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1500 questions
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What does "René" mean in René alloys?
René alloys are nickel-based super alloys (René 41, René 88, René N5 etc. etc.). But how did it get the name René? Is it an acronym or contraction of other terms? It was created by Earl Ross and the General Electric Materials Science group, so it…
BlueAshFlyer
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How to compute 2-electron integral for Hartree-Fock code?
I'm working on writing my own code for $\ce{H2}$ in an STO-3G basis set using Hartree-Fock (HF), and I am currently stuck on how to construct the two-electron integral matrix. I know how to evaluate the primitive two-electron integrals, but I can't…
SKB0514
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17
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1 answer
Why do bubbles form when it rains?
I noticed sometime ago that bubbles formed in puddles/streets whenever it rained. I am wondering if someone could tell me what could cause such bubbles. I examined the bubbles again today more closely and they didn't look "soapy". I know that is not…
CoffeeIsLife
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Aside from carbon, what other substances can be made "superhard"?
So diamonds are an allotrope of carbon, that is formed when carbon is put under immense pressure, right? What other elements or compounds can you make into "diamonds", as in more durable, harder versions of themselves? What happens if salt or iron…
ArborianSerpent
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17
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Why is water wet and fire hot?
This may be a silly question but why is water wet?
All the previous questions on water do not explain the reason why is water wet. They assume that its a natural property. However we need to understand why is it wet in the first place. This could…
user4060
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3 answers
Would the carbocation intermediate undergo rearrangement?
I have my concerns regarding option (a) in this question.
During the dehydration step, wouldn't the resulting carbocation intermediate formed in option (a) rearrange?
That is, the ring should contract from a $7$-carbon to a $6$-carbon one because…
Chem stack
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votes
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What is Fjord Region?
I'm studying molecular motors for a project of mine and I'm trying to understand what a Fjord region is.
It's sort of labeled in the image below but I'm not entirely sure which part.
I would like a suggestion of a book or article that may help me…
ChemDude
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1 answer
What's the difference between alpha-glucose and beta-glucose?
What's the difference between $\alpha$-D-glucose and $\beta$-D-glucose? Are they isomers? Or do they differ in their elemental composition?
a06e
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Can we synthesize alcohols by the photolysis of hydrogen peroxide?
As I was going through my revision of organic chemistry, I came across free radical substitution of alkanes with halogens. In a similar process where we use hydrogen peroxide, instead of chlorine, so that photolysis would yield a hydroxide radical…
Pritt says Reinstate Monica
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Is Mg(OH)2 more insoluble than MgCO3?
In removing temporary hardness by boiling, $\ce{Mg(HCO3)}$ is converted to $\ce{Mg(OH)2}$ but not $\ce{Mg(CO3)}$. The answer that I found in our coursebook was that it has a higher solubility product, but if its solubility product is higher, then it…
Nehal Garg
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3 answers
What is hydrogen-rich water?
My question is: Is hydrogen-rich water true? I am aware of the alkaline water. I have read several articles in the Internet regarding this kind of water but I cannot seem to be convinced. Wikipedia isn't even talking about it.
I am puzzled with how…
Lester Nubla
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5 answers
Why is Charcoal such an excellent adsorbent?
Charcoal (also activated charcoal) is known to adsorb a huge variety of substances including a variety of paints, dyes and many different kinds of ions. Moreover, the amount of adsorption at normal pressure and temperature is high. I know…
stochastic13
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4 answers
Hybridization of nitrogen in trisilylamine, (SiH3)3N?
I want to know the hybridization of the central atom in $\ce{(SiH3)3N}$.
I think it should be $\mathrm{sp^3}$, because $\ce{N}$ is attached to three silicon atoms and one lone pair. But actually it is supposedly $\mathrm{sp^2}$.
How is this so?
hey
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After a unitary transformation, is Koopmans' theorem still valid?
Koopmans' theorem says that the energy of the HOMO of the Hartree-Fock orbitals is equal to the first ionization energy of whatever system is being studied. This is only approximate because it assumes no changes in the orbitals in the ionic state,…
jheindel
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Why do post-Hartree-Fock methods fail to predict the direction of the dipole moment of carbon monoxide?
In carbon monoxide the dipole moment (negative to positive) points towards the oxygen, as I explained it in How can the dipole moment of carbon monoxide be rationalised by molecular orbital theory?
A calculation using density functional…
Martin - マーチン
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