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2 answers
Edges of graphite
I've been asked this question a few times, and while I think I know the answer, I'd like to know more.
Graphite, as we know, is a sheet polymer. Since polymers are bound to be finite by physical considerations, graphite must have "edges". My…
ManishEarth
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Can nonpolar molecules exhibit dipole-dipole forces?
Dipole-dipole forces occur when the positive part of a polar molecule is attracted to the negative part of a polar molecule. In a nonpolar molecule, there may still be polar bonds, it's just that the dipoles cancel each other out. So why can't there…
carbenoid
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Neighbouring group participation with and without retention of configuration in nucleophilic substitution of 2,6-dichloro-9-thiabicyclo[3.3.1]nonane
Treatment of the dichloride A under the conditions indicated gives B with retention of configuration, while treatment of dichloride C gives D with inversion of configuration.
I am having difficulty drawing out the inversion ring product to find…
justbehappy
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16
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Why does bromine add to a double bond instead of a triple bond if both are present?
According to my textbook, the addition of bromine to pent-1-en-4-yne at low temperature yields 4,5-dibromopent-1-yne:
Why does bromination of the double bond occur selectively?
sudo_dudo
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16
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1 answer
Can an amide nitrogen be a hydrogen bond acceptor?
Can $\ce{N}$ (i.e. main chain $\ce{NH}$s of recognised residues in a peptide or protein) be a hydrogen bond acceptor? It is a well known fact that the main chain $\ce{NH}$s can be a hydrogen bond donor (as observed in the α-helix), but can they act…
mkHun
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16
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Why is benzoic acid a stronger acid than acetic acid?
Why is benzoic acid ($\mathrm{p}K_\mathrm{a} = 4.20$) a stronger acid than acetic acid ($\mathrm{p}K_\mathrm{a} = 4.76$), even though the conjugate base in case of benzoic acid is destabilized due to electron donation through resonance. Whereas…
Abhirikshma
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16
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1 answer
How important is it that geometry be optimized at a high level of theory?
I've been doing research with a computational chemist for a little while now and in one of our projects we are dealing with a rather large system and because I go to a relatively small university, our resources are limited. Thus, when we began to…
jheindel
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16
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2 answers
Why are aromatic compounds so stable?
I've never actually been told deeper reasons for this. In organic chemistry classes (1 and 2) we're usually told that aromatic compounds are very stable whereas anti-aromatic ones are not, and also, we're taught how to identify them. Why are they,…
Hritik Narayan
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Vapor pressure and boiling point for solutions in open containers
Question 1: If we have an open container which has water in it and is heated. If there is no lid over the container then how can this water ever boil as there will be no vapor pressure created over the water surface.
Question 2: What is the logic in…
user21683
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1 answer
By what mechanism do acids deprotect primary silyl ethers?
Standard protocols report the selective deprotection of primary silyl ethers in the presence of secondary silyl ethers under acidic conditions, as exemplary shown in scheme 1, a reaction by Hartmann and Kalesse.[1]
Scheme 1: Selective deprotection…
Jan
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16
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5 answers
Difference between state of matter and phase
What is the difference between state of matter and phase?
This site said that:
Phases are different from states of matter. The states of matter (e.g., liquid, solid, gas) are phases, but matter can exist in different phases yet the same state of…
Joe Academia
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2 answers
Why can NCl3 be hydrolyzed but CCl4 cannot?
While explaining why $\ce{CCl4}$ cannot be hydrolyzed, we say carbon atom doesn't have any d-orbitals and therefore a water molecule (lone pair electrons of $\ce{O}$ atom) cannot form coordinate bond with carbon. So, $\ce{CCl4}$ cannot be…
Edifice
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16
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Do coefficients matter in rate law?
For reaction $\ce{2A→B}$ (elementary step), according to the rate law, rate $= k [A]^2$.
In some calculations, we use $k[A]^2$ as the production rate of B. Why isn't it ${1 \over 2} k[A]^2$?
In this case, is the consumption rate of A also $k[A]^2$?…
Eiswein.Y
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16
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Why does gum get harder to chew after a while?
My Sister asked me this:
"Why is it that when we chew gum, it is soft and mushy to begin with , but slowly gets firmer and firmer like after 20 mins of chewing?"
I think it is because when we initially chew gum it has plenty of sugar causing…
The-Ever-Kid
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Is the Gibbs standard free energy always constant?
I am a biochemistry student and we are learning about thermodynamics. Is the Gibbs standard free energy for a reaction always constant? The equation below suggests that it changes with temperature:
$$\Delta G^{\circ\prime} = -RT\ln…
ctkw
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