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Why water vapors exerts pressure rather than diffusing in air before reaching the boiling point of water? |
I've been trying to find out as much as I can about peracetic acid, especially regarding its use as a sanitizer. In the [Wikipedia entry](http://en.wikipedia.org/wiki/Peracetic_acid#Production) it notes that
>*"[p]eracetic acid is always sold in solution with acetic acid and hydrogen peroxide to maintain the stabil... |
> Do epoxied rings react with bases
Yes, they can be opened, e.g. with alkoxides.
> what is the mechanism?
![enter image description here][1]
In principle, this is a $S_N2$ reaction, with the typical approach of the nucleophile from the back side. The difference to a non-epoxide case is that removal of the ... |
The formation of peracetic acid from acetic acid and hydrogen peroxide is an equilibrium reaction and so in order for the peracetic acid to remain at a constant concentration as desired, acetic acid and hydrogen peroxide must also be present so that the reaction can be at equilibrium. $$\ce{CH3COOH + H2O2 <=> CH3COOOH ... |
The formation of peracetic acid from acetic acid and hydrogen peroxide is an equilibrium reaction and so in order for the peracetic acid to remain at a constant concentration as desired, acetic acid and hydrogen peroxide must also be present so that the reaction can be at equilibrium. $$\ce{CH3COOH + H2O2 <=> CH3COOOH ... |
How can I store distilled water without introducing impurities? I'm going to be doing so electrical studies of pure water and ice and I need a way of keeping the water pure during the experiments. The water needs to remain relatively pure (I'm not yet entirely sure how relative yet), over at least the course of $1$ d... |
What is the role of POCl₃ in this reaction? |
Why does K⁺ have 0 valence electrons? |
Why can't an enolate anion successfully displace a halogen from a benzene? I am told that the geometry is incorrect; that such SN2 substitutions take place on $\mathrm{sp^3}$ hybridized (i.e. tetrahedral) substrates.
This reasoning is circular. So what's a better reason?
I can think of one reason but it is not ... |
When attacking a benzene ring for an SN2 reaction, I think your explanation is good enough. The $\ce{C-X}$ antibonding orbital lies in the plane and inside the ring. The nucleophile would be forced to approach through the rest of the atoms of the ring.
As for other $\mathrm{sp^2}$ hybridized organohalides, there was... |
> Why can't an enolate anion successfully displace a halogen from a benzene?
As you know enolate is the conjugate base of enol which is a tautomeric form of ketone. Thus being an electron rich molecule it basically acts like a nucleophile.
![enter image description here][1]
Aryl halides are extremely less re... |
Does C₂H₅OH react with K to form C₂H₅OK and H₂? |
I did a reaction to form $\ce{(NPCl2)3}$
The reagents I used were:
Phosphorus Pentachloride $\ce{PCl5}$
ammonium chloride $\ce{NH4Cl}$
Chlorobenzene - the solvent
Phosphorus oxychloride $\ce{POCl3}$
The reaction is $\ce{3 PCl5 + 3 NH4Cl -> (NPCl2)3 + 12HCl}$
Where the chlorobenzene is the solvent.... |
Is it possible to make a drug that liquefies heart plaque to treat heart disease without damaging other parts of the body? If so, would the liquefied plaque be eliminated as regular fluid is through the kidneys? I believe that if this is possible, it would definitely be worthwhile to make as it could save many lives! |
Is it possible to make a drug that liquefies heart plaque to treat heart disease? |
I asked my chemistry teacher this today and didn't get an answer. It would seem to me that the equation for determining the morality of the unknown in a titration, MaVa = MbVb, would only work if the acid and the base were both strong.
I always interpreted the equation as a way to say (moles H+)=(moles OH-), but if ... |
Why is Ma*Va=Mb*Vb still valid for weak acids/bases? |
I have a very very general question:
In DFT functional selection , mostly people speak about the most recent ones. For example my professor always asks: " which DFT Functional did you select ? " and if I say B3LYP, he says : " No ! that's too old ! " but if I answer: M06 , he says : " hmm ... sounds promising, tha... |
What does this property of transition metals mean? |
Does an acetal give a positive Tollens test? |
I Do not understand why and how an atom with sp2 hybridization has only one p orbital??
For example in pyridine why is the lone pair of nitrogen not counted as a pi electron. |
What is the amount of energy needed to boil one litre of tap-water in a regular kettle starting at room temperature?
The calculation itself assuming ideal and standard prerequisites would be interesting as well as factoring in the non-purity of tap-water and a typical kettle performance factor. |
What is the amount of energy (J or Wh) needed to boil one litre of tap-water in a regular kettle starting at room temperature?
The calculation itself assuming ideal and standard prerequisites would be interesting as well as factoring in the non-purity of tap-water and a typical kettle performance factor. |
I fail to understand why the hybridization of oxygen in furan is sp2. I think that since there are 2 bond pairs and two lone pairs so it should be sp3 hybridized?
Is it to do with the aromaticity of furan?
Please help |
Hybridization of the oxygen in furan? |
I fail to understand why the hybridization of oxygen in furan is $\ce{sp^2}$. I think that since there are 2 bond pairs and two lone pairs so it should be $\ce{sp^3}$ hybridized?
Is it to do with the aromaticity of furan?
Please help |
I do not understand why and how an atom with $\ce{sp^2}$ hybridization has only one p orbital??
For example in pyridine why is the lone pair of nitrogen not counted as a pi electron. |
I've been in a few classes now that teach about energy, and I feel they're always so bad. There is always such a rush to start using equations to get problems solved, and I often feel I don't have an intuitive grasp on energy at all. I guess this question is also about pressure.
Questions:
1. Does pressure decre... |
the question is,
The two squareplanar isomers of ptbrclpr32 have a different p-nmr spectra. One shows single group of lines, the other shows two distinct resonances, each one being similar to the single resonance region of the first one. Which isomer is cis and which is trans?
Thanks.. |
Chemical shifts and multiplicity are always controlled by:
**Who sees what?**
If two centres have the same environment/neighbours or are related by a symmetry operation, they will have identical shifts.
Here, the phosphor atoms in the *trans* isomer both "see" the same and appear as a single set of lines. |
the question is,<br>
The two squareplanar isomers of $\ce{PtBrCl(PR3)2}$ have a different p-nmr spectra. One shows single group of lines, the other shows two distinct resonances, each one being similar to the single resonance region of the first one. Which isomer is cis and which is trans?
Thanks. |
Which is cis and which is trans? |
the question is,<br>
The two square planar isomers of $\ce{Pt[BrCl(PR_{3})2]}$ have a different $\ce{^{31}P}$-nmr spectra. One shows single group of lines, the other shows two distinct resonances, each one being similar to the single resonance region of the first one. Which isomer is cis and which is trans?
Thanks. |
Pt[BrCl(PR₃)₂] cis, trans isomer nmr - Which is cis and which is trans? |
Non-halogen intermediate between alkane and alcohol under basic conditions? |
> 1.Does pressure decrease with time?
The ideal gas law tells us that
$$PV=nRT$$
or
$$\ce{P=\frac[nRT][V]}$$
If the temperature, number of moles or volume does not change, then the pressure will not change.
> If pressure is caused by the force of gas molecules hitting the inside
> surface of a container... |
There are many criteria that you can follow to choose a functional, in no special order:
a) Availability: Do you have access to a software package in which the functional is implemented? If yes, are analytic derivatives also implemented? Do you need extra dispersion corrections? Are they available?
b) Computation... |
What is an orbital boundary surface? |
There are many criteria that you can follow to choose a functional, in no special order:
a) Availability: Do you have access to a software package in which the functional is implemented? If yes, are analytic derivatives also implemented? Do you need extra dispersion corrections? Are they available?
b) Computation... |
The binding of oxygen by haemoglobin giving oxy-haemoglobin is partially regulated by the concentration of H3O+ and dissolved in CO2 in blood
$${HbO2+H3O++CO2<=>H+.Hb.CO2 +O2+H2O}$$
If there is production of lactic acid and $CO2$ in a muscle during excretion then is more oxygen released or is more $HbO2$ formed? |
What is the amount of energy (J or Wh) needed to boil one litre of tap-water in a regular kettle starting at room temperature (20°C)?
The calculation itself assuming ideal and standard prerequisites would be interesting as well as factoring in the non-purity of tap-water and a typical kettle performance factor. |
The binding of oxygen by haemoglobin giving oxy-haemoglobin is partially regulated by the concentration of $\ce{H3O+}$ and dissolved in $\ce{CO2}$ in blood
$$\ce{HbO2 + H3O+ +CO2<=>H+.Hb.CO2 + O2 + H2O}$$
If there is production of lactic acid and $\ce{CO2}$ in a muscle during excretion then is more oxygen released o... |
My chemistry text book says that "Atomic Absorption Spectrometry (AAS) can be used to determine the concentration of metal ions, but other methods must be used for anions. One convenient method is to use an ion-selective electrode (ISE)." What is the reason? Why can't ASP be used for determining the concentration of an... |
Why is Lanthanum a "fluoride ion sensitive electrode" and hence used for measuring "flouride concentration"? |
The formation of peracetic acid from acetic acid and hydrogen peroxide is an equilibrium reaction and so in order for the peracetic acid to remain at a constant concentration as desired, acetic acid and hydrogen peroxide must also be present so that the reaction can be at equilibrium. $$\ce{CH3COOH + H2O2 <=> CH3COOOH ... |
>Does pressure decrease with time? If pressure is caused by the force of gas molecules hitting the inside surface of a container, don't they transfer energy and eventually slow down enough to totally reduce pressure?
No. As you know, an aerosol can remains pressurised indefinitely until it is used. The molecules do ... |
In one problem it's asking me to find the solubility of Ca(OH)2 in water. In that problem it assumes the starting concentration OH to be zero. But for other problems like BaSO4 in 0.1M Na2SO4, we account for the SO4 in the NaSO4. So in the first problem, why don't we worry about the OH from the self ionization of water... |
In one problem it's asking me to find the solubility of $\ce{Ca(OH)2}$ in water. In that problem it assumes the starting concentration $\ce{OH}$ to be zero. But for other problems like $\ce{BaSO4}$ in $0.1~M~~ \ce{Na2SO4}$, we account for the $\ce{SO4}$ in the $\ce{NaSO4}$. So in the first problem, why don't we worry a... |
![enter image description here][1]
Graphs such as the above keep coming up when talking about harmonic oscillators in a quantum mechanical sense. However, I simply cannot make sense of them. What does each line represent why are they waves and what is the parabola? Also, I see sometimes graphs such as:![enter imag... |
As is well known, water can be electrolyzed into oxygen and hydrogen gasses. However, all redox reactions can be run in reverse. If I were to electrolyze water in 2 closed containers (in order to trap the gasses) and i were to run the cell in reverse using a battery, would the hydrogen and oxygen gasses turn back into ... |
Ionize Hydrogen and Oxygen Gas in Electrolytic Cell? |
**Background**
Let's start by considering the case of 2 hydrogen atoms separated by a large distance. If they happen to be on a trajectory that brings them closer together they can interact with one another. If they get close enough together they can form a bond and create a hydrogen molecule. This process is pic... |
**Background**
Let's start by considering the case of 2 hydrogen atoms separated by a large distance. If they happen to be on a trajectory that brings them closer together they can interact with one another. If they get close enough together they can form a bond and create a hydrogen molecule. This process is pic... |
If I determine the order of the reactants in a reaction without using a catalyst, and then use a catalyst, will the order of the reactants then be different? |
For the process, CH3OH(l) --> CH3OH(g)
∆G° = 4.30 kJ/mol at 25 °C. What is the vapor pressure
of CH3OH(l) at 25 °C in mm Hg?
A) 0.176 mm Hg (B) 14.0 mm Hg
(C) 134 mm Hg (D) 759 mm Hg
This question is from the 2012 National Chemistry Olympiad (US).
Attempt at solution:
∆G° = -RTlnK
4.3x10^3 J/mol= -8.314 J... |
**Background**
Let's start by considering the case of 2 hydrogen atoms separated by a large distance. If they happen to be on a trajectory that brings them closer together they can interact with one another. If they get close enough together they can form a bond and create a hydrogen molecule. This process is pic... |
Other isomers include 1-butene, cis 2-butene, and trans 2-butene. Why would 2-methylpropene be less in energy if there is more steric hindrance? |
Why is 2-methylpropene less in energy than its alkene counterparts? |
How to find molecular charge in simulation softwares like Avogadro? |
$\ce{[NEt4]2[NiBr4]}$ dissolved in $\ce{MeCN}$ and $\ce{[NEt4]2[NiBr4]}$ dissolved in $\ce{H2O}$ have different UV/visible spectra in the visible region. How would they differ, for example would one of them have more peaks? Also how would the molar extinciton coefficients differ and what do these numbers tell you? |
we were taught that nitric acid can oxidize cl- to cl2, but sulphuric can't. Is this due to it's smaller size, or structure, or what? |
why is nitric a stronger oxidising agent than sulphuric? |
Hno3 always reduces its anion to give n=containing compounds 9 no2, no, and even n2o when reacting with metals, but with mg and mn it releases h2. Is there a specific reason for this variation? |
why does nitric acid release hydrogen ONLY when reacting with Mg and Mn? |
I have a confusion... Do compounds like tropolone, furan and thiophene which are aromatic show resonance?
If yes then what are the resonating structures ?
Also do all aromatic compounds show resonance ?? |
Why is p-Methoxyphenol more acidic than p-Methylphenol?
According to me, inductive effect really doesn't matter at para positions and p-Methoxyphenol should be less acidic due to the high mesomeric effect of the $-OCH_3$ group in comparison to the weak hyperconjugative effect of the $-CH_3$ group.
[p-Methoxypheno... |
When chloral undergoes reaction with a concentrated alkali, will it undergo cannizarro reaction to form the corresponding alcohol and acidic salt, or should it form chloroform instead by departure of trichloro carbanion instead of the hydride ion?
I understand that the trichlorocarbanion is stabilized by the $-H$ e... |
Spectrum of CO2 at 2349cm^-1 region
For some other molecules (for example CO) the peak separation corresponds to 2B (where B is the rotational constant wavenumber)
However for CO2 when I calculated the peak s... |
What does the peak separation of carbon dioxide IR rotational-vibrational spectrum corresponds to and why? |
All google searches have simply returned more info on catalase. I'm looking for a catalyst that isn't found inside living organisms which can break down H2O2. Looking for any resources to look at, or just examples of other catalysts.
Side question since I don't want to clutter with a new thread. Can catalase be used... |
Spectrum of CO2 at $2349\space \mathrm{cm^{-1}}$ region
For some other molecules (for example CO) the peak separation corresponds to 2B (where B is the rotational constant wavenumber)
However for CO2 when ... |
All Google searches have simply returned more info on catalase. I'm looking for a catalyst that isn't found inside living organisms which can break down $\ce{H2O2}$. Looking for any resources to look at, or just examples of other catalysts.
Side question since I don't want to clutter with a new thread. Can catalase ... |
Spectrum of $\ce{CO2}$ at $2349\space \mathrm{cm^{-1}}$ region
For some other molecules (for example $\ce{CO}$) the peak separation corresponds to $2B$ (where $B$ is the rotational constant wavenumber)
How... |
In the [Cannizarro reaction][1] an aldehyde with **no alpha-hydrogens** is treated with $\ce{OH^-}$. Through a series of equilibria the aldehyde goes on to disproportionate into the corresponding carboxylate and alcohol as shown in the following mechanism.
![enter image description here][2]
Again, the only requi... |
Why do E2 reactions(dehydrohalogenation) only occur when the hydrogen and leaving group are in the same plane? |
In the [Cannizarro reaction][1] an aldehyde with **no alpha-hydrogens** is treated with $\ce{OH^-}$. Through a series of equilibria the aldehyde goes on to disproportionate into the corresponding carboxylate and alcohol as shown in the following mechanism.
![enter image description here][2]
Again, the only requi... |
On regular paper, ink is absorbed, while on photopaper ink stays at the surface and dries for a longer time. What forces act in these two different cases?
(related question: http://chemistry.stackexchange.com/questions/24007/how-are-pencil-marks-adhered-to-the-paper) |
What forces hold ink on paper? |
On regular paper, ink is absorbed, while on photopaper ink stays at the surface and dries for a longer time. What forces act in these two different cases?
(related questions: http://chemistry.stackexchange.com/questions/24007/how-are-pencil-marks-adhered-to-the-paper, http://chemistry.stackexchange.com/questions/243... |
According to Wikipedia what gives epoxy it's holding power is apparently "ionic" interactions between the epoxy and the surface.
But I thought that epoxy was overall neutral when cured. How can it make ionic bonds with the surface it is bonded to? Or are there unprotonated alkoxides left in the epoxy which then mak... |
How does epoxy stick to stuff? |
On regular paper, ink is absorbed, while on photopaper ink stays at the surface and dries for a longer time. What forces act in these two different cases?
(see also related questions about [pencil marks](http://chemistry.stackexchange.com/questions/24007/how-are-pencil-marks-adhered-to-the-paper) and [colorants](htt... |
2s orbitals are stabilized more than 2p orbitals by the effective nuclear charge because of better penetration.
Everything you wrote above is correct **excep**t for,
> 2p orbitals are more stabilized because they penetrate less in the
> space of the 1s orbital
It is correct that they penetrate less, but they... |
I have a buffer containing 0.2000 M of the acid HA, and 0.1500 M of it's conjugate base A-, with a pH of 3.35. I need to find the pH after 0.0015 mol of NaOH is added to 0.5000 L of the solution.
I started by converting everything to moles, writing out an equation for HA and OH reacting to make H2O and A-, getting 0... |
Can neutralization be reversed? |
I have a buffer containing 0.2000 M of the acid HA, and 0.1500 M of it's conjugate base A-, with a pH of 3.35. I need to find the pH after 0.0015 mol of NaOH is added to 0.5000 L of the solution.
I started by converting everything to moles, writing out an equation for HA and OH reacting to make H2O and A-, getting 0... |
**Background**
On the topic of identifying an organic compounds using peaks generated in *Mass Spectrometry*, a rule of thumb expressed in the UK educational textbook, CGP, is that that "the M peak is the one with the second highest mass/charge ratio".
**Question**
What is the significance of this M peak anywa... |
What is the significance of an organic compound's M peak? |
Question 7 of Edexcel's June 2014 Unit 2 exam paper reads:
> In a mass spectrum of butane, C4H10, where would a peak be seen for
> the molecular ion if it had a charge of 2+?
The answer is 29.
My question is: why?
|
Why would the 2+ molecular ion of butane have a mass spectrum peak at 29? |
E2 reactions ([dehydrohalogenation][1]) only occur when the hydrogen and leaving group are in the same plane.
I can't think of a reason that they would need to be in the same plane, so what is the reason for this strange phenomenon?
[1]: https://en.wikipedia.org/wiki/Dehydrohalogenation
|
Why do E2 reactions (dehydrohalogenation) only occur when the hydrogen and leaving group are in the same plane? |
**Background research**
- Magnesium hydroxide exists naturally as Brucite ([source: wiki][1])
- Passing hot steam over magnesium produces magnesium oxide (source: [Edexcel's June 2014 Unit 2 exam (CH02_01): question 18][2])
**Question**
Why doesn't magnesium hydroxide form when treated with hot steam, inste... |
Why does hot steam produce MgO instead of MgOH? |
How to find molecular charge of fragments using quantum calculations? |
Your question boils down to "where are the electrons" in a quantum chemical system?
The problem, is if there's any level of interaction between the two fragments, **you don't know**. The charge will be delocalized across the entire A+B complex.
Put it another way.. Let's say you have a bunch of atoms and you run ... |
I bought a thermometer from Cole-Parmer having kerosene as the fluid, and the fluid is broken up. The fluid in the bottom part goes up to about 10C even though it is 20C in the room, then there is a gap followed by fluid between 23C and 25C, then there is no fluid going all the way to the top where there is another sma... |
Thermometer fluid is separated, defective? |
There are many criteria that you can follow to choose a functional, in no special order:
- Availability: Do you have access to a software package in which the functional is implemented? If yes, are analytic derivatives also implemented? Do you need extra dispersion corrections? Are they available?
- Computational... |
There are many criteria that you can follow to choose a functional, in no special order:
- Availability: Do you have access to a software package in which the functional is implemented? If yes, are analytic derivatives also implemented? Do you need extra dispersion corrections? Are they available?
- Computational... |
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