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1500 questions
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What is the difference between "vapour" and "gas"?
I have read the definition of vapour on Wikipedia, but I don't seem to have a clear idea about the difference between a vapour and a gas. I know what it means when it says, "gas at a temperature lower than its critical temperature".
In this graph,…
gobbledy-gook
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Synthesis Golf XI: Hyperielliptone HA
It has been a little over a year since the last synthesis-golf was posted. I have talked to orthocresol and would like to help revive the tag!
A full FAQ post has been written on chemistry.meta.SE, explaining the premise of synthesis golf and the…
Eli Jones
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What is d-orbital collapse?
When I was perusing the works of Schwarz on atomic structure, I came across the unfamiliar term of d-orbital collapse.
He describes it as a variation in energetic sequence from group 1 to 3 elements such that the order changes from $\ce{4s < 4p <…
C. WJ
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What is the least dense liquid under normal conditions?
What is the least dense liquid under normal conditions, room temperature, one atmosphere of pressure, doesn't combust upon contact with air, also wouldn't kill a human just for being in the same room as it?
user78390
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Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?
This answer to the question Pre-mixing cryogenic fuels and using only one fuel tank written by a non-chemist (me) begins with:
At STP:
LOX's boiling point is 90.19 K
Methane's freezing point is 90.7 K
This does not a priori prove that a solution…
uhoh
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How to explain the concept of mol and reactions involving mol quantities
From time to time I do little pro bono lessons for second grade in math, physics, and chemistry. Recently I came across this question.
In a container is $2~\mathrm{mol}$ of $\ce{SO3}$ (sulfur trioxide). This compound under certain conditions breaks…
Anderson
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ICHO Synthesis Problem 2018
I've several doubts about this ICHO synthesis problem, which was a part of the preparatory problem package of 2018 (so yes, it's not a part of an ongoing contest)
Before sharing the answer given, I'd like to share my thoughts and efforts towards…
stoic-santiago
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Why are two three-membered rings preferred to a single five-membered ring in the reaction of a dihalide with alcoholic KOH?
The given answer is 1,1-dicyclopropylmethanone:
Step 1 is abstraction of acidic H by the strong base. Then, there's surely going to be anchimeric assistance. But there can be two places where the first carbanion can attack: either at the nearer…
Archer
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Synthesis Golf IX: Tezacaftor
A full FAQ post has been written on meta.chem.SE, explaining the premise of synthesis golf and the 'rules'. Please take a look at this before answering (if you haven't already).
The target of this Easter special round of synthesis golf is…
NotEvans.
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Why are arenes with conjoined benzene rings drawn as they are?
Whilst we are taught to represent benzene as below (A) due to its delocalised electrons, however when two benzene rings share carbons (e.g. naphtalene) it seems to be more commonly represented in textbooks as two conjugated rings (B). Whilst I…
Rory
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Why is the melting point of p-dichlorobenzene higher than those of o-dichlorobenzene and m-dichlorobenzene?
I was going through alkyl and aryl halides and noted the following statement in my textbook:
p-dichlorobenzene has higher melting point and solubility than those of o-dichlorobenzene and m-dichlorobenzene.
I thought over it but could not come to a…
Apurv
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How large is the energy difference between keto- and enol-form of guanine and uracil?
The nucleobases in DNA and RNA are generally present in the keto-form, and not in the enol-form. As an interesting historical note, James Watson and Francis Crick did initially believe them to adopt the enol-form, which isn't compatible with the…
Mad Scientist
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What happens to the argon in the Haber-Bosch process?
The Haber–Bosch process is used to synthesis ammonia from atmospheric nitrogen and hydrogen derived from a hydrocarbon such as methane. The process requires high temperatures and pressures and also requires repeated cycling of the gasses.
I would…
Slarty
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Is it correct to talk about an empty orbital?
Professor A. J. Kirby mentions:
The properties of an orbital are those of an electron contained in it. It is normal practice, illogical though it may sound, to talk of 'vacant orbitals'.The properties of vacant orbitals are those calculated for…
Tan Yong Boon
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Do chemists refer to water as "dihydrogen monoxide"?
Is the name "Dihydrogen monoxide" actually what chemists would use to refer to $\ce{H2O}$ (assuming there was no common name, "water")?
Of course, this is all over the internet. I'm a little skeptical though because the similar chemical $\ce{H2S}$…
user4553
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