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I recently started learning about quantum mechanics and its applciations in atomic structure in chemistry.
In this inorganic textbook [Inorganic Chemistry][1], it describes
"Each of the wavefunctions obtained by solving the Schrödinger equation for a hydrogenic
atom is uniquely labelled by a set of three integ... |
For the reaction: $$\ce{P4(s) + 5O2(g) <=> P4O10(s)}$$
Let's say the reaction is at equilibrium, and SOME $\ce{P4O10(s)}$ is removed from the reaction. Will that affect equilibrium? My assumption is no, since $\ce{P4O10(s)}$ is not included in the equilibrium expression.
However, for me, it gets confusing when le... |
I have bought iodine about a year ago but the bottle cap got damaged during the transportation and it leaked all over the package, but I have decided to keep it anyway. Unfortunately I did not use it to anything and it was just sitting on my shelf with cracked cap with about a one millimetre sized hole.
I wonder if ... |
How long can iodine bottle left open? Can it go bad sooner than expiration date? |
I was wondering why the state where electrons are evenly (or the closest to being evenly) distributed among the atoms in a molecule is not the lowest energy state? For example, in a water molecule it is known that oxygen attracts electrons from hydrogen due to its high electronegativity (oxygen wants to fill its shell)... |
Why electrons do not distribute evenly among the atoms in a molecule? |
From 'Leighton relationship' on Wikipedia:
through the following mechanism:[2]
NO2 + hν (λ < 420 nm) → NO + O (3P)
(J1)
O (3P) + O2 + M → O3 + M
(k2)
NO + O3 → NO2 + O2
(k3)
This series of reactions creates a null cycle, in which there is n... |
In reaction equations, why are j and k sometimes capitalized to J and K? |
A solution of iodine antiseptic is a medical item that is used for improving health. There are two ways to treat your cracked cap.
#1. If you inspected the bottle in the drug store before you bought it, you would not buy this bottle. Almost all over-the-counter medicines have warnings: Do not use if the safety seal ... |
From 'Leighton relationship' on Wikipedia:
through the following mechanism:[2]
NO2 + hν (λ < 420 nm) → NO + O (3P)
(J1)
O (3P) + O2 + M → O3 + M
(k2)
NO + O3 → NO2 + O2
(k3)
This series of reactions creates a null cycle, in which there is n... |
I have been studying thermodynamics for quite a time now, and recently learned about enthalpy
but I have been facing a lot of problems
So,which is the correct equation of enthalpy
$$\Delta H=\Delta U+\Delta (PV)$$
or
$$\Delta H=\Delta U+P\Delta V$$
or
$$\Delta H=\Delta U+W$$
I am facing issue... |
### The hydrogen atom
Indeed, three numbers cannot define a function. There are several more criteria, one of which you mentioned already: it must satisfy the time-independent Schrödinger equation. The Schrödinger equation is a nasty differential equation, which looks something like the following:
$$-\frac{\hbar^... |
While qualitatively comparing the acidic nature of <i>o</i>-methyl benzoic acid and benzoic acid, we consider the steric effect due to which the $\ce{-COOH}$ group loses its planarity and the +M effect of $\ce{-CH3}$ isn't considered any longer. But still, the +I of $\ce{CH3}$ is functioning, which increases the electr... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/HBzBQ.png
Why are they taking delta H in equation (iv) to be at constant pressure while in the same equation they are considering delta E to be at constant volume to arrive at equation (v)? If they are arriving at equation (iv) from equati... |
# Preamble
One important thing to know is that what we call "resonance structure" is a byproduct of our chemical notation which can't describe the structure of some compounds effectively using only one chemical structure. Personally I find the old term **mesomeric structure** more appropriate (*meso-* Greek mésos in... |
**Synopsis**
We are given a proposed mechanism for the condensation of $\ce{(CH_3)_2CO}$ as follows
First Step: $$\ce{(CH_3)_2CO + OH^- <=> CH_3C(O)CH_2^- + H_2O}$$
Second Step: $$\ce{CH_3C(O)CH_2^- + (CH_3)_2CO -> Product}$$
**Attempt and Question**
I assume $\ce{CH_3C(O)CH_2^-}$ is in steady-state, and o... |
I think you can look at this entirely from the perspective of entropy (forget about the Gibbs free energy for a moment). You can divide the universe into two parts, the system and its surroundings.
When a change happens in your system, and some heat is exchanged with the surroundings then the change in entropy of th... |
I know EFFECTIVE ATOMIC NUMBER (EAN) as the following
• The sum of the number of electrons, donated by all ligands and those present on the central metal ion or atom in the complex is called an effective atomic number (EAN).
EAN = [(atomic number of central metal) – (the oxidation state of the metal) + (the numbe... |
Is it possible to reduce aluminum hydroxide to aluminum metal by using a sacrificial magnesium electrode in a single displacement reaction?
I checked my revision of redox charts and it looks like it should work.
For more detail, consider: $\ce{Al}$ is very fond of bonding with oxygen. It's such a strong reaction ... |
Is it possible to reduce aluminum hydroxide to aluminum metal by using a sacrificial magnesium electrode in a single displacement reaction?
I checked my revision of redox charts and it looks like it should work.
For more detail, consider: $\ce{Al}$ is very fond of bonding with oxygen. It's such a strong reaction ... |
In Perkin's reaction, an aromatic aldehyde reacts with an acid anhydride to give an alpha-beta unsaturated aromatic acid. Which reactant is the electrophile and which one is the nucleophile? |
What is the electrophile in Perkin's condensation reaction? |
I have bought iodine about a year ago but the bottle cap got damaged during the transportation and it leaked all over the package, but I have decided to keep it anyway. Unfortunately I did not use it to anything and it was just sitting on my shelf with cracked cap with about a one millimetre sized hole.
I wonder if ... |
I have been learning thermodynamics for quite a time and I fail to relate Gibbs free energy and stability
for example i have couple oxides like
$$ 1.ZnO (ΔG° = - 318.4, ΔH° = - 348.3)$$
$$ 2.Cu2O(ΔG° = - 146.0, ΔH° = - 168.8)$$
$$ 3.HgO (ΔG° = - 58.5, ΔH° = - 90.8)$$
$$ 4.PbO (ΔG° = - 187.9, ΔH° = - 217.3)$$
... |
how is gibbs free energy related to stability? |
I have been learning thermodynamics for quite some time and I fail to relate Gibbs free energy and stability.
For example, how do I compare stability of metal oxides using the following data?
Also, do stable compounds decompose easily or hard?
$$
\begin{array}{clrr}
\hline
\text{#} & \text{Compound} & \Delta... |
How is Gibbs free energy related to stability? |
I was recently studying organic chemistry related to Isomerism. I have doubt based on an example that is,
1. Why Cumulenes show GI?
2. Why 1-chloro cyclohexane don't show GI? |
Why these compounds don't show and show Geometrical isomerism? |
250 mL of a waste solution obtained from the workshop of a goldsmith contains 0.1 M AgNO3 and 0.1 M AuCl. The solution was electrolyzed at 2 V by passing a current of 1 A for 15 minutes. The metal/metals electrodeposited will be:-
(1) only silver
(2) only gold
(3) silver and gold in equal mass proportion
(4) ... |
What happens when solution containing two or more cations are electrolysed at an excess potential? |
> TL;DR: Do **not** just memorise thermodynamics equations! And if you have an issue with the equations $\Delta U = 0$ or $\Delta H = 0$ for an isothermal process, read on...
---------
### The first problem
You said that an exothermic reaction corresponds to $\Delta U < 0$. This is not true. It is defined by $... |
The doubt in my mind is that the electron withdrawing group is attached to the carbon atom of the carbonyl group and that carbon doesn't have any negative charge..the negative charge lies on oxygen atom so how does this electron withdrawing group pulls the electron from oxygen.? |
Why does the electron withdrawing group increase acidic nature of carboxylic acids? |
From 'Leighton relationship' on Wikipedia:
through the following mechanism:[2]
($J_1$) $$\ce{NO2 + h\nu (\lambda < 420 nm) → NO + O (^3P)}$$
($k_2$) $$\ce{O (^3P) + O2 + M → O3 + M}$$
($k_3$) $$\ce{NO + O3 → NO2 + O2}$$
This series of reactions creates a null cycle, in which there is no net production... |
>[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/TyUoU.png
From the rules that I know, I will name the above compound as $3$-propyl-penta-$1,3$-diene because maximum number of functional groups (double bonds in this case) are in the five numbered ring.
However chemdraw names the abov... |
>[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/TyUoU.png
From the rules that I know, I will name the above compound as 3-propyl-penta-1,3-diene because maximum number of functional groups (double bonds in this case) are in the five numbered carbon chain.
However chemdraw names the ... |
I was recently studying organic chemistry related to Isomerism. I have doubt based on an example that is,
1. Why Cumulenes show GI?
2. Why 1-chloro cyclohexene don't show GI? |
I'm troubleshooting an IHC staining issue, and according to Thermo-Fischer's website, "Deionized water can sometimes contain peroxidase inhibitors that can significantly impair enzyme activity." What exactly could deionized water contain that would inhibit peroxidase? |
How can DI water inhibit peroxidase activity? |
Today I was using my pH meter on wastewater samples but the meter was reading values near 14 and sometimes greater, I changed the probe with the spare one and it read well (sure I calibrated before reading) My question is if the probe must be damaged or is it only need cleaning? |
im trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of CO, H20 and N2. Only CO is unwanted in this case. Could i use calcium hydroxide to scrub carbon monoxide out of the gas? what other substances could be effective? |
what chemical could be used as carbon monoxide scrubbers? |
im trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of $\ce{CO, H20}$ and $\ce{N2}$. Only $\ce{CO}$ is unwanted in this case. Could i use calcium hydroxide to scrub carbon monoxide out of the gas? what other substances could be effective? |
im trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of $\ce{CO, H2O}$ and $\ce{N2}$. Only $\ce{CO}$ is unwanted in this case. Could i use calcium hydroxide to scrub carbon monoxide out of the gas? what other substances could be effective? |
> Although the phenolate ion has more resonance structures (4) compared to acetate ion (2), acetate is more stable because it has two equivalent resonance structures of same energy.
I would argue the phenolate ion has five mesomeric structures, two with the charge assigned to oxygen (analogous to the two resonance s... |
The answer to this question is actually pretty interesting, I think. @user55119 's comment that the principal chain is the cyclohexane ring is correct -- but it seems like you understand that that's what the teacher is saying, and you're asking, "why?" The best short answer, too, is imho in your comments: @MaxW 's "n... |
**Please edit the table to include missing data**
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
| Edition | Years(s) | page | value | CODATA? |
|---------|-----------|-------|--------------|-------------------|
| 1 [(Link)](https://books.google.com/books?id=07AHIEp6vYQC&printse... |
The answer to this question is actually pretty interesting, I think. @user55119 's comment that the principal chain is the cyclohexane ring is correct -- but it seems like you understand that that's what the teacher is saying, and you're asking, "why?" The best short answer, too, is imho in your comments: @MaxW 's "n... |
The answer to this question is actually pretty interesting, I think. @user55119 's comment that the principal chain is the cyclohexane ring is correct -- but it seems like you understand that that's what the teacher is saying, and you're asking, "why?" The best short answer, too, is imho in your comments: @MaxW 's "n... |
You did not mention what kind of waste water are you talking about. Is it from a textile industry, paper mill, leather factory? Waste water is not a "compound", it can be any junk and its pH can vary over several orders of magnitude!
As I have stated before, there is nothing fundamental about pH. It is a scale of co... |
The reaction that I did is shown below. I'm testing the duration and luminosity of the light the reaction produces against different pH. The way I used to control the pH is by adding more or less Na2CO3 since it is basic with a pH of 11.
Solution A: In 200ml water, add in 0.16g Na2CO3, 0.04g luminol, 5g NaHCO3, 4.6g... |
Does anybody have any ideas about the trend that I found for luminol chemiluminescence reaction? Or can anybody help me analyze them? |
Why does boron have a lower affinity than oxygen? |
why is para aminobenzoic acid more acidic than ortho aminobenzoic acid? |
I know this has been asked before, but can anyone explain me in simpler terms. Why is $CO_{2}$ a lewis acid, the carbon atom doesn't have any vacant orbitals to accept lone pair, then how can it be a lewis acid? |
Why is $CO_{2}$ a lewis acid? |
You did not mention what kind of waste water are you talking about. Is it from a textile industry, paper mill, leather factory? Waste water is not a "compound", it can be any junk and its pH can vary over several orders of magnitude!
As I have stated before, there is nothing fundamental about pH. It is a scale of co... |
Recently I did an experiment using graphite as the anode and iron as the cathode for an electrolytic cell. I tried plating different metals such as copper, nickel, and zinc with CuSO4, NiSO4, and ZnSO4 respectively. I know that normally when the anode is made from the same material as the metal being used for plating, ... |
What happens at the inert anode in an electrolytic cell? |
I know this has been asked before, but can anyone explain me in simpler terms? Why is $\ce{CO2}$ a Lewis acid? The carbon atom doesn't have any vacant orbitals to accept a lone pair. How can it be a Lewis acid? |
Why is carbon dioxide a Lewis acid? |
I am looking for an alternative to the sodium acetate reaction used in e.g. heat packs. I need something similiar but that generates more heat, so that I could for instance warm 200ml of water to a temperature of 37 °C.
So is their any *safe* and *reusable* reaction as used in heat packs but that generates more heat... |
I am looking for an alternative to the sodium acetate reaction used in e.g. heat packs. I need something similiar but that generates more heat, so that I could for instance warm 200ml of water to a temperature of 37 °C.
So is their any *safe* and *reusable* reaction as used in heat packs but that generates more heat... |
_____________________________
Operatively:
A plane of symmetry in a 2-D projection of a cyclohexane is a sufficient condition.
Alternatively, and lengthy, you conduct an analysis involving conformers but *not limited to the flipping of the ring*, that means you must let the chloromethyl rotate, in your example.
______... |
Electrochemistry cells and emf
A cell is set up with copper and lead electrodes in contact with CuSO4(aq) and Pb(NO3)2(aq), respectively, at 25˚C. The standard reduction potentials are:
Pb2+ + 2e- --> Pb E˚= -0.13 V
Cu2+ + 2e- --> Cu E˚= +.34 V
If sulfuric acid is added to the Pb(NO3)2 solution, forming a p... |
Can HF vapor be released from NH4F water solution? |
Ammonium bifluoride or ammonium hydrogen fluoride is a salt of a weak base and strong acid.
The strong acid is because the second equilibria of HF written as HF + F- <-> HF2- and it has constant of 3.963 M.
But does the bifluoride anion further dissociate?
HF in water has many species H+, F-, HF2-, H2F2 and (... |
Does ammonium bifluoride in water dissociate to NH4+ and HF2-? |
Ammonium bifluoride or ammonium hydrogen fluoride is a salt of a weak base and strong acid.
The strong acid is because the second equilibria of $\ce{HF}$ written as:
$$\ce{HF + F- <=> HF2-}$$
and it has constant of $\pu{3.963 M}$.
But does the bifluoride anion further dissociate?
$\ce{HF}$ in water ha... |
Can $\ce{HF}$ vapors be released from $\ce{NH4F}$ solution in water $(w(\ce{NH4F}) = 40\,\%)$ at room temperature?
I assume that dissolving $\ce{NH4F}$ in water produces small amount of $\ce{HF}.$ |
Does aqueous ammonium fluoride solution release hydrogen fluoride vapors? |
> A cell is set up with copper and lead electrodes in contact with $\ce{CuSO4(aq)}$ and $\ce{Pb(NO3)2(aq)},$ respectively, at $\pu{25 °C}.$ The standard reduction potentials are:
>
> $$
\begin{align}
\ce{Pb^2+ + 2 e- &-> Pb} &\quad E^\circ &= \pu{-0.13 V} \\
\ce{Cu^2+ + 2 e- &-> Cu} &\quad E^\circ &= \pu{+0.34 V}
... |
How does precipitate affect cell potential? |
Ammonium bifluoride or ammonium hydrogen fluoride is a salt of a weak base and strong acid.
The strong acid is because the second equilibria of $\ce{HF}$ written as:
$$\ce{HF + F- <=> HF2-}$$
and it has constant of $\pu{3.963 M}$.
But does the bifluoride anion further dissociate?
$\ce{HF}$ in water ha... |
Ammonium bifluoride or ammonium hydrogen fluoride is a salt of a weak base and a weak acid.
The weak acid is because the second equilibria of $\ce{HF}$ written as:
$$\ce{HF + F- <=> HF2-}$$
and it has constant of $\pu{3.963 M}$.
But does the bifluoride anion further dissociate?
$\ce{HF}$ in water has ... |
> A cell is set up with copper and lead electrodes in contact with $\ce{CuSO4(aq)}$ and $\ce{Pb(NO3)2(aq)},$ respectively, at $\pu{25 °C}.$ The standard reduction potentials are:
>
> $$
\begin{align}
\ce{Pb^2+ + 2 e- &-> Pb} &\quad E^\circ &= \pu{-0.13 V} \\
\ce{Cu^2+ + 2 e- &-> Cu} &\quad E^\circ &= \pu{+0.34 V}
... |
At low concentrations of NH4HF2, like 1-2 wt%, the pH in a water solution is about 3.
But the NH4F has a pH of about 7 in 20-40 wt% concentration in water.
Yet the equilibria of
HF -> H+ + F- K=6.85 x 10-6 M (1)
HF + F- -> HF2- K=3.963 M (2)
I understand that NH4F comes from a weak acid and a weak base. So... |
Why is the solution of NH4HF2 more acidic than NH4F in water? |
At low concentrations of $\ce{NH4HF2}$, like $1-2$ wt%, the pH in a water solution is about $3$.
But the $\ce{NH4F}$ has a pH of about $7$ in $20-40$ wt% concentration in water.
Yet the equilibria of
$\ce{HF -> H+ + F- ; K = 6.85 x 10^{-6} M} ... (1) $
$\ce{HF + F- -> HF2- ; K = 3.963 M^{-1}} .... (2)$
I ... |
At low concentrations of NH4HF2, like 1-2 wt%, the pH in a water solution is about 3.
But the NH4F has a pH of about 7 in 20-40 wt% concentration in water.
Yet the equilibria of
HF -> H+ + F- K=6.85 x 10-6 M (1)
HF + F- -> HF2- K=3.963 M (2)
I understand that NH4F comes from a weak acid and a weak base. So... |
At low concentrations of aqueous $\ce{NH4HF2}$ $(w = 1–2\,\%)$ $\mathrm{pH}\approx 3.$
But aqueous $\ce{NH4F}$ $(w = 20–40\,\%)$ has $\mathrm{pH}\approx 7.$
Yet the equilibria of
$$
\begin{align}
\ce{HF &-> H+ + F-} &\quad K &= \pu{6.85E-6 M} \tag{1} \\
\ce{HF + F- &-> HF2-} &\quad K &= \pu{3.963 M^-1} \ta... |
Why is the solution of ammonium bifluoride more acidic than aqueous ammonium fluoride? |
[![enter image description here][1]][1]
[![enter image description here][2]][2]
I have re-read the Electrochemistry chapter from my textbook just now to remind my self of the exact formulae. I still don't understand how to approach this question, however - how can we work it out? I can either give you the mark ... |
I am trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of $\ce{CO},$ $\ce{H2O}$ and $\ce{N2}.$ Only $\ce{CO}$ is unwanted in this case.
Could I use calcium hydroxide to scrub carbon monoxide out of the gas? What other substances could be effective? |
What chemical could be used as carbon monoxide scrubber? |
During an addition reaction of an alkene, how does a double bond break to form two bonds with the two atoms of the reactant plus a bond between the carbon atoms? Not sure if this is a silly question or not, but if it’s a double bond, how does it end up forming three bonds? |
>According to the UK proof standard, a 100 proof spirit was defined as a spirit with gravity of $\frac{12}{13}$ that of water or $\pu{923 kg m-3}$, which is equivalent to $\mathrm{57.15\% \ ABV}$.
One liter of $\mathrm{57.15\% \ ABV}$ spirit contains $\pu{571.5 cm3}$ ethanol and $\pu{428.5 cm3}$ water. If the densit... |
Why does a 57.15% ABV spirit (ethanol+water) have a density of 923 kg per cubic meter? |
I am trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of $\ce{CO},$ $\ce{H2O}$ and $\ce{N2}.$ Only $\ce{CO}$ is unwanted in this case.
Could I use calcium hydroxide to scrub carbon monoxide out of the gas? What other substances could be effective?
edit: this is part of ... |
I have been given a problem to derive a relation for change in entropy from change in Gibbs free energy.
Starting with the isothermal equation
$$G(p_2) = G(p_1) + nRT \ln(\frac{p_2}{p_1})\tag{1}$$
derive
$$S(V_2) = S(V_1) + nR \ln(\frac{V_2}{V_1})\tag{2}$$
using the relation $$\begin{align}
dG & = Vdp -SdT\tag{3}... |
$\pu{250 mL}$ of a waste solution obtained from the workshop of a goldsmith contains $\pu{0.1 M}$ $\ce{AgNO3}$ and $\pu{0.1 M}$ $\ce{AuCl}$. The solution was electrolyzed at $\pu{2 V}$ by passing a current of $\pu{1 A}$ for 15 minutes. The metal/metals electrodeposited will be:<br>
(1) only silver
(2) only gold
... |
> $\pu{250 mL}$ of a waste solution obtained from the workshop of a goldsmith contains $\pu{0.1 M}$ $\ce{AgNO3}$ and $\pu{0.1 M}$ $\ce{AuCl}$. The solution was electrolyzed at $\pu{2 V}$ by passing a current of $\pu{1 A}$ for 15 minutes. The metal/metals electrodeposited will be:
>
> (1) only silver
> (2) only gol... |
The reaction that I did is shown below. I'm testing the duration and luminosity of the light the reaction produces against different pH. The way I used to control the pH is by adding more or less $\ce{Na2CO3}$ since it is basic with a pH of 11.
Solution A: In $\pu{200 ml}$ water, add in $\pu{0.16 g}$ $\ce{Na2CO3}$, ... |
### Problem
> How can we qualitatively compare the bond lengths between $\ce{H2O2}$ and $\ce{O2^2-}?$
### Answer
>! Bond length in $\ce{O2^2-}$ is slightly larger than in $\ce{H2O2}.$
### Attempt
I tried using molecular orbital theory, but since both have peroxide $\ce{O2^2-},$ the differentiating factor... |
Why does titanium have lower affinity than scandium? |
I have been given a problem to derive a relation for change in entropy from change in Gibbs free energy:
> Starting with the isothermal equation
>
> $$G(p_2) = G(p_1) + nRT\ln\frac{p_2}{p_1}\label{eqn:1}\tag{1}$$
>
> derive
>
> $$S(V_2) = S(V_1) + nR\ln\frac{V_2}{V_1}\label{eqn:2}\tag{2}$$
>
> using the rela... |
> Compare the acidic strength of *o*-, *m*-, *p*-aminobenzoic acids.
I got that *meta* will be the most acidic as it won't be able to show R+ effect of $\ce{NH2}.$
But among the other two, i.e. *ortho* and *para*, shouldn't *ortho* be more acidic as it will cause ortho effect?
But according to my book and the da... |
Why is para-aminobenzoic acid more acidic than ortho-aminobenzoic acid? |
Wouldn't C1 and C2 in phenylpropene be on the same plane as that of the phenyl ring, right? If the double bond connected to C2 was between it and C1, they would be, but is it correct that now they're both planar, but on different planes?
[![phenylpropene][1]][1]
[1]: https://i.stack.imgur.com/ZMxTW.png |
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