instruction stringlengths 15 21.8k |
|---|
Coming from a DFT background, I'm used to the concept that the DFT eigenvalues do not correspond to excitation energies (i.e., the band gap, ionization potentials, etc.). To correct for these it's common to go to many-body approaches like the GW approximation to the self-energy, which is said to explicitly deal with qu... |
#Why is water wet?
Chemically speaking saying that water is wet has not much sense.We could however say that _"Wetting process"_ is caused by the presence of a thin liquid particles layer over a material. In our specific case this depend from the chemistry of water and the chemistry of skin. So the main causes of... |
My question is, if "gas" belongs to "State of Matter" then what does "Metal" belong to.
Gas can be substituted with any state of matter(in the analogy); metal can be substituted with metalloid or nonmetal(in the analogy). I've researched this and I can't seem to find an answer to this. So, this could read as "if 's... |
This is a great question and I love it. Thank you for taking the time to not only post the question but each attempted response. I will try to address the parts of this question that I can at the moment. I will list, in order, your attempted answer along with my response.
----------
**(i)** Carbene H2C: has tw... |
This is a great question and I love it. Thank you for taking the time to not only post the question but each attempted response. I will try to address the parts of this question that I can at the moment. I will list, in order, your attempted answer along with my response.
----------
**(i)** Carbene H2C: has tw... |
I am trying to verify the results of EPA method 26A (http://www.epa.gov/ttnemc01/promgate/m-26a.pdf). The Method claims to be able to separate and quantify a mixed halogen/halide gas stream. Although I believe the chemistry holds true for Cl₂/HCl and Br₂/HBr, I'm not so sure about F₂/HF. Despite the Method not mentioni... |
Can F2/HF be separated using acid/base solutions in series? |
There are a number of things I don't understand about Ionic equations.
First off, when you do net ionic equations, is it correct that you're only focusing on precipitates? The way I understood it, you put "no reaction" if there are no solid or gaseous products. To clarify, if all of the products of the reaction are ... |
Total and Net Ionic Equations? |
Below is a copy of the method I am using to determine electron configurations.
![][1]
[1]: https://i.stack.imgur.com/K3mbW.jpg
I started doing some practice questions (unfortunately there were no answer keys attached to it -- so I consulted google for the correct answers).
I just came across the questi... |
Where is it possible to get titanium and does it need to be extracted? I would please like to know |
Where is it possible to get titanium and does it need to be extracted? |
Lysergic acid diethylamide (LSD) is a well known hallucinogen and (usually) illegal psychoactive drug with the structure below:
![enter image description here][1]
The drug is active is doses measured in *micrograms* in contrast to many other active compounds where the dose is milligrams or even grams. The effecti... |
What chemical properties make LSD so psychoactive? |
The answer is approximately 6.88. Therefore a $1\ M$ solution of glycerol in water will be ever so slightly acidic (considering that the hydroxyls are much weaker bases than acids, i.e. that the equilibrium constant for the reaction $\ce{C3H7O2OH + H2O <=> C3H7O2O^- + H^+}$ is much smaller than the constant for $\ce{C... |
Do natural or human engineered enzymes exist that can speed up the break down metals (element, compounds & alloys)?
If no, then what biological or chemical construct can break down metals in the same way that enzymes break down food in a person's stomach? |
Are there enzymes found in nature or the man made world that can help break down metals? |
An electrode can be plated by having a solution full of electrolyte, using the the metal that will receive the plating as the cathode, and the metal doing the plating as the anode. Current is put through the cell and the anode dissolves oxidized metal ions into the solution, which gravitate over to the cathode, and the... |
What prevents the anode from corroding in electrolytic organic reactions? |
Is there an algorithm for finding the number of cyclic isomers a given compound might have?
I've found a general algorithm for all isomers: http://www-jmg.ch.cam.ac.uk/data/isomercount/isojava.html, but I'm not sure how to apply it for cyclic isomers only. |
The answer is approximately 6.88. Therefore a $1\ M$ solution of glycerol in water will be ever so slightly acidic (considering that the hydroxyls are much weaker bases than acids, i.e. that the equilibrium constant for the reaction $\ce{C3H7O2OH + H2O <=> C3H7O2O^- + H3O^+}$ is much larger than the constant for $\ce{... |
Consider two alcohols:
$$\rm{CH_3 - CH_2 - OH }$$
and
$$\rm{CH_3 - CHOH - H }$$
In the second alcohol, the hydroxyl radical instead of sticking out from the molecule, is bonded below the terminal carbon, like this
$$\rm{H}$$
$$|$$
$$\rm{R- C- H}$$
$$|$$
$$\rm{OH}$$
Now, this doesn't affect the no... |
Does the position of the functional group on the terminal carbon change the nomenclature? |
I am asking this because I have a review question in my physics class which gives me a multiple-choice question. I have heard and seen elsewhere on the internet (such as wikipedia) that chemistry is the study of reactions and the properties of matter. That is usually a satisfactory answer, but for whatever reason thi... |
What is chemistry considered the study of? |
My answer is iodoethane and tert-butanol, but the correct answer is ethanol and 2-iodo-2-methylpropane.
I know that the ethyl side goes by an SN2 mechanism because it is a primary R group, and the t-butyl group would be SN1 because it is tertiary. However, why would the SN2 reaction not happen first? |
In cleaving ethers with both SN1 and SN2, which occurs first? |
In cleaving ethers with both SN1 and SN2 mechanisms possible, which occurs first? |
Was looking at Henry's law and Raoult's law
constants and there seemto be lots of
equations involved.
Henry's law involves partial pressure and the latter involves the vapor pressure.
Wondering what the difference is? |
What is the differences between partial pressure and vapour pressure? |
I want to know how the following sigma bond strength values are calculated.
Like S-S = 1.0, S-P=1.71 And P-P=3.0.
How these 1.0, 1.71, 3.0 came? |
From a chemistry point of view, if dental amalgam is a compound of mercury and other metals, and compounds are elements which are chemically bonded, how would it be possible for mercury to "leak out" of fillings if no further chemical reaction would be taking place? |
Why do some dentists claim mercury "leaks out" of amalgam fillings? |
Mercury vapors are released. It has long since been proven that people with mercury in their teeth constantly have small portions of mercury vapor evaporating from the tooth. There's many videos of this taking place. It's not a mystery.
https://www.youtube.com/watch?v=hqIdGwAMxxs |
I'm looking at purchase orders and I see purchases for chemicals like the following.
Glutaraldehyde, EM Grade, 25%
What does the "EM Grade" mean in this text? It says that it's recommended for histological or immunological techniques, but how?
mj |
I'm looking at purchase orders and I see purchases for chemicals like the following.
Glutaraldehyde, EM Grade, 25%
What does the "EM Grade" mean in this text? It says that it's recommended for histological or immunological techniques, but how?
|
## Silly answer
There is no enzyme that grinds down an Airstream, but an alligator might do the job!
## Serious (but disappointing) answer
In nature, most metals seem to exist as oxides, sulfides, carbonates, halides, etc. and not as bare metals. Consequently, there was/is probably little evolutionary benefit in t... |
The answer is approximately 6.88. Therefore a $1\ M$ solution of glycerol in water will be ever so slightly acidic (considering that the hydroxyls are much weaker bases than acids, i.e. that the equilibrium constant for the reaction $\ce{C3H7O2OH + H2O <=> C3H7O2O^- + H3O^+}$ is much larger than the constant for $\ce{... |
What is the general thermal conductivity of animal skin leather?
I understand there are many different animal's skins (cow, sheep, buffalo, dear, pig), but in general, does natural leather insulate well (compared to, for scale, an esky for food insulation), or not? |
How well (or how poorly) does natural leather insulate? |
How well (or poorly) does natural leather insulate? |
While the answers so far are not wrong, I'd like to add a refinement. Chemistry is the study of matter at the level of *electron interaction*. The basic question in chemistry is about *chemical bonding*, and as far as we know this is a function of electron interaction. In contrast, radioactivity is also about matter, b... |
I'm curious to know, what exactly does the 3,4 part of 3,4-methylenedioxymethamphetamine represent? |
>In a mixture of gases, each gas has a partial pressure which is the hypothetical pressure of that gas if it alone occupied the volume of the mixture at the same temperature. </br>
What does this mean? For example, if we have a mixture of gases $A$, $B$ and $C$ in an isolated room, then, according to [Dalton's law... |
>In a mixture of gases, each gas has a partial pressure which is the hypothetical pressure of that gas if it alone occupied the volume of the mixture at the same temperature. </br>
What does this mean? For example, if we have a mixture of gases $A$, $B$ and $C$ in an isolated room, then, according to [Dalton's law... |
What is the general thermal conductivity of animal skin leather?
I understand there are many different animal's skins (cow, sheep, buffalo, deer, pig), but in general, does natural leather insulate well (compared to, for scale, an esky for food insulation), or not? |
If you titrate some hydrogen bromide solution to some sodium hydroxide in order to determine the exact concentration of hydrogen bromide... And you use An anthocyanins as pH indicator. This anthocyanin will be red if you have a low pH value. It will be purple if it is slightly acidic till it is slightly basic.It will b... |
An anthocyanins as pH-indicator: stop the titration at red, purple or blue? |
This is a little review of the online definition I've found:
[Oxford Dictionaries](http://www.oxforddictionaries.com/definition/english/chemistry?q=chemistry) definition:
> The branch of science concerned with the substances of which matter is
> composed, the investigation of their properties and reactions, and ... |
What are the products when tert-butyl ethyl ether is cleaved with concentrated HI?
My answer is iodoethane and tert-butanol, but the correct answer is ethanol and 2-iodo-2-methylpropane.
I know that the ethyl side goes by an SN2 mechanism because it is a primary R group, and the t-butyl group would be SN1 becaus... |
Quite often (from my own experience anyway), one of the safety rules in a school (high school or university) laboratory is that the students must wear leather shoes.
I like to demonstrate some of the safety rules, so my question is, **what is an effective and safe experiment to demonstrate the safety of wearing le... |
What is an effective experiment to demonstrate the safety of wearing leather shoes while experimenting in the chemistry lab? |
If you titrate some hydrogen bromide solution to some sodium hydroxide in order to determine the exact concentration of hydrogen bromide... And you use An anthocyanins as pH indicator. This anthocyanin will be red if you have a low pH value. It will be purple if it is slightly acidic till it is slightly basic.It will b... |
If you titrate some hydrogen bromide solution to some sodium hydroxide in order to determine the exact concentration of hydrogen bromide... And you use An anthocyanins as pH indicator. This anthocyanin will be red if you have a low pH value. It will be purple if it is slightly acidic till it is slightly basic.It will b... |
In molecular orbital theory, the fact that a bonding and antibonding molecular orbital pair have different energies is accompanied by the fact that the energy by which the bonding is lowered is less than the energy by which antibonding is raised, *i.e.* the stabilizing energy of each bonding interaction is less than th... |
If you titrate some hydrogen bromide solution to some sodium hydroxide in order to determine the exact concentration of hydrogen bromide, and you use anthocyanins as a pH indicator. This anthocyanin will be red if you have a low pH value and purple if it is slightly acidic until it is slightly basic. It will be blue if... |
Anthocyanins as pH-indicators: stop the titration at red, purple or blue? |
How does titanium occur in nature?
Is it available as a native metal or only in the form of ores?
Which precesses are typically used to convert the natural resources to the solid metal?
Any hints on where to find further information are welcome. Thank you very much in advance. |
How is titanium metal obtained from natural resources? |
First of all, I don't understand why you would titrate the acid of unknown concentration to your base of known concentration, I've learned it the other way around.
Now, following my proposal, we have our solution of $\ce{HBr}$ waiting to be titrated with $\ce{NaOH}$. Since sodium hydroxide is a fairly strong base, w... |
I have a problem solving reaction of ethers with reagents like RX(X= halide).In some reactions they follow $SN_1$ and in some reactions they follow $SN_2$.So i want to know when do they follow $SN_1$ and when do they follow $SN_2$?Please provide with a link or pdf with example if possible.Thanks in advance. |
Which mechanism do ethers follow? |
I am not aware of ethers reacting in substitution reactions with alkyl halides $(\ce{RX})$ as the electrophiles. Ethers are exceptionally poor nucleophiles.
However, ethers do react with the hydrohalic acid $(\ce{HX})$ to form alkyl halides by nucleophilic substitution.
>The first step of this reaction is always... |
I noticed that distilled water works well to clean away fingerprints on touchscreens or oil stains on a ceramic field after frying an egg.
But water and oil/fat are not supposed to mix, so why does that even work? |
Distilled water to clean greasy stains: Why does that work? |
I learned in class that the equivalence point in an acid-base titration is reached when the solution contains equal number of moles of $OH^-$ and $H^+$ ions. However, in a weak acid and strong alkali titration, the $pH$ at equivalence point (when I added the right amount of acid and alkali to make it a neutral solutio... |
pH at equivalence point? Souldn't it alway be pH 7? |
Why don't metals form covalent bonds in bulk metal? |
Two kinds of reactions have to be considered:
1. Neutralisation of the weak acid with the strong base
2. Secondary reactions from the products
The neutralisation is fairly straightforward:
$$\ce{HA + NaOH -> NaA + H2O} $$
However, and here comes number two from the list: It doesn't just stop there, because... |
I learned in class that the equivalence point in an acid-base titration is reached when the solution contains equal number of moles of $\ce{OH-}$ and $\ce{H+}$ ions. However, in a weak acid and strong alkali titration, the pH at the equivalence point (when I added the right amount of acid and alkali to make it a neutr... |
Shouldn't the pH at the equivalence point always be 7? |
Take this nictotine molecule:
![enter image description here][1]
And this mass spectrum:
![enter image description here][2]
I'm not sure how to explain all the peeks.
This might explain the peek at 42:
![enter image description here][3]
But can this peek als be explained by something else in t... |
How does mass spectroscopy of nicotine work? |
Take this nicotine molecule:
![enter image description here][1]
And this mass spectrum:
![enter image description here][2]
I'm not sure how to explain all the peaks.
This might explain the peak at 42:
![enter image description here][3]
But can this peek als be explained by something else in th... |
If you titrate some hydrogen bromide solution (0.1 M) to some sodium hydroxide in order to determine the exact concentration of hydrogen bromide (0.1 M), and you use anthocyanins as a pH indicator. This anthocyanin will be red if you have a low pH value and purple if it is slightly acidic until it is slightly basic. It... |
I don't know what exactly are the compounds that causes urine to be smelly, but does it (or do they) have higher or lower boiling points than water? If I have both liquid and exposed them to open air, will the water dry up first or will the smell disappear first? |
Smelly matters in urine - do they have lower or higher boiling point than water? |
Take this nicotine molecule:
![enter image description here][1]
And this mass spectrum:
![enter image description here][2]
I'm not sure how to explain all the peaks.
This might explain the peak at 42:
![enter image description here][3]
But can this peek als be explained by something else in th... |
Assuming a perfect diamond with no impurities. Would this diamond considered to be a single large molecule?
Browsing the interweb I found several opinions about this but did not find a clear Yes or No.
From what if gathered so far I'm pretty sure a diamond is a monocrystalline solid. Since all its parts are connect... |
Is a diamond a single molecule? |
I've decided to tackle this question in a somewhat different manner. Instead of giving the chemical intuition behind it, I wanted to check for myself if the mathematics actually work out. As far as I understand, this isn't done often, so that's why I wanted to try it, even though it may not make the clearest answer. It... |
[This recipe][1] for home-made handwash (liquid soap) consists of bar soap, water, Epsom salts, and coconut oil.
The author specifically warns against using 'artificial' Epsom salts, preferring the naturally occurring type, because the 'artificial' type is *supposedly* contaminated by heavy metals incl. arsenic.
... |
Epsom salts - heavy metal contamination myth? |
The transition metals have valence and penultimate shell incompletely filled . so does this mean that the transition metals first fill up their valence shell and then penultimate shell? |
I'm reading on ionic crystal structures and am confused by this from my textbook:
> Because the metallic elements give up electrons when ionized, cations are ordinarily smaller than anions
I understand that having a positive charge will pull the electrons closer, but shouldn't the atom from the larger period (row... |
Why are cations ordinarily smaller than anions? |
I think that I understand most of the parts of the symbol shown for ground state oxygen![Oxygen term symbol in ground state][1]
[1]: https://i.stack.imgur.com/ADeqT.png
However, I was hoping that someone could tell me what exactly the negative superscript sign means? And how do you identify between a positive... |
I just read that acetic acid is an exception to the general idea that the conjugate base to a weak acid is a strong base. The example says that the conjugate base of a weak acid will only be strong if the acid is a weaker acid than water.
What I'm curious about though, is if acetate is a weak base due to its resona... |
Is acetate a weak base due to its resonance structure? |
What are the units of your answer? You need a solubility, which is an amount per volume. If your amount is moles, the your solubility is in moles/liter: $\text{M}$.
That unit appears in the Henry's Law constant! $6.1\times 10^{-4} \frac{\text{M}}{\text{atm}}$. What can you do to get rid of the atmospheres in the de... |
From my book:
"When white light shines through a solution of a complex ion of a transition metal, photons of a particular frequency are absorbed and their energy promotes an electron from lower energy level to upper energy level. We see the complementary color to the light absorbed"
my question:
1. Once the elec... |
Are ligand exchange reactions one-way reactions or reversible? I know this is a very silly question but its not said outright in any place...
For example, in my high school chemistry book, these two ligand exchange reactions are shown:
$$[Cu(H_2O)_6] + 4Cl(aq)^- <=> [CuCl_4]^{2-} (aq) + H_2 O(l)$$
$$[Cu(H_2O)... |
Ligand exchange reactions... are they one way or reversible? |
I am not a pro, but I have some experience with gaussian. For example, I can optimize a structure, calculate the frequency and rotational energies.
In the lab I made a nucleophilic substitution reaction where the Nucleophile X reacted with R-alkyl-CH2-I to form R-alkyl-CH2-X (iodide was eliminated). However, my mole... |
I'm reading about ionic crystal structures with planes of close-packed anions and the interstitial sites for cations. There are two types of interstitial sites: tetrahedral and octahedral. That makes perfect sense. What confuses me is this:
> for each of these anion spheres, one octahedral and two tetrahedral positi... |
Why is there one octahedral and two tetrahedral positions for every anion in a close packed structure? |
There is a group R an organic group connected to either Oxygen or Nitrogen.R is such a group which has almost zero electronic effects(Resonance effect and inductive effect).I want to ask if N or O are to donate a lone pair then which one will have higher donating capacity?According to my opinion it should be Oxygen as... |
At what amount is digesting soap unhealthy? |
Have anybody synthesized di- or higher nitrated cyclopentadienes possibly with methyl or other groups in the 1 position (analogs of TNT)? |
Are highly nitrated cyclopentadiene compounds possible? |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.