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From basic coordination chemistry and acid-base equilibria we understand that a metal hexa-aqua ion can be deprotonated until it's positive charge is balanced by the negative charge of the hydroxides rendering a neutral complex. We then say that this complex precipitates.
Recently in my inorganic class we studied h... |
Is hydrolytic polymerisation the mechanism by which the precipitate forms from the neutral complex? |
Why are the atomic and the mass numbers of an element flipped in the textbooks relative to the periodic table? |
This is actually really interesting question,
Glycine hydrochloride is salt of glycine amino acid. This means that HCl(hydrochlorid acid) has been used to protonate the molecule.
To understand better which part of the molecule is protonated we need to think about chemical structure of glycine and it's acidit... |
In the [periodic table](http://commons.wikimedia.org/w/index.php?title=Periodic_Table_of_Elements), the largest number is indeed the atomic number. This is the number of protons. Since this defines the element, it is considered the **most important** number.
What you probably mean is
$^A_Z\mathrm{Element\ symbol}$... |
In the [periodic table](http://commons.wikimedia.org/w/index.php?title=Periodic_Table_of_Elements), the largest number is indeed the atomic number. This is the number of protons. Since this defines the element, it is considered the **most important** number.
What you probably mean is
$^A_Z\mathrm{Element}$. Here, ... |
In the [periodic table](http://commons.wikimedia.org/w/index.php?title=Periodic_Table_of_Elements), the largest number is indeed the atomic number. This is the number of protons. Since this defines the element, it is considered the **most important** number.
What you probably mean is
$^A_Z\mathrm{Element}$. Here, ... |
**General Rule #1:** Most elements use only s and p orbitals to form bonds, only transition elements and heavier elements use d, f, *etc*. orbitals in bonding.
**General Rule #2:** The more s-character in a bond the shorter the bond ([reference][1]). For example
- a $\ce{C(sp^3)-C(sp^3)}$ single bond length is... |
The lewis structure of nitric acid is:
![enter image description here][1]
[1]: https://i.stack.imgur.com/zsRdd.png
So, since Pauling's rule is $pK_a=8-5p$, where p is the number of oxo groups, how is the rule applied in this instance? $p=1.5$? $p=2$? |
How are Pauling's rules applied to Nitric acid? |
why is pH of a buffer solution measured before measuring pH of unknown solutions ?
I do not have any idea about it . I had read chapter ionic equibillrium and electrochemistry but not able to find out answer. |
**General Rule #1:** Most elements use only s and p orbitals to form bonds, only transition elements and heavier elements use d, f, *etc*. orbitals in bonding.
**General Rule #2:** The more s-character in a bond the shorter the bond ([reference][1]). For example
- a $\ce{C(sp^3)-C(sp^3)}$ single bond length is... |
You have a beaker containing 542 mL of a solution of 0.48M acetate buffer (pKa = 4.76) at pH 4.2. To this solution, you add 342 mL of pure water. What is the pH of the resulting solution? The answer is 4.6. However, I do not know how to arrive at that answer. I know the H-H equation must be used (pH=pKa+log[A-]/[HA]) |
You have discovered a new strain of bacteria called Tankeromyces subtilis that has a special outer membrane that is capable of withstanding high levels of osmotic pressure. These bacteria can survive osmotic pressure as high 1.3 kJ/L, but not higher. The (ic)total value for the inside of these bacteria is 630 mM. What ... |
> You have a beaker containing 542 mL of a solution of 0.48M acetate buffer (pKa = 4.76) at pH 4.2. To this solution, you add 342 mL of pure water. What is the pH of the resulting solution?
The answer is 4.6. However, I do not know how to arrive at that answer. I know the H-H equation must be used (pH=pKa+log[A-]/[... |
> You have discovered a new strain of bacteria called Tankeromyces subtilis that has a special outer membrane that is capable of withstanding high levels of osmotic pressure. These bacteria can survive osmotic pressure as high 1.3 kJ/L, but not higher. The (ic)total value for the inside of these bacteria is 630 mM. Wha... |
I realize that the octet rule is more a suggestion than a rule, and that it applies mainly to non-transition metal compounds. Still, compounds that don't have an octet, like $\ce{BH3}$, tend to dimerize or disproportionate in order to achieve an octet.
In recent SE Chem posts relating to bonding in [phosphorous pe... |
I realize that the octet rule is more a suggestion than a rule, and that it applies mainly to non-transition metal compounds. Still, compounds that don't have an octet, like $\ce{BH3}$, tend to dimerize or disproportionate in order to achieve an octet.
In recent SE Chem posts discussing the bonding in [phosphorous... |
What is the relation between surface tension and initial molecular harmonic? |
Can acid mine drainage form acid rain?
Since normal acid rain is formed via combustion of fossil fuels, the sulphur dioxide and nitrogen dioxide are all in the gas phase, whereas in acid mines the sulphuric acid is in solution.
Here's the reaction if it helps.
![enter image description here][1]
[1]: ... |
Can acid mine drainage form acid rain? |
I don't think acid _rain_ formation from liquid acid mine drainage is very likely. The reason is that in acid rock drainage (a.k.a. acid mine drainage or AMD), the acidity is caused by sulfuric acid. Sulfuric acid, $\ce{H2SO4}$ is much less volatile than water. It simply won't appreciably evaporate from bulk liquids... |
Yes it's possible this way:
![enter image description here][1]
>Also, this raises another question - can't Grignards also create alkenes "by accident"?
It's very common. Grignard reagents will take away any acidic proton available. That's why we use Grignard reagents in anhydrous conditions, else it would take... |
Would 2,5-dinitropyrolle be a product of nitration of pyrolle with $\ce{H2SO4/HNO3}$ ? It seems from [this paper][1] that it is not formed using acetic anhydride/nitric acid - is this just because of the mild conditions used or does this reflect the pyrolle ring being more deactivated by nitro-substitution than a benze... |
![Question][1]
[1]: https://i.stack.imgur.com/1abW8.png
I have a question from a past exam that I'm using to revise.
I think the answer for part i/ii involves nucleophilic aromatic substitution with $\ce{NH2-}$ as the nucleophile. Part iii involves alkylation of the $\ce{N}$ followed by nucleophilic attac... |
> In $\ce{SO3}$, 2 $p\pi-d\pi$ bonds are present. But which $d$ orbitals of
> sulphur take part in these $\pi$ bonds?
The answer says $d_{xy}$ and $d_{yz}$. Someone also told me that crystal field theory supports it as while splitting $d_{x^2-y^2}$ and $d_{x^2}$ are raised in energy compared to the other 3, but tha... |
What are Isodiaphers? |
Would 2,5-dinitropyrrole be a product of nitration of pyrrole with $\ce{H2SO4/HNO3}$ ? It seems from [this paper][1] that it is not formed using acetic anhydride/nitric acid - is this just because of the mild conditions used or does this reflect the pyrrole ring being more deactivated by nitro-substitution than a benze... |
Are there any limits to rotating a compound in order to prove that its chirality or achirality? (assuming that you're rotating about a single bond) |
Can a meso compund be rotated in ANY sort of way in order to show its achirality? |
In [this][1] question, it is explained why salicylic acid is a stronger acid than benzoic acid. So, why acetylsalicylic acid (aspirin), whose conjugate base cannot hydrogen bond since there is no hydrogen, is still more acid than benzoic acid?
- aspirin: $\ce{pK_{a}}$ = 3.5
- benzoic acid: $\ce{pK_{a}}$ = 4.2
... |
Why is acetylsalicylic acid still more acid than benzoic acid? |
> Would 2,5-dinitropyrrole be a product of nitration of pyrrole with $\ce{H2SO4/HNO3}$?
I doubt it and would rather expect a lot of tar to be formed that a mixture for the nitration of pyrrole. Pyrrole tends to undergo acid-catalyzed polymerization!
For decades, acetyl nitrate, formed by addition of fuming nitric... |
Why is the pH of a buffer solution measured before measuring the pH of an unknown solution?
I do not have any idea about it. I had read a chapter about ionic equilibrium and electrochemistry, but have not been able to find out an answer. |
> Would 2,5-dinitropyrrole be a product of nitration of pyrrole with $\ce{H2SO4/HNO3}$?
I doubt it and would rather expect a lot of tar to be formed here. Pyrrole tends to undergo acid-catalyzed polymerization!
For decades, acetyl nitrate, formed by addition of fuming nitric acid to acetic anhydride, is the reage... |
In [this][1] question, it is explained why salicylic acid is a stronger acid than benzoic acid. So, why acetylsalicylic acid (aspirin), whose conjugate base cannot hydrogen bond since there is no hydrogen, is still more acid than benzoic acid?
- aspirin: $\mathrm{p}K_\text{a}$ = 3.5
- benzoic acid: $\mathrm{p}K_\... |
What is the graph of carbon dioxide ($\ce{CO2}$) content in the air in a compartment consisting of 80 percent air and 20 percent ocean sea water as a function of temperature, in the temperature range 0 to 60 degree Celsius?
Example but not the complete answer:
![enter image description here][1]
As can be seen ... |
> Would 2,5-dinitropyrrole be a product of nitration of pyrrole with $\ce{H2SO4/HNO3}$?
I doubt it and would rather expect a lot of tar to be formed here. Pyrrole tends to undergo acid-catalyzed polymerization!
For decades, acetyl nitrate, formed by addition of fuming nitric acid to acetic anhydride, is the reage... |
I don't think acid _rain_ formation from liquid acid mine drainage is very likely. The reason is that in acid rock drainage (a.k.a. acid mine drainage or AMD), the acidity is caused by sulfuric acid. Sulfuric acid, $\ce{H2SO4}$ is much less volatile than water. It simply won't appreciably evaporate from bulk liquids... |
> Is it possible for 'n' to ever be negative? Trying to figure out where I went wrong on some thing and want to rule that out.
The $\Delta G$ is the driving force and hence should be equal to external force under consideration for a reaction to be at equilibrium, hence we need to find that external force.
I know ... |
> Is it possible for 'n' to ever be negative? Trying to figure out where I went wrong on some thing and want to rule that out.
The $\Delta G$ is the maximum non expansion work and hence should be equal to external force under consideration times the distance for a reaction to be at equilibrium, hence we need to find... |
Is it possible to synthesize ester from an ether directly (only one step)? For example if I had an ether (R-CH2-OR') and oxidize it so it will be an ester (R-CO-OR'). |
Is it possible to oxidize ether to ester? |
> Is it possible for 'n' to ever be negative? Trying to figure out where I went wrong on some thing and want to rule that out.
The $\Delta G$ is the maximum non expansion work and hence should be equal to external force under consideration times the distance for a reaction to be at equilibrium, hence we need to find... |
> I am trying to understand the link between the two chemical bonds. Are they dependent on each other (e.g. one causes the other?)
One does not "cause" the other. Instead, the author is only trying to say that removing the 2' hydroxyl group from nucleotides does two things: (a) vastly _increases_ stability of 3' bo... |
> Is it possible for 'n' to ever be negative? Trying to figure out where I went wrong on some thing and want to rule that out.
$\Delta G$ is the maximum non expansion work and hence should be equal to external force under consideration times the distance for a reaction to be at equilibrium, hence we need to find tha... |
My professor sent out a review guide. One of the questions on this guide is "the carboxylic acid carbonyl oxygen is..." and the answer choices are
A) sp2
B) sp3
C) h bond donor
D) rapidly equilibrating between sp3 and sp2
E) a+c
F) a+d
I chose D because of the resonance that can be drawn with a negative Oxyg... |
My professor sent out a review guide. One of the questions on this guide is
> The carboxylic acid carbonyl oxygen is...<br/>
A) $sp^2$<br/>
B) $sp^3$<br/>
C) H bond donor<br/>
D) rapidly equilibrating between $sp^3$ and $sp^2$<br/>
E) a+c<br/>
F) a+d
I chose D because of the resonance that can be drawn with ... |
1. Calculate your **DBEs** (double bond equivalents):
\\[\mathrm{DBE} = \frac{2c-h+2}{2} = \frac{2\cdot 11 - 14 +2}{2} = 5\\]
Note that a benzene has 4 **DBEs**!
2. Shifts at 7.5 ands 7.4 are definitely not alkine protons. Aromatic protons are more likely, aren't they?
3. Largest couplings between benz... |
1. Calculate your **DBEs** (double bond equivalents):
\\[\mathrm{DBE} = \frac{2c-h+2}{2} = \frac{2\cdot 11 - 14 +2}{2} = 5\\]
Note that a benzene has 4 **DBEs**!
2. Shifts at 7.5 ands 7.4 are definitely not alkine protons. Aromatic protons are more likely, aren't they?
3. Largest couplings between benz... |
I broke a CFL in my home (so elemental mercury is present in a small amount) and wiped up some of the mess with a clorox wipe.
The wipe in question contains dimethyl benzyl ammonium chloride and dimethyl ethylbenzyl ammonium chloride.
I'm not chemical-phobic, but can someone please tell me, I didn't accidentally ex... |
Is it possible to synthesize ester from an ether directly (only one step)? For example if I had an ether $\ce{(R-CH2-OR')}$ and oxidize it so it will be an ester $\ce{(R-CO-OR')}$. |
$m_\text{e}=9.1\times10^{-31}\ \mathrm{kg}$, $T=2\times10^{6}\ \mathrm{K}$ and $p=0.030\ \mathrm{Pa}$ the solution is given as: $5.4\times10^6\ \mathrm{ms^{-1}}$ but I got $9.5\times10^6\ \mathrm{ms^{-1}}$ using the following method (which does not use the value given for pressure. I simply plugged the numbers into the... |
I've stumbled across a few problems that I need help on, it is mostly **Electrochemistry** and I will show my work.
> 1. **Redox Equation Balancing**: $$\ce{S8 + O2 + H2O -> H+ + SO4^{2-}}$$
At first when I saw this I didn't know what was going on, **Sulfur was being oxidized** and **Oxygen was being reduced**. ... |
I've stumbled across a few problems that I need help on, it is mostly **Electrochemistry** and I will show my work.
> 1. **Redox Equation Balancing**: $$\ce{S8 + O2 + H2O -> H+ + SO4^{2-}}$$
At first when I saw this I didn't know what was going on, **Sulfur was being oxidized** and **Oxygen was being reduced**. ... |
I've stumbled across a few problems that I need help on, it is mostly **Electrochemistry** and I will show my work.
> 1. **Redox Equation Balancing**: $$\ce{S8 + O2 + H2O -> H+ + SO4^{2-}}$$
At first when I saw this I didn't know what was going on, **Sulfur was being oxidized** and **Oxygen was being reduced**. ... |
I've stumbled across a few problems that I need help on, it is mostly **Electrochemistry** and I will show my work.
> 1. **Redox Equation Balancing**: $$\ce{S8 + O2 + H2O -> H+ + SO4^{2-}}$$
At first when I saw this I didn't know what was going on, **Sulfur was being oxidized** and **Oxygen was being reduced**. ... |
I've stumbled across a few problems that I need help on, it is mostly **Electrochemistry** and I will show my work.
> 1. **Redox Equation Balancing**: $$\ce{S8 + O2 + H2O -> H+ + SO4^{2-}}$$
At first when I saw this I didn't know what was going on, **Sulfur was being oxidized** and **Oxygen was being reduced**. ... |
Suppose we hold temperature, pressure, and gas composition (say, a standard atmosphere) constant. Then we know that if we allow the water content of the air to vary it can range between 0 and some saturation limit _S_ g/L.
How does that saturation limit vary with the composition of the air? For example, does it de... |
How does composition of air affect vapor saturation limit? |
I need to calculate the molar mass and density of the shape memory alloy Co49Ni21Ga30 (I suppose the numbers indicate the mass percentage).
For the molar mass, is it correct to use the formula below?
Mol_mass_compound = Mol_mass_Co*0.49 + Mol_mass_Ni*0.21 + Mol_mass_Ga*0.30
Regarding the density, how do ... |
How come diluting a cell decreases the voltage? |
I've stumbled across a few problems that I need help on, it is mostly **Electrochemistry** and I will show my work.
> 1. **Redox Equation Balancing**: $$\ce{S8 + O2 + H2O -> H+ + SO4^{2-}}$$
At first when I saw this I didn't know what was going on, **Sulfur was being oxidized** and **Oxygen was being reduced**. ... |
I'd like clarification of the meaning of $W_{max}$ in the following equations (and thus in the combined result in the third equation):
$W_{max} = \Delta G$
$W_{max} = -nF\varepsilon$
$\Delta G = -nF\varepsilon$
In the first equation, we somehow come to the conclusion that the maximum useful work available f... |
This might be a dumb question, but given that the half-lives differ between isotopes of a particular radioactive element, wouldn't the natural abundance change (fairly rapidly)?
For example, if we isolated a bunch of thorium, wouldn't the relative amount of the various isotopes of thorium in the sample differ over t... |
Change in natural abundance of radioactive elements? |
I am trying to learn to work with CP2K and now need to make its input file. CP2K has kind of [adaptor][1] for **Avogadro2** but not Avogadro ( I don't know what is the relation between them !). I also tried that adaptor plugin with Avogadro2 but it does not work for me ( tried on Mac OS X Yosemite and Windows 7).
I... |
How to make a CP2K input file with Avogadro? |
I'm interested in the mushroom cloud produced by a nuclear explosion: What is it made of?
![enter image description here][1]
I know that the uranium fission reaction is the following (from [this web page][2])
$$\ce{{}^{235}U + {}^1_0n -> {}^{95}Sr + {}^{139}Xe +2~{}^1_0n + 180~MeV}$$
I know that these eleme... |
What chemical elements does a nuclear explosion release into its mushroom cloud? |
About 2 years ago I purchased 2 liters of 98% concentrated sulfuric acid. It's in a standard poly bottle with leakproof lids, and originally was clear. Recently I noticed the acids have turned a dark gray; almost black color. They have both never been opened.
I suspect there was something in the lid that was eroded ... |
Why would sulfuric acid turn gray/black? |
I need to calculate the molar mass and density of the shape memory alloy $\ce{Co49Ni21Ga30}$
(I suppose the numbers indicate the mass percentage).
For the molar mass, is it correct to use the formula below?
Mol_mass_compound = Mol_mass_Co*0.49 + Mol_mass_Ni*0.21 + Mol_mass_Ga*0.30
Regarding the densi... |
If I mix water in a cup with sugar at some stage the solution will become saturated and no more sugar will dissolve into the water. If I now add salt to the solution will the salt dissolve into the water or is the solution already saturated? |
What would happen if I mix Salt and Sugar in a cup of water? |
Why something jelly forms in the water if it is kept in in a ultrasonication bath for long periods? |
How can we record a IR spectrum of a substance coated on a OHP sheet?
instrument has both transmission and ATR modes |
In nucleophilic aromatic substitutions, I was wondering how to reduce the acyl group down to get a chain of hydrocarbons, but still keep the nitro group intact without its reduction to an amino group. A Clemmensen reduction would reduce the Nitro group and it seems like other reducing agents will also reduce the nitro ... |
Did you consider to convert to the ketone to the corresponding tosylhydrazone and reduce that with $\ce{NaCNBH3}$? ([DOI](http://dx.doi.org/10.1021/jo00278a035)).
|
What is the basis set that can be used to study the interaction of H-atom with Pt-CNT dropcasted electrode? How can we study the energy differences that arises due to the interaction computationally? |
Why something jelly forms in the water if it is kept in in a ultrasonication bath for long periods?
When water is exposed to ultrasonication for say a month, some jelly substances form in the ultrasonicator bath. is this something related to some bioorganism growth? |
If I mix water in a cup with sugar at some stage the solution will become saturated and no more sugar will dissolve into the water. If I now add salt to the solution will the salt dissolve into the water or is the solution already saturated?
I have not tried an experiment as I cannot figure out how to measure the di... |
What would happen if I mix salt and sugar in a cup of water? |
I need to calculate the molar mass and density of the shape memory alloy $\ce{Co49Ni21Ga30}$
(I suppose the numbers indicate the mass percentage).
To get the molar mass, is it correct to use the formula below?
Mol_mass_compound = Mol_mass_Co*0.49 + Mol_mass_Ni*0.21 + Mol_mass_Ga*0.30
Regarding the de... |
How can we record a IR spectrum of a substance coated on a Over Head Projector (OHP) sheet?
instrument has both transmission and ATR modes |
Why is Lead (Pb) radioactive?
Radioactivity refers to release of alpha beta gamma rays.
What property of Lead makes it so? |
Why is lead radioactive? |
Before explaining why lead is radioactive? I would like to brefeily explain what is radioactivity?
According to wiki
> Radioactive decay, also known as nuclear decay or radioactivity, is
> the process by which a nucleus of an unstable atom loses energy by
> emitting ionizing radiation. A material that spontaneo... |
Before explaining why lead is radioactive? I would like to brefeily explain what is radioactivity?
[According to wikipedia][1]
> Radioactive decay, also known as nuclear decay or radioactivity, is
> the process by which a nucleus of an unstable atom loses energy by
> emitting ionizing radiation. A material that... |
I'd like clarification of the meaning of $W_\mathrm{max}$ in the following equations (and thus in the combined result in the third equation):
\begin{align}
W_\mathrm{max} &= \Delta G\\
W_\mathrm{max} &= -nF\varepsilon\\
\Delta G &= -nF\varepsilon\\
\end{align}
In the first equation, we somehow come to the concl... |
What is the precise definition of Wₘₐₓ in the context of electrochemistry and thermodynamics? |
In a paper I am reading regarding instability and decay of DNA, the author says:
"The chemical price paid for the greatly increased resistance of the nucleic acid phosphodiester bond (gained by removal of the sugar 2'-OH group) is the labile N-glycosyl bond"
I am trying to understand the link between the two che... |
Before explaining why lead is radioactive? I would like to briefly explain what radioactivity is.
[According to wikipedia][1]:
> Radioactive decay, also known as nuclear decay or radioactivity, is
the process by which a nucleus of an unstable atom loses energy by
emitting ionizing radiation. A material that s... |
What is the basis set that can be used to study the interaction of $\ce{H}$-atom with $\ce{Pt-CNT}$ dropcasted electrode? How can we study the energy differences that arises due to the interaction computationally? |
How can we record a IR spectrum of a substance coated on a Over Head Projector (OHP) sheet?
instrument has both transmission and ATR modes. IR spectrum is to be recorded for both the OHP sheet as well as the material that is coated on it
|
What is the basis set in the computational software "Gaussian-03" that can be used to study the interaction of $\ce{H}$-atom with $\ce{Pt-CNT}$ dropcasted electrode? How can we study the energy differences that arises due to the interaction computationally? |
What does the Mesh in the mesh size of silica gel that is used for various chromatography techniques mean? |
Hi I was wondering why when acetaldehyde is treated with OH-, the OH- will attack the methyl group instead of the carbonyl carbon, forming an enolate anion. I would have though that the OH- would have attacked the carbonyl carbon due to it having a relative positive charge...
Additionally, my professor said during ... |
I've stumbled across a problem that I need help on, it is mostly **Electrochemistry** and I will show my work.
> 1. **Line Notation Error**: $$\ce{Fe~|~Fe^{+2}~||~Cl^{-},Cl2~|~Pt}$$
After that, I understood that **Iron** is at the anode and is being oxidized, however I do not know what was going on with **Chlori... |
Hi I was wondering why when acetaldehyde is treated with $\ce{OH-}$, the $\ce{OH-}$ will attack the methyl group instead of the carbonyl carbon, forming an enolate anion. I would have though that the $\ce{OH-}$ would have attacked the carbonyl carbon due to it having a relative positive charge.
Additionally, my pro... |
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