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Why does Birch reduction of naphthalene with isoamyl alcohol form tetralin instead of 1,4-dihydrodialin (as formed with C2H5OH)? |
Say I have a gas cylinder with nitrous oxide and cool it down to −78 °C with dry ice. Is there an endothermic process/reaction that would extract the remaining heat from $\ce{N2O}$ and bring it down by 10 °C to its boiling point of −88 °C? I know this could be done by using cryogenics like liquid nitrogen, but I want t... |
The usual way of solving such a problem is to write two half-equations, and make the sum of them, after multiplying each one by a factor so as to get the same number of electrons. Each equation is about one of the atoms that changes its oxidation number.
Let's start from the first such atom, iodine in the ion iodat... |
The usual way of solving such a problem is to write two half-equations, and make the sum of them, after multiplying each one by a factor so as to get the same number of electrons. Each equation is about one of the atoms that changes its oxidation number.
Let's start from the first such atom, iodine in the ion iodat... |
The usual way of solving such a problem is to write two half-equations, and make the sum of them, after multiplying each one by a factor so as to get the same number of electrons. Each equation is about one of the atoms that changes its oxidation number.
Let's start from the first such atom, iodine in the ion iodat... |
This has gotten me confused since long. Not all equations have clean half- reactions, some cations are in more than one compound while some anions are in some other compounds. Some reactions don't even have any charges and just look like normal equations (if you don't separate ions), should we just balance them like no... |
Consider the following equations:
\begin{align}
\ce{CO2(g) + H2O(l) &<=> H2CO3(aq)} &\quad K_{CO2} &= 10^{-1.47} \tag{1}\\
\ce{H2CO3(aq) &<=> H+(aq) + HCO3-(aq)} &\quad K_1 &= 10^{-6.35} \tag{2}\\
\ce{HCO3-(aq) &<=> H+(aq) + CO3^{2-}(aq)} &\quad K_2 &= 10^{-10.33} \tag{3}\\
\ce{CaCO3(s) &<=> Ca^{2+}(aq) + CO3^{... |
When one mole of a monoatomic ideal gas at 'T' (in Kelvin) undergoes adiabatic change under the constant external pressure of 1 atm, changes volume from 1 liter to 2 liters. The final temperature in Kelvin would be (in terms of 'T')?
I've tried using the Adiabatic equation: PV^(gamma) = Const. for gamma = Cp/Cv. And... |
How do we find the final temperature of a system undergoing an adiabatic change? |
>Question:<img src="https://i.stack.imgur.com/pEVCV.png">
It's solution is given as:
<img src="https://i.stack.imgur.com/7FdDC.png">
Now I don't understand which d$\pi$ electrons have been considered here. For example, in $\ce{Fe(CO)_5}$, according to this, number of d$\pi$ electrons would be 4. I cannot see ... |
The equation you tried to use is for an adiabatic *reversible* process, and this process is irreversible.
Here are some "leading questions" to help you solve this problem: For beginners, you know the initial pressure, the initial volume, and the number of moles. From the ideal gas law, what does this give you for ... |
$$\text{Bond order} = \frac{N(b) - N(a)}{2}$$
Where $N(b)$ is the number of electrons in bonding orbitals and $N(a)$ is the number of electrons in antibonding orbitals.
As in metal carbonyls, there is synergic effect during formation of the π back bond from metal to $\ce{CO}$, so $\ce{CO}$ accepts electrons in it... |
To make 100. mL of a solution that is 0.25 *M* in chloride ion, how many grams of magnesium chloride would you need to dissolve?
I had a few different approaches to this, but my most immediate thought was to think of each element (monoatomic or polyatomic) as a part of a larger compound. Therefore, molarity of the chl... |
Consider the following equations:
\begin{align}
\ce{CO2(g) + H2O(l) &<=> H2CO3(aq)} &\quad K_{\ce{CO2}} &= 10^{-1.47} \tag{1}\\
\ce{H2CO3(aq) &<=> H+(aq) + HCO3-(aq)} &\quad K_1 &= 10^{-6.35} \tag{2}\\
\ce{HCO3-(aq) &<=> H+(aq) + CO3^{2-}(aq)} &\quad K_2 &= 10^{-10.33} \tag{3}\\
\ce{CaCO3(s) &<=> Ca^{2+}(aq) + ... |
Consider the following equations:
\begin{align}
\ce{CO2(g) + H2O(l) &<=> H2CO3(aq)} &\quad K_{\ce{CO2}} &= 10^{-1.47} \tag{1}\\
\ce{H2CO3(aq) &<=> H+(aq) + HCO3-(aq)} &\quad K_1 &= 10^{-6.35} \tag{2}\\
\ce{HCO3-(aq) &<=> H+(aq) + CO3^{2-}(aq)} &\quad K_2 &= 10^{-10.33} \tag{3}\\
\ce{CaCO3(s) &<=> Ca^{2+}(aq) + ... |
I have been trying to figure out this question, and essentially if I assume that the only atoms that the vector touches are the starting and ending atoms, then I get 0.58. I am trying to find a more formal method for determining linear packing factor for any vector direction in a unit cell. Can someone explain how to d... |
To make 100. mL of a solution that is 0.25 *M* in chloride ion, how many grams of magnesium chloride would you need to dissolve?
I had a few different approaches to this, but my most immediate thought was to think of each element (monoatomic or polyatomic) as a part of a larger compound. Therefore, molarity of the c... |
There are quite a few approaches (ranging from empirical additive rules based on presence of functional groups to full blown *in silico* QM calculations) to predicting molecular properties such as UV<sub>max</sub> absorption or IR vibrational frequencies. While not perfect, they give a general ballpark range of what to... |
"How to verify that ethanol is infinitely soluble in water?".
You cannot do it because it is WRONG. And not because it is false for ethanol, it is simply plain wrong conceptually and mathematically.
Solubility is the ratio between the amount of the specified substance and the volume of the phase solution.
As for a... |
Is a mixture of NH<sub>4</sub>OH and NH<sub>4</sub>NO<sub>3</sub> a buffer solution?
I have seen some examples with NH<sub>4</sub>OH and NH<sub>4</sub>Cl but never NH<sub>4</sub>NO<sub>3</sub> |
Is this mixture a buffer solution? |
Is a mixture of $\ce{NH4OH}$ and $\ce{NH4NO3}$ a buffer solution?
I have seen some examples with $\ce{NH4OH}$ and $\ce{NH4Cl}$ but never $\ce{NH4NO3}$. |
A buffer is a mixture of a weak acid with the conjugate weak base.
> Is a mixture of $\ce{NH4OH}$ and $\ce{NH4NO3}$ a buffer solution? I have seen some examples with $\ce{NH4OH}$ and $\ce{NH4Cl}$ but never $\ce{NH4NO3}$.
Both mixtures contain $\ce{NH4+}$, a weak acid. Where is the conjugate weak base? You can eit... |
Is mixture of ammonium hydroxide and ammonium nitrate a buffer solution? |
Please note this question is different to the other that keeps being mentioned. That one is about the concentration of just $\ce{HCO3-}$ when no $\ce {pH} $ was given.
Whereas, in this one I am trying to find the concentrations of $\ce{H+}$, $\ce{HCO3-}$, $\ce{CO3^{2-}}$, and $\ce{Ca^2+}$.
Consider the following ... |
İ couldnt find much info on internet about solubility of glycerol in triglycerides.İ suppose its non soluble because glycerin is polar but fats arent but fats have glycerin side in them too so can they interact?
|
Does glycerin dissolve in fat? |
İ couldn't find much info on internet about solubility of glycerol in triglycerides. I suppose it is non soluble because glycerin is polar but fats aren't. But fats have glycerin side in them too, so can they interact?
|
I'm making a cooling beverage dispenser for carbonated drinks. The keg remains room temperature and the beverage rises through a pipe that's coiled up inside a cooling unit filled with water or alcohol.
My first choice would be copper tubing because of its conductive properties, but I remember reading somewhere th... |
Why does dilithium have a longer bond length than dihydrogen? |
Please note this question is different to the other that keeps being mentioned. That one is about the concentration of just $\ce{HCO3-}$ when no $\ce {pH}$ was given.
Whereas, in this one I am trying to find the concentrations of $\ce{H+}$, $\ce{HCO3-}$, $\ce{CO3^{2-}}$, and $\ce{Ca^2+}$, with a given $\ce {pH}$.
... |
With knowledge of ring strain, placing a double bond within a cyclopropane ring would increase the "angle strain" from $109.5 ^\circ$ to $120 ^\circ$ so are cyclopropenes stable? So far, I have only come across the famous aromatic cyclopropene cation but yet to see a neutral cyclopropene ring containing molecule. Howev... |
I am reading "Effect of Freeze-Drying on Quality and Grinding
Process of Food Produce": A Review
Timilehin Martins Oyinloye and Won Byong Yoon
The problem is they are refereing to the words "sold matrix" several times. I searched the internet but coud not understand what does that mean. Any comments please? Is th... |
What is solid matrix mean? |
When you add an inert gas to a container of constant volume full of gases, you are basically shoving the inert gas into the container and increasing the pressure inside the container, so the partial pressures of all the gases increase don't they? |
Doesn't adding an inert gas at constant volume increase the partial pressures? |
Why should they ( supposing ideal gas behaviour ) ?
If a volume, containing $\pu{4 mol}$ $\ce{N2}$ and $\pu{1 mol}$ $\ce{O2}$ has pressure $\pu{5 atm}$, partial pressures are:
$\ce{N2} : \pu{4 atm}$
$\ce{O2} : \pu{1 atm}$
If you add $\pu{5 mol}$ $\ce{Ar}$, the total pressure raises to $\pu{10 atm}$, ... |
What does solid matrix mean? |
$K_m$ is the Michaelis constant, which is the concentration of substrate needed to achieve a rate of $\frac{V_{max}}{2}$. $V_{max}$ is the maximum number of molecules that can be reacted per second.
[![enter image description here][1]][1]
My lecturer has said that $K_m$ is the lowest concentration of substrate ne... |
Why is Km the concentration needed to keep the enzyme running at max speed? |
> $K_m$ is the lowest concentration of substrate needed to ensure that the system runs at $V_{max}$?
No. $V_{max}$ is never reached, it is the limit of the rate when you increase the substrate concentration indefinitely. Less dramatically said, when the substrate concentration is about ten time higher than $K_m$, th... |
Is Km the concentration needed to keep the enzyme running at max speed? |
> $K_m$ is the lowest concentration of substrate needed to ensure that the system runs at $V_{max}$?
No. $V_{max}$ is never reached, it is the limit of the rate when you increase the substrate concentration indefinitely. Less dramatically said, when the substrate concentration is about ten time higher than $K_m$, th... |
> $K_m$ is the lowest concentration of substrate needed to ensure that the system runs at $V_{max}$?
No. $V_{max}$ is never reached, it is the limit of the rate when you increase the substrate concentration indefinitely. Less dramatically said, when the substrate concentration is about ten times higher than $K_m$, t... |
> $K_m$ is the lowest concentration of substrate needed to ensure that the system runs at $V_{max}$?
No. $V_{max}$ is never reached, it is the limit of the rate when you increase the substrate concentration indefinitely. Less dramatically said, when the substrate concentration is about ten times higher than $K_m$, t... |
So this is actually a problem I got to do as homework for school. Basically, it states (translating from another language, please ignore any grammar problems):
> A gas X2O5 has a density of 5 g/L in STP. What is the atomic mass of X? Given: Ar: O = 16.
I solved, or at least tried to, by doing this:
ρ = m/V... |
I am reading "Effect of Freeze-Drying on Quality and Grinding
Process of Food Produce": [A Review by Timilehin Martins Oyinloye and Won Byong Yoon](https://doi.org/10.3390/pr8030354).
The problem is they are referring to the words "sold matrix" several times. I searched the internet but could not understand what d... |
I'm having trouble wrapping my head around Kohlrausch law of infinite dilution and molar conductivities in general.
For a salt ,let's say $A^+B^-$ ,the molar conductivity at infinite dilution can be expressed as the sum of molar conductivities at infinite dilution of the respective elements.
$$\lambda^o_{AB}=\lam... |
How exactly does electrolysis occur if the molar conductivities of cation and anion are different? |
**NOTE:** The problem is probably missing something, or it was written with wrong information from where I picked it up. Just leaving, though, it as a cautionary tale to anyone who might also have it.
So this is actually a problem I got to do as homework for school. Basically, it states (translating from another lan... |
**NOTE:** The problem is probably missing something, or it was written with wrong information from where I picked it up. Just leaving, though, it as a cautionary tale to anyone who might also have it.
So this is actually a problem I got to do as homework for school. Basically, it states (translating from another lan... |
I'm having trouble wrapping my head around Kohlrausch law of infinite dilution and molar conductivities in general.
For a salt $\ce{AB}$ the molar conductivity at infinite dilution can be expressed as the sum of molar conductivities at infinite dilution of the respective elements.
$$\Lambda^\circ_\mathrm{m}(\ce{A... |
I am currently studying *Diode Lasers and Photonic Integrated Circuits*, second edition, by Coldren, Corzine, and Mashanovitch. In chapter **1.2 ENERGY LEVELS AND BANDS IN SOLIDS**, the authors say the following:
> On the other hand, in a covalently bonded solid like the semiconductor materials we use to make diode ... |
What does "spin degeneracy" mean in this context? |
The $\sqrt K/\sqrt C$ ratio is only an approximation. Let's do something more exact. (Why do I say "more exact" instead of "completely exact"? Read on, nature has a nasty curveball in store for us!)
Let $C$ be the nominal concentration of the acid, assumed monoprotic ($\ce{HA}$) for simplicity, and $K$ be its dis... |
My broad question is how do you measure entropy change? I was doing a bit of digging into how thermodynamic tables are developed at I [got this][1] from NIST. Basically it seems like you need to indirectly determine the entropy of a substance from other experimental parameters. What NIST says is
1. You use heat cap... |
Is it possible to measure the entropy of a chemical reaction through calorimetry? |
I've been learning how to simulate a 1M phosphoric acid titration curve using numerical methods in R.
So far has this has been the best curve:
[![enter image description here][1]][1]
Notice how it flattens out (artificially) towards the left.
I am not certain if this is a programming and/or a "chemistry" is... |
There is a reaction that confused me a bit:
[![Reaction with SeCl4][1]][1]
According to my research on $\ce{SeCl4}$, it can be used as a dichlorinating agent for alkenes. However, I am totally confused about the mechanism. I've read about several mechanisms using $\ce{PhSe-SePh}$ as a precatalyst, but in this rea... |
Of [Cd(NH2CH3)4]2+ and [Cd(en)2]2+ the stability of the latter is higher than the former attributing to chelation in the en complex .This is evident from the fact that the Gibbs Free Energy change for the latter is -60.7kJ/mol whereas for the former it is -37.2 kJ/mol.
But the entropy values do not all provide any c... |
Of [Cd(NH2CH3)4]2+ and [Cd(en)2]2+ the stability of the latter is higher than the former attributing to chelation in the en complex .This is evident from the fact that the Gibbs Free Energy change for the latter is -60.7kJ/mol-1 whereas for the former it is -37.2 kJ/mol-1.
But the T*deltaS do not all provide any cor... |
I need to simulate a salt diluted in a liquid electrolyte.
My experience is with LAMMPS, but so far I only had coarse grained toy models, and setting up the force field was straightforward.
Now I have a real molecule (>20 atoms), which I optimized quantum mechanically with MP2 and I have tried to run various tools to... |
What is the most appropriate (and easy-to-use) all-atoms force field for liquid electrolytes? |
I am currently studying *Diode Lasers and Photonic Integrated Circuits*, second edition, by Coldren, Corzine, and Mashanovitch. In chapter **1.2 ENERGY LEVELS AND BANDS IN SOLIDS**, the authors say the following:
> On the other hand, in a covalently bonded solid like the semiconductor materials we use to make diode ... |
What precisely is the author referring to here when he says "upper half" and "lower half" of "the energy band"? What is "the energy band"? |
I am currently studying *Diode Lasers and Photonic Integrated Circuits*, second edition, by Coldren, Corzine, and Mashanovitch. In chapter **1.2 ENERGY LEVELS AND BANDS IN SOLIDS**, the authors say the following:
> On the other hand, in a covalently bonded solid like the semiconductor materials we use to make diode ... |
Is the case of the linear chain of atoms one-dimensional? |
> A gas $\ce{X2O5}$ has the density of $\pu{5 g L-1}$ at STP. What is the atomic mass of $\ce{X}$ given $A_\mathrm{r}(\ce{O}) = 16?$
**Note:** The problem is my homework for school and has been translated from another language. It is probably either missing something or it contains wrong data. Just leaving it as a c... |
> A gas $\ce{X2O5}$ has the density of $\pu{5 g L-1}$ at STP. What is the atomic mass of $\ce{X}$ given $A_\mathrm{r}(\ce{O}) = 16?$
**Note:** The problem is my homework for school and has been translated from another language. It is probably either missing something or it contains wrong data. Just leaving it as a c... |
Given an EPR spectrum of [Co(3-methoxysalen)(py)] :
[![EPR spectrum of [Co(3-methoxysalen)(py)]][1]][1]
and equations:
A(x) = A(iso) + B
A(z) = A(iso) - 2B
%Co in SOMO = B/B0
where A(x) and A(z) are hyperfine coupling constants measured from the spectrum and B0 = 7.6 mT, we have to calculate %Co. This ... |
Can % location of electron on metal or ligand be negative (EPR)? |
Rotation of groups about double bonds are usually restricted due to large torsional strain and it is due to this reason that cis and trans isomers have their independent existence. However, certain structural modifications in the compound makes the rotation of groups about double bond possible and hence, for such compo... |
> Rotation of groups about double bonds are usually restricted due to large torsional strain and it is due to this reason that *cis*- and *trans*-isomers have their independent existence. However, certain structural modifications in the compound makes the rotation of groups about double bond possible and hence, for suc... |
I came across this fact while reading my book and was confused. Looking at the structures, I had the intuition that benzoic acid would be more acidic as the conjugate base formed will resonate all over the benzene ring.
Why does this happen? |
Why is Oxalic acid more acidic than benzoic acid? |
Why is oxalic acid more acidic than benzoic acid? |
My lecturer told me that 2° and 3° alcohols prefer to dehydrate through E-1 mechanism. On the other hand, 1° alcohols tend to prefer the E-2 mechanism, which does not involve the formation of a carbocation intermediate, and thus rues out scope for rearrangement.
This is backed by online sources:
> **Primary alcoh... |
My lecturer told me that 2° and 3° alcohols prefer to dehydrate through E-1 mechanism. On the other hand, 1° alcohols tend to prefer the E-2 mechanism, which does not involve the formation of a carbocation intermediate, and thus rues out scope for rearrangement.
This is backed by online sources:
> **Primary alcoh... |
Do all group 13 elements react with nitrogen to form nitrides of form `MN` ? <br>
JDLEE inorganic chemistry book mentions the following
> Aluminium burns in dinitrogen at high temperatures forming AlN. The other elements do not react
However is does mention react of boron with nitrogen elsewhere, `B + N2 --> B... |
Is it that every liquid we see is water, with more or less of x substance?
Example: urine is water with salt and minerals |
Are most liquids water-based? |
Do all group 13 elements react with nitrogen to form nitrides of form $\ce{MN}?$ <br>
J.D. Lee's *Inorganic chemistry* book mentions the following:
> Aluminium burns in dinitrogen at high temperatures forming $\ce{AlN}.$ The other elements do not react.
However, a reaction of boron with nitrogen is mentioned e... |
Given Fischer's projections of a few stereoisomers of some compound, how can we find out if they are enantiomers, diastereomers, etc.? From what I understand, we can rotate the projections to have the same groups on the top and bottom and then compare (non-superimposable mirror images --> enantiomers, non-mirror image ... |
I've been learning how to simulate a 1M phosphoric acid titration curve using numerical methods in R.
So far has this has been the best curve:
[![enter image description here][1]][1]
Notice how it flattens out (artificially) towards the left.
I am not certain if this is a programming and / or a "chemistry" ... |
Why would substitution of H with D alter chemical shift? |
The eMolecules page for example offers a [complete dataset](https://downloads.emolecules.com/free/2021-03-01/) containing ~26 mio structures. They're providing it either as 300 MB SMILES archive or 6 GB SDF archive (1.5GB and 50GB uncompressed respectively).
Does the SDF file contain any information about the chemic... |
Does the SDF format has any benefit over SMILES? |
I recently came across a question which asked me to find out which metal hydroxides are soluble in excess NaOH solution.
[![The question][1]][1]
[1]: https://i.stack.imgur.com/5f9jw.png
Is there any way to determine rationally which of these hydroxides will be soluble or should I rely on remembering them ... |
I recently came across a question which asked me to find out which metal hydroxides are soluble in excess $\ce{NaOH}$ solution.
Number of hydroxides which are soluble in excess of $\ce{NaOH}$ among the following given hydroxide?
$\ce{Al(OH)3, Zn(OH)2, Cr(OH)3, Pb(OH)2, Mn(OH)2, Fe(OH)3, Ni(OH)2, Sn(OH)2.}$
Is ... |
The eMolecules page for example offers a [complete dataset](https://downloads.emolecules.com/free/2021-03-01/) containing ~26 mio structures. They're providing it either as 300 MB SMILES archive or 6 GB SDF archive (1.5GB and 50GB uncompressed respectively).
Does the SDF file contain any information about the chemic... |
> Rotation of groups about double bonds are usually restricted due to large torsional strain and it is due to this reason that *cis*- and *trans*-isomers have their independent existence. However, certain structural modifications in the compound makes the rotation of groups about double bond possible and hence, for suc... |
I am reading the Joule-Thomson experiment and although I can follow the mathematics I can't understand what is going on. Here is the apparatus
... |
> Given that the standard potential for a fuel cell is 1.229 V what is causing the difference in our measurement?
Multiple sources (e.g. [here][1], [here][2] and [there][3]) estimate the voltage to be much less than the standard potential, especially when there is a load.
> Individual fuel cells produce relative... |
>**OP's main question:** Why would substitution of $\ce{H}$ with $\ce{D}$ alter chemical shift?
OP has correctly indicated that the $\ce{Sn-D}$ bond will be shorter/stronger than $\ce{Sn-H}$ due to the lower ZPE, which may cause the chemical shift difference. That is the major reason for isotope effect in chemical k... |
>**OP's main question:** Why would substitution of $\ce{H}$ with $\ce{D}$ alter chemical shift?
OP has correctly indicated that the $\ce{Sn-D}$ bond will be shorter/stronger than $\ce{Sn-H}$ due to the lower ZPE, which may cause the chemical shift difference. That is the major reason for isotope effect in chemical k... |
I've been looking for an answer for this for quite a bit but I'm still quite confused. On the independence from ml, I think that it originates from the symmetry of the molecule. However, the independence from l, is what confuses me. Others have mentioned that it is due to the fact that the potential energy is purely Co... |
Why is the energy levels in hydrogen independent of the quantum numbers l and ml? |
>**OP's main question:** Why would substitution of $\ce{H}$ with $\ce{D}$ alter chemical shift?
OP has correctly indicated that the $\ce{Sn-D}$ bond will be shorter/stronger than $\ce{Sn-H}$ due to the lower ZPE, which may cause the chemical shift difference. That is the major reason for isotope effect in chemical k... |
>**OP's main question:** Why would substitution of $\ce{H}$ with $\ce{D}$ alter chemical shift?
OP has correctly indicated that the $\ce{Sn-D}$ bond will be shorter/stronger than $\ce{Sn-H}$ due to the lower ZPE, which may cause the chemical shift difference. That is the major reason for isotope effect in chemical k... |
I was reading about $pK_a$ values of 2-Fluorobenzoic acid and 4-Fluorobenzoic acid and found that the latter had lower value which was surprising to me as I think that intramolecular hydrogen bonding should dominate all the other effects in 2-Fluorobenzoic acid as mentioned in the following figure.<br/>
So I wanted to... |
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