ligand orbitals, I produced the following orbitals shown below:
[![Ligand Orbitals of CuL2][1]][1]
and also used the character table to assist me in assigning symmetry. ... |
I’m teaching myself electrochemistry, and this question is from the general introduction of the book I’m using. According to Bard’s Electrochemical Methods book, in a given cell, the background limits ‘are the potentials where the cathodic and anodic currents start to flow at a working electrode _when it is immersed in... |
> If the molecules in a sample of ice at $-15^\text{o} \text{C}$ and $1$ bar all have their kinetic energy doubled, then what is the final phase?
The answer is gas, but I am not sure how to get this answer.
I was wondering if the equation $k=\frac{3}{2}*R*T$ still holds in this case, even though the molecules a... |
Is kinetic energy proportional to temperature for non-gases? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/c1JiA.png
From what I've learnt, I understand that the bond enthalpy is defined as the energy required to break one mole of a specific bond.
In the question above, I opted for answer C as it was the only one with the products in the for... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/nTAzB.png
From what I understand, electrophiles are electron deficient and therefore would be attracted to the electron-rich benzene ring. So would the correct answer be A? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/5gfOX.png
For a polymer to form from a monomer, the monomer requires open bonds to attach itself to another monomer. Logically for me, it requires a double bond so I would go for answer C. But can the benzene ring actually open up to under... |
What is the radius of the hydride ($\ce{H-}$) ion? There are several sources with conflicting reports on the same.
[Inorganic Chemistry: Principles of structure and Reactivity][1] cites Pauling’s 1960 study of the hydride ion, stating that
> it has a radius of 208 pm compared to 216 pm for the iodide ion
This w... |
How does the Enthalpy of vapourization change when impurities are added? I know that the boiling point of a substance increases on addition of impurities, but how does the Enthalpy of vapourization change? Is less heat needed to convert the liquid from a solution to a gas?
*Related:* [This question][1] deals with a... |
Is there any aqueous solution (or simple method) to remove trace level of sulfur dioxide/nitrogen monoxide and nitrogen dioxide in a gas stream? |
> If the molecules in a sample of ice at $\pu{-15 °C}$ and $\pu{1 bar}$ all have their kinetic energy doubled, then what is the final phase?
The answer is gas, but I am not sure how to get this answer.
I was wondering if the equation $\displaystyle k = \frac{3}{2}RT$ still holds in this case, even though the mole... |
What is the radius of the hydride $(\ce{H-})$ ion? There are several sources with conflicting reports on the same.
[Inorganic Chemistry: Principles of structure and Reactivity][1] cites Pauling’s 1960 study of the hydride ion, stating that
> it has a radius of 208 pm compared to 216 pm for the iodide ion
This w... |
In kryptomerism assignment, there was a question to compare more stable tautomeric form between 4-pyridone (**1**) and 4-pyridinol (**2**):
[![1: 4-pyridone; 2: 4-pyridinol][1]][1]
**Answer**: 4-pyridone.
My friend gave two plausible reasons:
1. $\ce{C=O}$ is more stable than $\ce{C=N}.$
2. $\ce{-N=}$ wi... |
I am conducting research for a new drug that contains powdered sodium bicarbonate, and the drug will need to be sterilized after placement into it's container/closure system. Typically, this is performed with steam, at 122.5 °C for 15 minutes, but in the case of sodium bicarbonate, this would cause decomposition:
$$... |
I live in Bangkok and read on [how water comes to customers here][1]:
I understand from the chart that water go through Thon Buri treatment plant (west Bangkok) and Mahasawat treatment plant (east Bangkok) before they are pumped and transferred into customers.
In the chart I clicked the links for these two treatm... |
Does treated water in big cities heated (boiled)? |
$75$% of $2$ moles of A is $1.5$ mole. $1,5$ mol A produce twice as much of B or C. This makes $3$ mol of B and/or C. It remains $2$ - $1.5 = 0.5$ mol A. The total number of moles is $3 + 0.5 = 3.5$ mol. Where is the difficulty ? |
> Which equation represents the $\ce{N-H}$ bond enthalpy in $\ce{NH3}?$
> $$
\begin{align}
&\textbf{A.} &\ce{NH3(g) &-> N(g) + 3 H(g)}\\
&\textbf{B.} &\ce{1/3 NH3(g) &-> 1/3 N2(g) + H(g)}\\
&\textbf{C.} &\ce{NH3(g) &-> 1/2 N2(g) + 3/2 H(g)}\\
&\textbf{D.} &\ce{NH3(g) &-> .NH2(g) + .H(g)}
\end{align}
$$
Fro... |
How do you find the bond enthalpy from an equation? |
In kryptomerism assignment, there was a question to compare more stable tautomeric form between 4-pyridone (**1**) and 4-pyridinol (**2**):
[![1: 4-pyridone; 2: 4-pyridinol][1]][1]
**Answer**: 4-pyridone.
My friend gave two plausible reasons:
1. $\ce{C=O}$ is more stable than $\ce{C=N}.$
2. $\ce{-N=}$ wi... |
I was presented today with the following structure and asked to comment on the splitting of the proton $\ce{H_a}$.
[![Molecule of concern][1]][1]
I was asked
> What is the chemical shift (below) and splitting pattern for $\ce{H_a}$ up to and
including $\ce{^4J}$?
I relabelled the molecule as shown:
... |
I live in Bangkok and read [how water comes to customers here][1]:
I understand from the chart that water go through Thon Buri treatment plant (west Bangkok) and Mahasawat treatment plant (east Bangkok) before being pumped and transferred to the customer.
In the chart I clicked the links for these two treatment p... |
Does water in big cities get heated (boiled) for treatment? |
Can $CH_3-CHCl-CH_3$ and $CH_3COCl$ give the iodoform test?
I thought $CH_3COCl$ having the keto-methyl group would show the iodoform test while $CH_3-CHCl-CH_3$ will not since it's not a secondary alcohol but an alkyl halide.
|
Can $CH_3-CHCl-CH_3$ and $CH_3COCl$ give the idoform test? |
Can $\ce{CH3-CHCl-CH3}$ and $\ce{CH3COCl}$ give the iodoform test?
I thought $\ce{CH3COCl}$ having the keto-methyl group would show the iodoform test, while $\ce{CH3-CHCl-CH3}$ will not since it's not a secondary alcohol but an alkyl halide.
|
Can 2‐chloropropane and acetyl chloride give the idoform test? |
Can 2‐chloropropane and acetyl chloride give the iodoform test? |
Does the salt bridge in galvanic cells resemble the ATP pump in the inner mitochondrial membrane? And if yes than did someone use this pH difference in harvesting this energy?
Note: I have searched about such method of harvesting energy but I didn't find. |
Does the salt bridge in galvanic cells resemble the ATP pump in the inner mitochondrial membrane? And if yes than did someone use this pH difference in harvesting this energy? |
The number of optical isomers possible for the given organic molecule is?
$\ce{CH_3-C^*H(OH)-CHCl-CH_2Cl}$ (the configuration is fixed at $\ce{C^*}$)
The given answer is 2.
The carbon marked with an asterisk is chiral, and the carbon to the right of it is also chiral. Doesn't that give 4 isomers? What does "config... |
In an experiment, I have two endothermic reactions taking place simultaneously:
$$
\begin{align}
\ce{A + B &-> C + D}\tag{1}\\
\ce{E + G &-> Z + F}\tag{2}
\end{align}
$$
$\ce{C}$ and $\ce{Z}$ also take place in a reaction to form the final product of the process $\ce{J}$. In my experiment, I have to use a si... |
I was presented with the following compound and asked to comment on the splitting of the proton $\ce{H_a}$ in $\ce{^1H}$ NMR.
[![Molecule of concern][1]][1]
The question presented today was:
> What is the chemical shift (below) and splitting pattern for $\ce{H_a}$ up to and
including $\ce{^4J}$?
I rela... |
Rate is calculated as change in concentration over change in time, so usually M/s ($mol\ L^{-1}$). Say I'm calculating it for ammonium hydroxide, and I have a 20% solution of it, so my final rate is in %/s. Is this proper format, or should I calculate for $mol\ L^{-1}$? |
Can I express the rate of a reaction as percent per second (%/s)? |
I would like to understand how to create a molecular orbital diagram for the hydroxide ion from scratch. This includes understanding the shape of the molecular orbital.
Here is an attempt I have come up with:
[![enter image description here][1]][1]
Where the top MO is sigma* and the bottom is simply sigma.
But th... |
Molecular orbital diagram of hydroxide ion? |
Rate is calculated as change in concentration over change in time, so usually $\pu{M/s}$ $(\pu{mol L-1 s-1}).$
Say, I'm calculating it for $20\%$ solution of ammonium hydroxide, so my final rate is in $\pu{\%/s}.$ Is this a proper format, or should I calculate for $\pu{mol L-1}?$ |
I was given the diagram of $\ce{BF3}$'s LUMO and asked to assess its bonding character as shown below:
[![Unannotated BF3 HOMO LUMO][1]][1]
Below is the model answer for the annotated version.
I managed to correctly answer the HOMO MO with the same annotations but was confused here slightly.
The LUMO In... |
consider a sample of ca(No3)2.10H2o ... to remove water i need to heat it to 100c but will this high temperature do damage to the calcium salt (maybe burn it)? |
will roasting a sample of ca(No3)2.10H2o to 100c burn the calcium salt and remove water ? or will the calcium salt be as it is |
Both chloride and bromide ions are present in 10-fold excess over silver ions. That means that the chloride and bromide concentration in solution will not drop by much (they will remain major species).
The solubility product of AgCl is 200-times higher than that of AgBr. If both AgCl and AgBr precipitate, the chlori... |
Consider a sample of $\ce{Ca(NO3)2.10H2O}$. To remove water, I need to heat it to $\pu{100 ^\circ C}$ but will this high temperature decompose it or will I get the anhydrous salt? |
Does calcium nitrate dekahydrate dehydrate or decompose upon heating to 100 degrees celsius? |
What does it mean by " concentrations are (value) in relation to each other"? |
According to the Colby Chemistry Database, the bond angle of $\ce{PBr3}$ and $\ce{PCl3}$ are around $101$ degrees, but the bond angle of $\ce{PH3}$ is $92$ degrees. (Source: [PCl3][1] [PBr3][2] [PH3][3])
There was a previous question on Stack Exchange about the bond angle difference in $\ce{PF3}$ and $\ce{PH3}$ here... |
Why do PBr3 and PCl3 have larger bond angles than PH3? |
> The cation Ag+(aq) and Hg2^2+ are in an aqueous solution. Their
> concentrations are 0.2 moldm^-3 in relation to each other. Find which
> cation precipitates first as its iodide when a solution of NaI is
> added gradually to the above solution
It is poorly worded question. All the author means that the ratio of... |
> The cation Ag+(aq) and Hg2^2+ are in an aqueous solution. Their
> concentrations are 0.2 moldm^-3 in relation to each other. Find which
> cation precipitates first as its iodide when a solution of NaI is
> added gradually to the above solution
It is a poorly worded question. The author means that the ratio of A... |
I was presented with the following compound and asked to comment on the splitting of the proton $\ce{H_a}$ in $\ce{^1H}$ NMR.
[![Molecule of concern][1]][1]
The question presented today was:
> What is the chemical shift (below) and splitting pattern for $\ce{H_a}$ up to and
including $\ce{^4J}$?
I rela... |
> The cation Ag+(aq) and Hg2^2+ are in an aqueous solution. Their
> concentrations are 0.2 moldm^-3 in relation to each other. Find which
> cation precipitates first as its iodide when a solution of NaI is
> added gradually to the above solution
It is a poorly worded question. The author means that the ratio of A... |
I [read][1] that brewed tea contains a relatively large concentration of Florine.
Florine can have negative health effects such as [Skeletal Fluorosis][2]
Tap water and especially [hard water][3] contains lots of Calcium ions.
Would Calcium and Florine bond to form [Calcium Fluoride][4]? I'm obviously not a ch... |
Does brewing tea with hard water reduce the amount of bioavailable fluorine? |
I am measuring the electrical conductivity of ( NaCl and CH3COONa solutions with concentration 0.9g/100 mL) with Temperature using conductivity meter
Theoretically the conductivity should decrease as the tempreture decrease
Unfortunately that is not happening
As you can see starte measuring at 85 c the conductiv... |
the oxidation state of E in Eo2 and Eo3 is +4 and +6 respectively ...then how can both of them be acidic ? |
Does calcium nitrate decahydrate dehydrate or decompose upon heating to 100 degrees celsius? |
Consider a sample of $\ce{Ca(NO3)2.10H2O}$. To remove water, I need to heat it to $\pu{100 ^\circ C},$ but will this high temperature decompose it or will I get the anhydrous salt? |
Does calcium nitrate decahydrate dehydrate or decompose upon heating to 100 degrees Celsius? |
Can someone pls tell me which one is it? Benzyl free radical has 4 resonance structures compared to allyl free radical which has only 2. More the resonance structures should mean more stable the radical.
But in the book I am referring it is writte... |
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