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There's actually two questions being asked here:
>What is holding ink on paper?
and
> Why do some inks take longer to dry?
Ink sticks to paper because it has a high affinity for the medium it's being applied to. To group things into simple categories we could say, there are hydrophobic inks (non-polar inks ... |
The question is as in the title.
I know that for a one-component hard-sphere gas, there is an analytic solution in the $\vec{k}$-space (PRA, 5, 939). I know that to obtain the correct solution in $r$-space I just need to do something like a Fast Fourier Transform. The problem is that in doing so I can only obtain v... |
Radial Distribution Function for a One-component Hard Sphere Gas - Is There a Quick Way to Evaluate it Numerically, at Arbitrary $r$? |
Radial Distribution Function for a Hard Sphere Gas in the Percus-Yevick Approximation - Is There a Quick Way to Evaluate it Numerically? |
Normal metals like sodium or Calcium have a positive charge as $\ce{Na}^+$ or $\ce{Ca}^{2+}$.
Transition metals have a loot of variable oxidation states.
>Yesterday i read about Iridium in Wikipedia and it stated that a **+9** oxidation state has been found in $\ce{IrO_4^+}$ which is astounding for me...
So i ... |
elements of group 6A, compared to 5A, requires less ionization energy due to the paired electrons of 6A
but a question arises... why group 7A,compared to group 6A, requires more ionization energy in spite of the paired electrons in group 7a,too.
regardless of the GENERAL trend that the ionization energy increases... |
How adding one more electron increases the ionization energy? |
I'm trying to find a substitute of Glucono delta-lactone (GDL). This food additive is usually used to produce silk tofu. Because of its slow hydrolysis the pH decreases very smoothly, which results in a tofu(coagulated soy milk protein) very soft. At the same time it is neutral in flavour, which is a great feature for ... |
I am trying to determine the concentration of products from the kinetic reactions of wood pyrolysis. The kinetic scheme separates the wood into cellulose, hemicellulose, and lignin. For example, the kinetic reactions for just the cellulose are shown below:
![kinetic reactions][1]
The $G1$ and $G2$ terms represent... |
#What's up with all that magic? (A chapter formerly known as Introduction)
The hunt for for the holy grail of density functional theory (DFT) has come a long way.<sup>\[1\]</sup> Becke states in the introduction of the cited paper:
> Density-functional theory (DFT) is a subtle, seductive, provocative business. Its ... |
Normal metals like sodium or Calcium have a positive charge as $\ce{Na}^+$ or $\ce{Ca}^{2+}$.
Transition metals have a loot of variable oxidation states.
Yesterday I read about Iridium in Wikipedia and it stated that
>a **+9** oxidation state has been found in $\ce{IrO_4^+}$
which is astounding for me...
So ... |
Most of the first electron affinities are positive, therefore the second ones are negative, and vice versa.
but why?
SPECIALLY WHEN THE FIRST ELECTRON AFFINITY IS NEGATIVE .. WHY THE SECOND ONE IS POSITIVE? |
Why does the second electron affinity has an opposite sign of the first one? |
There have been various explanations posited for the [$\alpha$-effect](http://en.wikipedia.org/wiki/Alpha_effect). The $\alpha$-effect refers to a phenomenon wherein nucleophiles with lone pairs on atoms adjacent (i.e., in the $\alpha$- position) to the atom bearing the reacting lone pair sometimes exhibit dramatically... |
I am trying to determine the concentration of products from the kinetic reactions of wood pyrolysis. The kinetic scheme separates the wood into cellulose, hemicellulose, and lignin. For example, the kinetic reactions for just the cellulose are shown below:
![kinetic reactions][1]
The $G1$ and $G2$ terms represent... |
I'm trying to find a substitute of Glucono delta-lactone (GDL). This food additive is usually used to produce silk tofu. Because of its slow hydrolysis the pH decreases very smoothly, which results in a tofu(coagulated soy milk protein) very soft. At the same time it is neutral in flavour, which is a great feature for ... |
Where can you find the enthalpy and gibbs free energy of formation and entropy of compounds either as a data file or web api (I technically only need two since I can figure out the other one from two of them)? |
Not sure what kind of explanation you are looking for, but
[Electrode Dynamics, A. C. Fisher, Oxford Chemistry Press, 1996, ISBN: 019855690X](https://global.oup.com/academic/product/electrode-dynamics-9780198556909?cc=us&lang=en&)
is a great concise explanation of overpotentials among other things. |
NIST is the best place to turn for lots of data. However, more easily parsed, smaller datasets are available in a couple of other locations.
1. The [`CHNOSz` package](http://www.chnosz.net/) in `R` has thermochemical data for a variety of species, mostly inorganic. Their database is referenced back to the chemical... |
There's actually two questions being asked here:
>What is holding ink on paper?
and
> Why do some inks take longer to dry?
Ink sticks to paper because it has a high affinity for the medium it's being applied to. To group things into simple categories we could say, there are hydrophobic inks (non-polar inks ... |
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... |
One question in a test I am preparing for is "What is the ratio of copper(II) ions to EDTA in a $[Cu(EDTA)]^{2-}$ complex?". I know that EDTA forms up to 6 coordinate bonds with the central atom, but is that what they are asking for with "ratio"? |
"From the reaction of NiBr2 and Ph2EtP, it is possible to isolate green and red crystals of [Ni(Ph2EtP)2Br2].
A) coordination number and geometries of the complexes?
B) possible isomeric structures for the green and red crystals."
I know that d orbitals effect the color but I don't know how to apply it to isomers... |
One question in a test I am preparing for is "What is the ratio of copper(II) ions to EDTA in a $[Cu(EDTA)]^{2-}$ complex?". I know that EDTA forms up to 6 coordinate bonds with the central atom, but is that what they are asking for with "ratio"?
According to [this website](http://www.chemthes.com/entity_datapage.php?... |
One question in a test I am preparing for is:
>What is the ratio of copper(II) ions to EDTA in a $\ce{[Cu(EDTA)]^{2-}}$ complex?
I know that EDTA forms up to 6 coordinate bonds with the central atom, but is that what they are asking for with "ratio"?
According to [this website](http://www.chemthes.com/entity_data... |
Ratio of copper(II) ions to EDTA? |
In my next lab, I'll be doing a complexometric titration of a copper solution with EDTA and a murexide indicator. The lab guide advises to keep the pH level nearly neutral by adding a diluted $NH_3$ solution. Why is that necessary?
I understand that during the formation of the copper complex $[Cu(EDTA)]^{2-}$, the s... |
Why should a complexometric titration be kept neutral? |
>"From the reaction of $\ce{NiBr2}$ and $\ce{Ph2EtP}$, it is possible to isolate green and red crystals of $\ce{[Ni(Ph2EtP)2Br2]}$?<br/>
A) coordination number and geometries of the complexes?<br/>
B) possible isomeric structures for the green and red crystals."
I know that d orbitals effect the color but I don't ... |
In my next lab, I'll be doing a complexometric titration of a copper solution with EDTA and a murexide indicator. The lab guide advises to keep the pH level nearly neutral by adding a diluted $\ce{NH3}$ solution. Why is that necessary?
I understand that during the formation of the copper complex $\ce{[Cu(EDTA)]^{2-}... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/2nx1N.png
I am struggling to find a mechanism for the above reaction. So far I have suggested that the proton adds to one of the reacting aromatic species leaving the resonance stabilized secondary cation. This then adds to the ortho position o... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/6iMNA.png
The above reaction looks very similar to a conventional sulfonation reaction but if the reaction pathway is analogous to sulfonation I do not see how the $SO_2Cl^+$ would form. Surely $Cl^-$ would leave rather than $H_2O$ in the forma... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/2nx1N.png
I am struggling to find a mechanism for the above reaction. So far I have suggested that the proton adds to one of the reacting aromatic species leaving the resonance stabilized secondary cation. This then adds to the ortho position o... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/2nx1N.png
I am struggling to find a mechanism for the above reaction.
So far I have suggested that the proton adds to one of the reacting aromatic species leaving the resonance stabilized secondary cation. This then adds to the ortho positio... |
I've been given a problem asking:
>Estimate the standard enthalpy of formation of hydrazine, N2H4(g), from the following data.
>ΔHB(H2) = 436 kJ/mol ΔHB(N2) = 944 kJ/mol ΔHB(N–N) = 163 kJ/mol ΔHB(N–H) = 388 kJ/mol
While I know that ∆HB(N–N) refers to the energy released from breaking that bond, I'm not sure wh... |
This is a complex reaction, so don't feel bad about not "seeing" the solution right off.
Chlorosulfonic acid (or chlorosulfuric acid) is hazardous to work with and can give different products at different temperatures. At higher temperatures it generates $\ce{SO3}$ which will behave as an electrophile and react w... |
This is a difficult problem IMO, so don't feel bad about not "seeing" the solution right off.
Chlorosulfonic acid (or chlorosulfuric acid) is hazardous to work with and can give different products at different temperatures. At higher temperatures it generates $\ce{SO3}$ which will behave as an electrophile and re... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/6iMNA.png
The above reaction looks very similar to a conventional sulfonation reaction but if the reaction pathway is analogous to sulfonation I do not see how the $\ce{SO_2Cl^+}$ would form. Surely $\ce{Cl^-}$ would leave rather than $\ce{H_2O... |
How do I go about balancing these equations? |
Rob, IMO this is a difficult problem, so don't feel bad about not "seeing" the solution right off.
Chlorosulfonic acid (or chlorosulfuric acid) is both difficult and hazardous to work with so it's reactions aren't discussed all that frequently. It can also give rise to different products at different temperatures... |
The mass of Carbon 12 is 12u from definition, and is formed with 6 neutron, each with 1.0087u, 6 proton, each with 1.0072u and 6 electron, each with 0.0005u, which all add up to 12.0894u. why is there 0.7% difference? |
Isn't the mass of a carbon 12 equal to a mass of 6 neutron + 6 proton + 6 electron? |
I've been given a problem asking:
>Estimate the standard enthalpy of formation of hydrazine, $\ce{N2H4(g)}$, from the following data.
>\begin{align}
\Delta{}H_\mathrm{B}(\ce{H2}) &= 436~\mathrm{kJ/mol}\\
\Delta{}H_\mathrm{B}(\ce{N2}) &= 944~\mathrm{kJ/mol}\\
\Delta{}H_\mathrm{B}(\ce{N–N}) &= 163~\mathrm{kJ/mol}\... |
How to calculate the enthalpy of formation of hydrazine from tabulated values? |
If water, $\ce{H2O}$ is a covalent compound formed by sharing of electrons, why is it said (in case of fuel cells) that formation of water from hydrogen and oxygen is a redox reaction (transfer of electrons, not sharing). This would make it an ionic compound.
Any insights?
Note that, the concept of water being fo... |
I read in a biology course that you can determine the concentration of oxygen in water by adding some NaOH and then a small amount of MgCl. They say that a dark coloured precipitate is formed.
I can't see a way of writing this reaction. Can anyone help me? |
I read in a biology course that you can determine the concentration of oxygen in water by adding some $\ce{NaOH}$ and then a small amount of $\ce{MgCl2}$. They say that a dark coloured precipitate is formed.
I can't see a way of writing this reaction. Can anyone help me? |
![enter image description here][1]
[1]: https://i.stack.imgur.com/MtQDC.png
I need to find a mechanism for the above reaction but I cannot make much progress. I do have something in mind but it doesn't seem entirely plausible: First the tert-butyl group leaves (this seems wrong but tert-butyl cation is stable... |
I was reading [Cannabinoid Chemistry - 6.2 Extraction](http://www.rexresearch.com/hhusb/hh6thc.htm#HH62) & pondered over the following:
> Cannabis must be dried be(fore) it is extracted, because it is not possible to remove more than 50% of the cannabinoids from fresh material. THC-Acid is difficult to extract. If y... |
Why is decarboxylation done 'under nitrogen'? |
It's been confusing me for a while now , I know that reducing sugar contain aldehyde or ketone group . It's easy to identify them in monosaccharides but this becomes confusing in case of disaccharides![enter image description here][1]
[1]: https://i.stack.imgur.com/FoVM1.png
I fail to see carbonyl group here , ... |
How do you identify reducing / non-reducing sugar by looking at structure? |
Identifying reducing / non-reducing sugar been confusing me for a while now , I know that reducing sugar contain aldehyde or ketone group . It's easy to identify them in monosaccharides but this becomes confusing in case of disaccharides!
![enter image description here][1]
I fail to see carbonyl group here, How ... |
Why is the decarboxylation of 2-hydroxybenzoic acid (and related compounds) done 'under nitrogen'? |
Disclaimer: Potentially more of a physics question, but this area is muddy.
I'm trying to find 720 nm LEDs but they're proving to be very uncommon. In fact, there seems to be a gap between 660 nm up to ~730 nm. I've only been able to find one supplier of 720 nm LEDs (data sheet [here][1]). These LEDs also tend to be... |
Why are 720 nm LEDs so uncommon? |
Disclaimer: Potentially more of a physics question, but this area is muddy.
I'm trying to find 720 nm LEDs but they're proving to be very uncommon. In fact, there seems to be a gap between 660 nm up to ~730 nm. I've only been able to find one supplier of 720 nm LEDs (data sheet [here][1]). These LEDs also tend to be... |
![enter image description here][1]
[1]: https://i.stack.imgur.com/GvVIs.png
The above picture shows the first step of Oxymercuration. The electrons attack the Mercury atom but the OAc group leaves. Why is this? Hg is a transition metal with a number of available oxidation states, why cant it just accept the e... |
Why does the OAc group leave in the first step of Oxymercuration? |
We say :
$Alcohol\ \ \ \xrightarrow{\text{KMnO}_4}\ \ Acid$
The alcohol forms a carboxylic acid, ie gains an O from KMnO4. This means KMnO4 is a reactant! Then why is it written above the arrow?
What all do we write on arrow? |
What is meant by word on arrow? |
i.e: If you put a paper inside an oven vacuum packed and go beyond 250ºC, will burn? There's no oxidizer. If not, what will happen? |
Can paper burn without oxygen or air? |
I was solving some problems on chemical kinetics, then I was just struck at some ques of sequential reaction kinetics.
1) Given reactions $O_3+Cl\rightarrow O_2+ClO \cdots \cdots k_1=5.2 \times 10^9Lmol^{-1}s^{-1}$
and $ClO+O \rightarrow O_2+Cl \cdots \cdots k_2=2.6 \times 10^{10}Lmol^{-1}s^{-1}$
So, w... |
I was solving some problems on chemical kinetics, then I was just struck at some ques of sequential reaction kinetics.
Given reactions $$\ce{O_3 + Cl \rightarrow O_2 + ClO ~~~ k_1=5.2 \times 10^9~Lmol^{-1}s^{-1}}$$
and $$\ce{ClO + O \rightarrow O_2 + Cl ~~~ ~~~ k_2=2.6 \times 10^{10} ~Lmol^{-1}s^{-1}}$$
... |
This is the old Winkler titration, published as
*Die Bestimmung des im Wasser gelösten Sauerstoffes* by *Ludwig Wilhelm Winkler* in *Ber. Dtsch. Chem. Ges.*, **1888**, *21*, 2843-2854 ([SRC](http://gallica.bnf.fr/ark:/12148/bpt6k90715s/f46.image))
**How does it work?**
1. Add $\ce{MnSO4}$ to your water samp... |
Looking at compound D, one of the first things we notice is the carbonyl group. The carbon atom in a carbonyl is $\ce{sp^2}$ hybridized, so angle 6 involves an $\ce{sp^2}$ hybridized carbon. In such cases the $\ce{H-C-O}$ bond angle is ~ 120 degrees.
Just to elaborate a bit more:
- If you have four objects arr... |
The [Clark Type Oxygen Electrode][1] converts water, oxygen, and electrons into hydroxide via a hydrogen peroxide intermediate:
$$O_2 + 4 e^− + (2) H_2O → (4) OH^−$$
Which is the sum of:
$$(2) H_2O+O_2+(2)e^- \rightarrow H_2O_2 + OH^-$$
$$H_2O_2+(2)e^- \rightarrow (2) OH^-$$
Can this be reversed?
[1... |
Formation of O2, Water, and Electricity from Hydroxide? |
The [Clark Type Oxygen Electrode][1] converts water, oxygen, and electrons into hydroxide via a hydrogen peroxide intermediate:
$$O_2 + 4 e^− + 2 H_2O → 4 OH^−$$
Which is the sum of:
$$2 H_2O+O_2+2e^- \rightarrow H_2O_2 + OH^-$$
$$H_2O_2+2e^- \rightarrow 2 OH^-$$
Can this be reversed?
[1]: http://en... |
The [Clark Type Oxygen Electrode][1] converts water, oxygen, and electrons into hydroxide via a hydrogen peroxide intermediate:
\\[\ce{O2 + 4e^{−} + 2 H_2O -> 4 OH^{−}}\\]
Which is the sum of:
\\[
\begin{align*}
\ce{2H2O +O2 + 2e- &-> H2O2 + OH- \\
H2O2 + 2e- &-> 2 OH-}
\end{align*}
\\]
Can this be reverse... |
We say :
\\[\ce{Alcohol ->[\ce{KMnO4}] Acid}\\]
The alcohol forms a carboxylic acid, ie gains an $\ce{O}$ from $\ce{KMnO4}$. This means $\ce{KMnO4}$ is a reactant! Then why is it written above the arrow?
What all do we write on arrow? |
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... |
What are the minimum required given sets of information to complete an ICE chart for an equilibrium reaction? |
i.e: If you put a paper inside an oven vacuum packed and go beyond 250ºC, will it burn? There's no oxidizer. If not, what will happen? |
This is a rather physics question but I wanted to get an insight from a chemistry perspective. I heard from some that you can beat the speed or go faster than it but is that really true. Physicists as we all know look at the theoretical possibilities but what is your insight from a chemistry-ish view.
[Here][1] and... |
Can we really beat the speed of light? |
Formation of O₂, Water, and Electricity from Hydroxide? |
In [3:50 of this video][1] two FTIR spectras are shown. He explains that the % transmittance (double bond in his example) depends on the dipole moment, $\mu = \delta \cdot d$.
I understand that the center frequency depends on $\delta, d$, but why the **percentage** of transmittance depends on $\delta, d$?
[1]... |
Why the magnitude of dipole moment influences on FTIR % transmittance? |
In [3:50 of this video][1] two FTIR spectras are shown. He explains that the % transmittance (double bond in his example) depends on the dipole moment, $\mu = \delta \cdot d$.
I understand that the absorbance center frequency depends on $\delta, d$, but why the **percentage** of transmittance depends on $\delta, d$?... |
I was reading [Cannabinoid Chemistry - 6.2 Extraction](http://www.rexresearch.com/hhusb/hh6thc.htm#HH62) & pondered over the following:
> Cannabis must be dried be(fore) it is extracted, because it is not possible to remove more than 50% of the cannabinoids from fresh material. THC-Acid is difficult to extract. If y... |
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!... |
I was reading [Cannabinoid Chemistry - 6.2 Extraction](http://www.rexresearch.com/hhusb/hh6thc.htm#HH62) & pondered over the following:
> Cannabis must be dried be(fore) it is extracted, because it is not possible to remove more than 50% of the cannabinoids from fresh material. THC-Acid is difficult to extract. If y... |
I was reading [Cannabinoid Chemistry - 6.2 Extraction](http://www.rexresearch.com/hhusb/hh6thc.htm#HH62) & pondered over the following:
> Cannabis must be dried be(fore) it is extracted, because it is not possible to remove more than 50% of the cannabinoids from fresh material. THC-Acid is difficult to extract. If y... |
Yes, the overall reaction can be reversed. The reverse reaction is called the [oxygen evolution reaction](http://link.springer.com/referenceworkentry/10.1007%2F978-1-4419-6996-5_407) or simply [water oxidation](http://en.wikipedia.org/wiki/Heterogeneous_water_oxidation). Depending on the pH, you could write it as eit... |
I would like to spin coat Graphene oxide on the glass slides and intend to have a thickness of 100nm/0.1micrometre. May I know what is the amount of Graphene oxide to be poured onto the glass slides, spin time, spin speed and time for it to develop to obtain the optimized and desired thickness of 100nm? |
Why is the acidity order true ?
$CH3COCH3>CH3CO2CH3>CH3CON[CH3]2$
(I deduced that in 2nd and 3rd option
there is -I effect of methoxy group,$N[CH3]2$ and +R effect too
so the attached keto-carbon develops +ve charge
and the conjugate base become unstable due +R effect of methoxy and $N[CH3]2$ groups
is my logic ... |
Why is the acidity order true?
\\[\ce{CH3COCH3 > CH3CO2CH3 > CH3CON(CH3)2}\\]
I deduced that in 2nd and 3rd option
there is -I effect of methoxy group, $\ce{N(CH3)2}$ and +R effect too
so the attached keto-carbon develops +ve charge and the conjugate base become unstable due +R effect of methoxy and $\ce{N(CH3)2... |
Fructose is described to have a different metabolic pathway (a more fat-inducing one) than glucose (see: http://healthyeating.sfgate.com/difference-between-sucrose-glucose-fructose-8704.html) as it can only be metabolized by the liver and does not impact insulin.
What I don't understand, is that in glycolysis, a par... |
How is it that fructose has a different metabolic pathway than glucose but yet glucose is converted to fructose? |
Sigma bonds form due to the axial overlap of two orbitals whereas pi bonds form due to their lateral overlapping. Since the former is more effective, we can say that sigma is stronger than pi. We mean that the orbitals overlap to a further extent in sigma bonds and not as much in pi bonds(...or at least that is what I ... |
Is this a possible explanation as to why sigma bonds are stronger than pi bonds? |
I was reading [Cannabinoid Chemistry - 6.2 Extraction](http://www.rexresearch.com/hhusb/hh6thc.htm#HH62) & pondered over the following:
> Cannabis must be dried be(fore) it is extracted, because it is not possible to remove more than 50% of the cannabinoids from fresh material. THC-Acid is difficult to extract. If y... |
I'm preparing a chemistry show where I end the show with yellow powder bang..
The powder is a mixture of:
K2CO3 + KNO3 + S
My question is, what's the reaction between theese chemicals?
best regards
Jesper |
i saw a Youtube video which showed cotton (cellulose) dissolves in deep blue solution of tetramine copper made by adding 20% ammonia in copper carbonate salt. i tried to replicate the process using CuSO4 and copper chloride. none worked. what mistake i am doing? |
does tetramine copper dissolves cellulose? |
I'm preparing a chemistry show where I end the show with yellow powder bang..
The powder is a mixture of:
$K_2CO_3$ + $KNO_3$ + $S$
My question is, what's the reaction between these chemicals?
Best regards
Jesper |
I'm preparing a chemistry show where I end the show with yellow powder bang..
The powder is a mixture of:
\\[\ce{K2CO3 + KNO3 + S} \\]
My question is, what's the reaction between these chemicals?
Best regards
Jesper |
If a mixture of Mn$^{2+}$, Zn$^{2+}$, Co$^{2+}$, Ni$^{2+}$ and Al$^{3+}$ salts is dissolved in water, a white dim solution is obtained. I guess that the aluminium and zinc ions hydrolysed and the respective hydroxides are formed. Am I right, or maybe one of them won't hydrolyze so much that the solution becomes dim or ... |
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