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1500 questions
16
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2 answers
Why doesn't the viscosity of water change much with temperature like it does for other substances?
I would like to know why water doesn't ever become like syrup before it freezes when many other liquids, such as hydrocarbons, seem to have a more gradual change from becoming more viscous and then turning solid.
As I understand it, the more…
Klik
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16
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What is Sodium Chloride like in gas state?
Since sodium chloride is sodium and chlorine atoms bonded as a lattice and there are no discrete molecules, doesn't that mean in gas state, sodium chloride is simply sodium and chlorine atoms separate from each other, resulting in a mixture of…
Rishi
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16
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How did Mendeleev know elements from compounds or mixtures?
I read that Mendeleev initially thought didymium was an element, but it was actually a mixture.
How did he know the rest of the chemicals in the periodic table were elements and not compounds, especially since back then most elements would have been…
Paddyseo
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16
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1 answer
What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan?
What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan?
Over on the Skeptics StackExchange, a question has come up about charging Lithium-ion cells to just 80% of their maximum, in order to…
410 gone
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16
votes
4 answers
How can you build a model of tetrahedral coordination from objects found at home?
Our college is switching to teaching online mid-semester in hopes of slowing the spread of Covid-19. All the molecular model kits are still on campus. How could you build a model of tetrahedral coordination (say methane) from materials found at…
Karsten
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16
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3 answers
Are there any datasets containing molecules with more than 38 heavy atoms?
I have been testing a machine learning approach for molecular energy prediction. The current dataset that I have is QM9, which is consist of molecules with up to 9 heavy atoms.
I was wondering if anyone knows of available datasets that contain…
Blade
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16
votes
2 answers
How were x-ray diffraction patterns deciphered before computers?
I know the general idea behind x-ray crystallography is to take a high quality crystal and place it in the path of an x-ray beam. Areas of high electron density will diffract the beam and lead to spots on a detector screen where photons have…
Joe
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16
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1 answer
What is quasi-aromaticity?
During my study of aromaticity, I came through this topic of quasi-aromaticity. Can you please elaborate what Quasi aromatic compounds are and how are they designated?
chail10
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16
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2 answers
Why are palladium and platinum carbonyls unstable at room temperature?
By palladium and platinum carbonyls, I mean the mononuclear, homoleptic, charge-neutral, binary carbonyl complexes of the form $\ce{M(CO)_n}$ and not any heteroleptic complexes like $\ce{Pd(CO)(PPh3)3}$ and similar compounds of platinum which are…
Nilay Ghosh
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16
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1 answer
Using a gas stove instead of Bunsen burner for a flame test?
In all chemistry labs we use the Bunsen burner. What's the difference between it and a good old gas stove used in home? Can the stove also be used to get positive flame tests for some cations (like $\ce{Ca^2+}$)?
evamPUNdit
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16
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2 answers
What is the IUPAC preferred name of this tetracyclic natural product?
On page 819 of Vollhardt, Organic Chemistry 7th Ed., the following "subunit of the antibacterial platensimycin" appears. I have attempted to apply von Baeyer and skeletal replacement ('a') nomenclature but am stuck deciding between numberings. Here…
holomenicus
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16
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2 answers
Why does hand sanitizer turn into a liquid after coming out of the bottle?
Hand sanitizer is a gel in its bottle, but when I pour it on my palm, it turns into a free flowing liquid. Why does that happen?
It doesn't turn to a liquid when I pour it on my floor or my table. It doesn't seem to be related to heat, as I tried…
duci9y
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16
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4 answers
Reasons for negative iodoform test
Why does 2',6'-dimethylacetophenone not give iodoform test?
lowkeyy
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16
votes
5 answers
Define, (actually define) the "stability" and "energy" of a compound
When we say a conformer or compound is of "higher energy" than another, are we quantifying energy in terms of the bond strength? Or are we going off of how much energy it takes to break the bond? I don't think we can just assign energies to each…
H.M
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16
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1 answer
What's this glassware?
Can anybody tell me what this glassware with a stem, bulb and long tube is?
Alexander
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