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I'm using the Lennard-Jones potential for some (very simple) protein docking simulation and couldn't find parameters for different materials (like `C`, `N`, `O`, …). Is this because my [search engine of choice]-skills are lacking or because it doesn't make sense to differentiate between different materials when using a... |
I suppose that my problem is not one of great profundity, but it is an annoying one. The problem is related to the measurement units involved in rate equations of different order. Not being a chemist myself, I have in my work encountered equations of the type: -d[A]/dt = k [B]^b [A]^a representing the decay of some spe... |
Good day,
I need to know how to go about creating synthetic glucose with generally available materials. As I am aware of both photosynthesis and glucose in nature, I will not need lessons in how plants produce it. So, how may glucose be produced by artificial means?
Thank you. |
What Are The Steps To Creating Glucose? |
I premise, I'm a physicist and I'm working on a transfer procedure for graphene via CVD, which involves the use of PMMA as a resist layer. Studying this polymer, I still haven't found what is the cross-link temperature (or window of temperatures) for it. Can someone give me a hand? or just a good reference? |
I suppose that my problem is not one of great profundity, but it is an annoying one. The problem is related to the measurement units involved in rate equations of different order. Not being a chemist myself, I have in my work encountered equations of the type: $$\frac{-d[A]}{dt} = k [B]^b [A]^a$$ representing the decay... |
I suppose that my problem is not one of great profundity, but it is an annoying one. The problem is related to the measurement units involved in rate equations of different order. Not being a chemist myself, I have in my work encountered equations of the type: $$\frac{-d[A]}{dt} = k [B]^b [A]^a$$ representing the decay... |
I need to know how to go about creating synthetic glucose with generally available materials. As I am aware of both photosynthesis and glucose in nature, I will not need lessons in how plants produce it. So, how may glucose be produced by artificial means?
|
What are the steps to creating synthetic glucose? |
I'm using the Lennard-Jones potential for some (very simple) protein docking simulation and couldn't find parameters for different materials (like `C`, `N`, `O`, …). Is this because my [search engine of choice]-skills are lacking or because it doesn't make sense to differentiate between different materials when using a... |
I suppose that my problem is not one of great profundity, but it is an annoying one. The problem is related to the measurement units involved in rate equations of different order. Not being a chemist myself, I have in my work encountered equations of the type: $$\frac{-\mathrm{d}[A]}{\mathrm{d}t} = k [B]^b [A]^a$$ repr... |
According to this [article][1], the polymerization is determined by thermal initiator that is used in PMMA mixture. The polymerization (corsslinking) starts when the imitator is added to the mixture, but it is really slow at low temperature. Higher temperature lowers hardening time (speeds up the crosslinking). Since t... |
I'm using the Lennard-Jones potential for some (very simple) protein docking simulation and couldn't find parameters for different materials (like $\ce{C}$, $\ce{N}$, $\ce{O}$, …). Is this because my [search engine of choice]-skills are lacking or because it doesn't make sense to differentiate between different materia... |
Why is radium oxide yet to be isolated when a wide range of other radium (II) compounds are known ? |
I read that resonance in Toluene is initiated with the help of hyper-conjugation. Also hyper-conjugation is less stronger than Resonance/Mesomeric effect. But in toluene its resonance thats taking place with the help of hyper-conjugation right ? I am confused which has greater +R strength Toluene or Anisole? |
A galvanic cell consists of a standard hydrogen electrode and a copper electrode.
$\ce{2 H+ (aq) → H2 (g)}$ $E_O = 0.00 V$
$\ce{Cu^2+ (aq) + 2e- → Cu (s)}$ $E_O = 0.34 V$
Suppose the copper electrode is placed in a solution of unknown copper (II) concentration. The cell potential is measured t... |
According to this [thesis][1], the polymerization is determined by thermal initiator that is used in PMMA mixture. The polymerization (corsslinking) starts when the imitator is added to the mixture, but it is really slow at low temperature. Higher temperature lowers hardening time (speeds up the crosslinking). Since th... |
>5) Which one of the following metals does not react with hydrochloric acid?
>A. zinc
>B. magnesium
>C. iron
>D. copper
>E. aluminium
The right answer must be copper, but why doesn't copper react with hydrochloric acid while the other metals do?
|
The enthalpy of vaporization of [$\ce{HCN}$][1] is higher than for [$\ce{NH3}$][2], which suggest that HCN molecules interact more strongly than NH$_3$ molecules. C-H bonds are not usually considered good hydrogen bond donors, but HCN is unusual. For example $\ce{HCN}$ has a [pK$_a$ value of 9.2][3], indicating that t... |
Hybridisation is a purely mathematical concept, which makes it possible to explain experimentally found structures. The most prominent example for this is methane, where you can consider the central carbon atom to be $\mathrm{sp^3}$ hybridised. Formally, the $\mathrm{s}$ orbital and the three $\mathrm{p}$ orbitals can ... |
>"the most remarkable success of the Bohr's theory is that it provides a satisfactory explanation for the line spectrum of hydrogen."
But what is the problem with line spectrum of hydrogen which could not explained before the Bohr's theory was introduced and how it was explained by Bohr's theory? |
I think a good way to understand the importance of hybridization is to start with an illustration.
You have two structures: SnCl2 and SnCl4, and you are asked to rationalize why SnCl2 has a stronger bond than SnCl4 (this information is given). How would you do that?
Now there are two ways to approach this:
(Y... |
I'm using the Lennard-Jones potential for some (very simple) protein docking simulation* and couldn't find parameters for different materials (like $\ce{C}$, $\ce{N}$, $\ce{O}$, …). Does it even make sense to differentiate between different materials when using a crude approximation like the Lennard-Jones potential?
... |
Since this is pretty well covered in countless number of books and other sources I will try to just emphasise the key points.
1. The emission spectrum of atomic hydrogen was well known at that time, the only problem was that no one was able to explain it. :D Where does all this lines come from, i.e. what physical p... |
Since this is pretty well covered in countless number of books and other sources I will try to just emphasise the key points.
1. The emission spectrum of atomic hydrogen was well known at that time, the only problem was that no one was able to explain it. :D Where does all this lines come from, i.e. what physical p... |
The low energy portion (the part dealing with the $\ce{2s}$ and $\ce{2p}$ electrons) of the photoelectron (PE) spectrum of methane is reproduced below.
![enter image description here][1]
([image source][2])
The reaction being examined is the following one-photon process
$$\ce{CH4 + ~hv~ -> [CH4]^{+} + ~e^-}$$... |
I understand the basics of carbonic acid + 1 kcal breaking down into water and carbon dioxide.
However, my professor wants me to draw an energy map showing the catalyst in human blood reducing the activation energy from 21 kcal to 12 kcal. I've never run into an energy map nor have we discussed this catalyst in clas... |
The low energy portion (the part dealing with the $\ce{2s}$ and $\ce{2p}$ electrons) of the photoelectron (PE) spectrum of methane is reproduced below.
![enter image description here][1]
([image source][2])
The reaction being examined is the following one-photon process
$$\ce{CH4 + ~h\nu~ -> [CH4]^{+} + ~e^-}... |
I have to etch a very thin film (50nm) of Nickel (Ni) on a 100nm SiO2/Si substrate. Additionally, there is a ~5nm adhesion layer of Cr under the Ni that I'd also like to etch.
So I found [this page][1] which has a fairly long list of etches for Ni and Cr.
Ni:
>
1 : 1 : 1 - HNO3 : HAc : Acetone
1 : 1... |
What's the simplest way to etch Nickel? |
All molecular simulation force fields are essentially "fitted" mathematical functions. The parameters are adjusted until the simulation results match some physical properties we care about. As Geoff says, Lennard-Jones force fields are not particularly realistic, in the sense that you wouldn't expect a simulation of at... |
> why does the enol tautomerizes to the keto form?
**In 1,3-dicarbonyl systems, like the one pictured above, we would generally expect to have a measurable amount of the enol form present**. The keto-enol interconversion is an **equilibrium** and ratio of keto and enol will be guided by **thermodynamic** factors. ... |
Why does halogen-metal exchange happen? |
Why do halogen-metal exchanges happen? |
All molecular simulation force fields are essentially "fitted" mathematical functions. The parameters are adjusted until the simulation results match some physical properties we care about. As Geoff says, Lennard-Jones force fields are not particularly realistic, in the sense that you wouldn't expect a simulation of at... |
I think a good way to understand the importance of hybridization is to start with an illustration.
You have two structures: $\ce{SnCl2}$ and $\ce{SnCl4}$, and you are asked to rationalize why $\ce{SnCl2}$ has a stronger bond than $\ce{SnCl4}$ (this information is given). How would you do that?
Now there are two ... |
According to what I've learned so far, helium is in the first row of the periodic table, so its $n$ should always equal $1$. However, a question in my text asks about helium 2s. What is helium 2s? If helium 2s exists, why does the periodic table list helium in the first row instead of the second? |
Why isn't helium always He 1s? |
**Part 1:** According to what I've learned so far, helium is in the first row of the periodic table, so its $n$ should always equal $1$. However, a question in my text asks about helium 2s. What is helium 2s? If helium 2s exists, why does the periodic table list helium in the first row instead of the second?
**Part ... |
I know that orbitals are probability distributions. Are electron shells probability distributions too? |
Are electron shells probability distributions? |
A mixture is made by combining 110 mL of 0.15 M HCl and 215 mL of 0.055 M HI. What is the pH of the solution? |
How to find pH by mixing two solutions of different concentrations? |
> A mixture is made by combining 110 mL of 0.15 M $\ce{HCl}$ and 215 mL
> of 0.055 M $\ce{HI}$. What is the pH of the solution? |
> A mixture is made by combining 110 mL of 0.15 M $\ce{HCl}$ and 215 mL
> of 0.055 M $\ce{HI}$. What is the pH of the solution?
HCl --> H+ + Cl-
HI --> H+ + I-
According to what I thought , the molarity of H+ is the same as HCl because it is a strong acid and the mole ratio. So, I added the Molarity of both acids... |
> A mixture is made by combining 110 mL of 0.15 M $\ce{HCl}$ and 215 mL
> of 0.055 M $\ce{HI}$. What is the pH of the solution?
$$\ce{HCl -> H+ + Cl-}$$
$$\ce{HI -> H+ + I-}$$
According to what I thought, the molarity of $\ce{H+}$ is the same as $\ce{HCl}$, because it is a strong acid and the mole ratio. So, I... |
I came across alkaline ionized water as my aunts bought a system called Kangen Water from [Enagic Inc.][1] The water produced by this system is claimed to contain smaller water clusters (4-6 molecules) compared to tap water with 10-12 molecules. Besides, the ORP (Oxidation Reduction Potential) of the water is negative ... |
The Health Effects of Alkaline Ionized Water? |
In particular, how do a methylene more (in the case of the pentane) and a methylene less (in the case of the octane) make the difference in harmfulness to the environment in comparison with, respectively, the butane and the nonane?
I saw that butane and nonane are not classified as dangerous, but I have just done a... |
EDTA complexes with all the other metal ions in the periodic table except those from the group 1. Why is this so ? What is the coordination chemistry behind this ? |
Why doesn't EDTA complex with alkali metal ions? |
What is the product of this reaction, which I found in our high school textbook?
![enter image description here][1]
Initially
At first, I thought this was a typical Wolff-Kishner reduction, but then I saw the reagents didn't match up( no OH-). The answer given was quite perplexing to me :
![enter image descript... |
Almost everywhere I checked, the Inductive effect is described as a permanent effect with almost no mention of what that actually means.
- **What exactly is permanent about the effect?**
- If the effect is permanent, does that mean that even if the attached *electron
withdrawing/donating* group is remo... |
In what sense is the Inductive effect a permanent effect? |
I have to etch a very thin film (50 nm) of Nickel ($\ce{Ni}$) on a 100 nm $\ce{SiO2}$/$\ce{Si}$ substrate. Additionally, there is a ~5 nm adhesion layer of $\ce{Cr}$ under the $\ce{Ni}$ that I'd also like to etch.
So I found [this page][1] which has a fairly long list of etches for $\ce{Ni}$ and $\ce{Cr}$.
Ni:
... |
What's the simplest way to etch Nickel and Chromium sputtered layers? |
I have these two questions in my lab manual and I don't know how to approach them.
1. Which is the better solvent for molar mass determinations by freezing point depression, benzene or cyclohexane?
2. Which is the better method for molar mass determination, freezing point depression or boiling point elevation?
F... |
What is the product of this reaction, which I found in our high school textbook?
![enter image description here][1]
Initially
At first, I thought this was a typical Wolff-Kishner reduction, but then I saw the reagents didn't match up (no $\ce{OH-}$). The answer given was quite perplexing to me:
![enter image de... |
I was looking at two foam materials, where I had expected one to have closed pores.
Unfourtunately, the microscope was showing the upper layer of cut cells the same in both cases with no indication of differences in lower levels of the material.
By now, I suspect both are open-pored;
Is the difference clearly... |
How to distinguish open-pored polymer foam and foam with closed pores? |
I was looking at two foam materials, where I had expected one to have closed pores.
Unfourtunately, the microscope was showing the upper layer of cut cells the same in both cases with no indication of differences in lower levels of the material.
By now, I suspect both are open-pored;
Is the difference clearly... |
Here's a couple of examples of what I mean. Firstly, in the reaction with thionyl chloride to make a carboxylic acid:
![enter image description here][1]
Secondly, in this specific example of a hydroboration reaction:
![enter image description here][2]
I don't really understand why you cant attack from the... |
When a carboxylic acid acts as a nucleoplile, why does it attack through the carbonyl bond? |
I'm trying to calculate the energy required to dissociate a single $\ce{CO2}$ molecule into its respective elements, and I'm given that it takes $ 373.6 \times 10^{3} \, \, \mathrm{\frac{joules}{gram}} $ where $44.01$ grams is the mass of $6.022 \times 10^{23}$ molecules of $\ce{CO2}$.
By dimensional analysis:
... |
Any quantum number that represents the size of an orbital is a positive integer, $n$.
Any quantum number that represents the shape of an orbital is a non-negative integer, $l : l < n$.
Any quantum number that represents the orientation of an orbital, $m$, is an integer such that $|m| \leq l$.
Why do $n$ and... |
Why does the quantum number n limit the value of l, and why does l, likewise, limit the value of m? |
I'm wondering if it's worthwhile for me as an optical spectroscopist to read up a bit on EPR. Do EPR signals reveal where, in terms of wavelength, features in the optical spectrum can be expected to appear? I know it tells me
lifetimes of states, but that's about as far as I have dug into it. I have some EPR data on a... |
Can one figure out an optical absorption spectrum from EPR data? |
are eye drops with inactive ingredients called potassium chloride or sodium chloride the same as potassium dichromate and should I stop using those eye drops? |
I’m trying to understand how to solve this question for my physical chemistry class, but after many attempts, I am still not getting the same solution as the solution manual. If anyone can help me I’d greatly appreciate it.
The question is:
The solubility of mercury (I) iodide is $\mathrm{5.5\ fmol/L}$ in water a... |
A commercial solution would be a dye like IRF940A (from QCR Solutions) with an excitation maximum at $\lambda_{\mathrm{exc}} = 405\,\mathrm{nm}$ and an emission maximum at $\lambda_{\mathrm{em}} = 940\,\mathrm{nm}$. The supplier does not provide any information on the structure of the dye.
###What compounds are pro... |
I have chlorine tanks and they will be used industrially. When I use them, they will be exposed to all sorts of varying temperatures. I was wondering if there was any way that when I use them, I could figure out at what pressure I could release the Cl2, depending on the temperature, so that it remains a gas? I already ... |
How to determine at temperature and pressure to keep Cl2 a gas? |
I have chlorine tanks and they will be used industrially. When I use them, they will be exposed to all sorts of varying temperatures. I was wondering if there was any way that when I use them, I could figure out at what pressure I could release the $\ce{Cl2}$, depending on the temperature, so that it remains a gas? I a... |
I have always been led to understand that the mass of an element on the periodic table is the weighted average atomic mass over all naturally occurring isotopes. This seems to make sense with all the elements I have looked at except for uranium. Wikipedia's featured article on the element assures me that uranium's rela... |
How come uranium's relative atomic mass is 238.03 when it only contains isotopes with a mass number of 238 or less? |
In violin finishing technology alkali metal Rosinates are used in varnish synthesis.Ussually this alkali metal Rosinates are soluble in Turpentine. I also know that Copper, Zinc Rosinates are soluble in Diethyl ether. However, beside Turpentine I want to know if this alkali metal Rosinates (K, Na, NH4+ - Rosinates) are... |
In violin finishing technology alkali metal Rosinates are used in varnish synthesis. Usually this alkali metal Rosinates are soluble in Turpentine. I also know that Copper, Zinc Rosinates are soluble in Diethyl ether. However, beside Turpentine I want to know if this alkali metal Rosinates (K, Na, NH4+ - Rosinates) are... |
In violin finishing technology alkali metal Rosinates are used in varnish synthesis. Usually this alkali metal Rosinates are soluble in Turpentine. I also know that Copper, Zinc Rosinates are soluble in Diethyl ether. However, beside Turpentine I want to know if this alkali metal Rosinates ($\ce{K,\ Na,\ NH4+}$ - Rosin... |
Why do some crystal structure files not include bonds (the atoms are just placed in the respective position in the cell without bonds between any atoms)?
Shouldn't the bonds always be there?
Also, where can I look up these bonds?
|
Why do some crystal structure files not include bonds? |
Approximately 99.3% of uranium on Earth is the [$\mathrm{^{238}U}$ isotope](http://en.wikipedia.org/wiki/Uranium-238), and this specific isotope has an atomic mass of $\mathrm{238.05\ u}$, where $\mathrm{u}$ is the [atomic mass unit](http://en.wikipedia.org/wiki/Atomic_mass_unit), equivalent to 1/12 the mass of a $\mat... |
Recently I did a reaction in the lab (the reaction itself is not important) whose product was colloidal sulfur. As I watched the sulfur particles form I noticed something strange: At first the sulfur particles appeared white, but after a while the solution turned yellowish (probably when the size of the sulfur particle... |
**If you solve an x-ray crystal structure, you simply get a set of atomic positions. No more, no less.**
Often, the atomic positions don't include hydrogen atoms, only the "heavy" atoms.
Thus, most CIF (crystallographic interchange format) files, there *are* no defined bonds. Somewhere along the way, software *pe... |
My friend can buy polyurethane epoxy from his workplace for 3 dollars a litre, except that he doesn't know precisely the data sheet for it. His factory gets it in 20 ton deliveries.
It's difficult to mix because proportions are around 99% Polyurethane, 0.2% cobalt, and 0.8% of a toxic transparent catalyst liquid.
... |
Polyurethane epoxy resin chemistry advice please? |
My friend can buy polyurethane epoxy from his workplace for 3 dollars a litre, except that he doesn't know precisely the data sheet for it. His factory gets it in 20 ton deliveries.
He says that the mix has to be around 99% Polyurethane, 0.2% cobalt, and 0.8% of a toxic transparent catalyst liquid.
It's a generi... |
What is the product of this reaction, which I found in our high school textbook?
![enter image description here][1]
Initially
At first, I thought this was a typical Wolff-Kishner reduction, but then I saw the reagents didn't match up (no $\ce{OH-}$). The answer given was quite perplexing to me:
![enter image de... |
What is the product of this reaction, which I found in our high school textbook?
![enter image description here][1]
At first, I thought this was a typical Wolff-Kishner reduction, but then I saw the reagents didn't match up (no $\ce{OH-}$). The answer given was quite perplexing to me:
![enter image description her... |
Why is in the reaction of cyclic unsaturated aldehydes with hydrazine and hydrogen peroxide the aldehyde preserved? |
what is the functional group of zerumbone? |
Like Punarbasu Roy already stated, the depicted structures are certainly not the same. To be frank, only one of them (A) is correct, one of them is not completely wrong (B - but only because it is *incomplete*), and one is completely, utterly *wrong* (C).
In lieu of an actual crystal structure of ammonium hydrogenca... |
In IR spectroscopy, the x-axis is used to represent wavenumber, in cm<sup>-1</sup>. Why is wavelength, equal to 1/λ, used in place of wavelength, which is simply λ?
Sources I've already found explain why it was chosen rather than energy of waves, but the conversion from wavelength to wavenumber is never explained. ... |
Why is wavenumber used in IR Spectroscopy rather than wavelength? |
In IR spectroscopy, the $x$-axis is used to represent wavenumber, in $\mathrm{cm^{-1}}$</sup>. Why is wavelength, equal to $1/\lambda$, used in place of wavelength, which is simply $\lambda$?
Sources I’ve already found explain why it was chosen rather than energy of waves, but the conversion from wavelength to wave... |
Why is wavenumber used in IR spectroscopy rather than wavelength? |
I have met contradicting evidence. The phase diagrams show that CO2 solidifies at -78.5 C:
![enter image description here][1]
![enter image description here][2]
Wikipedia [confirms this][3]
> At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78.5 °C (−... |
At what temperature CO2 becomes solid at normal pressure? |
I have met contradicting evidence. The phase diagrams show that $\ce{CO2}$ solidifies at $-78.5 ^{\circ} \mathrm{C}$:
![enter image description here][1]
![enter image description here][2]
Wikipedia [confirms this][3]
> At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at tem... |
I have met contradicting evidence. The phase diagrams show that $\ce{CO2}$ solidifies at $-78.5\ ^{\circ} \mathrm{C}$:
![enter image description here][1]
![enter image description here][2]
Wikipedia [confirms this][3]
> At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at te... |
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