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1500 questions
19
votes
3 answers
Why is heating increasing the solubility of sodium hydroxide?
\begin{align}
\ce{NaOH &-> Na+ + OH-} & \Delta H^\circ &= \pu{-44.51 kJ/mol}
\end{align}
The dissolution of sodium hydroxide in water is an exothermic process, and so, according to Le Chatelier’s principle, cooling the container should shift the…
LanguagesNamedAfterCofee
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19
votes
1 answer
Creating energy profile diagrams for publication
Is there automated software to create energy profile diagrams like the ones below?
One could use something like Illustrator or Inkscape, but they aren't automated, are expensive (Illustrator), are difficult to use, and wouldn't be practical for…
pentavalentcarbon
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19
votes
2 answers
Why don't free radicals undergo rearrangement like carbocation/carbonium ions do?
Why don't free radicals and carbanions undergo rearrangement like carbocation/carbonium ions undergo in a reaction?
Dimenein
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19
votes
1 answer
Reaction of furan with chloroform in base
This reaction looks like the Riemer-Tiemann reaction. The only difference is the reactant. First step is the formation of carbene. Second step involves the attack of π-electrons of furan on the vacant orbital of carbene which results in two…
Aditya Dev
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19
votes
2 answers
How can titanium burn in nitrogen?
I was going through the properties of titanium when a certain thing caught my eye: It was the reaction of burning of titanium in nitrogen. I was astonished to read it as I knew that neither is nitrogen a supporter of combustion nor does it burn…
Abhi
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19
votes
3 answers
Computing two-electron integrals with an STO-3G basis set
I am trying to implement a restricted Hartree-Fock calculation using an STO-3G basis set, for fun. I managed to perform this calculation where only $\mathrm{1s}$ orbitals are present ($\ce{H2}$ and $\ce{HeH+}$) as explained in Szabo and Ostlund's…
user23061
19
votes
1 answer
How can the gauche-effect be explained?
Generally, anti-conformations are more stable. But in the case of 2-fluoroethanol, the gauche confirmation is more stable.
It's given in March's advanced organic chemistry book that intramolecular hydrogen bonding is not the correct reason for the…
Aditya Dev
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19
votes
4 answers
Will adding up protons and electrons (without neutrons) create a new element?
If protons have a positive charge and electrons have a negative charge,
can we add up several protons and electrons together to create a new element, without adding neutrons to hold the nuclei together?
soundslikefiziks
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19
votes
3 answers
How to evaluate the heat of formation with computational chemistry?
I'm sorry if this is a stupid question, but since I'm a beginner with computational chemistry, please, be patient.
Let's consider the reaction of formation of water:
$$\ce{1/2 O2(g) + H2(g) -> H2O(g)}$$
This reaction shoud give a $\Delta_\mathrm…
HCSthe2nd
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19
votes
1 answer
Is there any experimental evidence for OClF5?
On page 88 and 89 of this document, the author laments that $\ce{OClF5}$ has still not been discovered. He says it would be "just about the ultimate possible storable oxidizer" (for rockets).
(Note: it's pages 88 and 89 as labeled by the writing on…
DrZ214
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19
votes
6 answers
Do atoms form either a positive or a negative charge, but not both?
I do not mean at the same time, of course, but I mean it appears from an overview of the common charges formed from ionizing various elements that each element forms one or more of either positive or negative ions, but they never have the opposite…
HyperLuminal
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19
votes
5 answers
Which substance has the highest temperature range between melting and boiling point
Which substances exist that are normally liquid and that will not freeze nor boil even at relatively low/high temperatures as compared to the freezing and boiling points of water? Or how can I identify such substances online?
If it is relatively…
Mr. Developerdude
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19
votes
3 answers
Why there is no change in water level when salt is added?
Let us say we have one glass of water and after that when we add one or two spoon of salt then we notice that salt dissolves in it but when we measure the water level we found that there is no difference between initial reading and final reading. So…
Shashank
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19
votes
2 answers
Is the relative natural abundance of isotopes of an element the same everywhere?
Wherever you find potassium, the isotopes are present in a set percentage that exists the same everywhere in nature, but why is that? Does it have something to do with how the element is produced?
HyperLuminal
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19
votes
1 answer
Why is europium used in Euro bank notes?
Europium is apparently used as an anti-counterfeiting measure in Euro bank notes because of its fluorescence under UV light.
Is there any reason why it is specifically $\ce{Eu}$ and not any of the other lanthanides that fluoresce as well?
Is it…
Gimelist
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