All Questions
Tagged with quantum-chemistry thermodynamics
29
questions
1
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367
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Why does graphite have a higher standard molar entropy than diamond?
It is known that graphite (5.7 J/K mol) has a higher standard molar entropy than diamond (2.4 J/K mol) (data from Physical Chemistry by Atkins). I understand that this must be due to the structural ...
- 11
1
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0
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49
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Critical point from ab initio calculations
I was wondering if it is possible to calculate the critical point (e.g., temperature, pressure, and density) other than via experiments or equations of state like ab initio calculations.
Would anyone ...
- 311
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0
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618
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How do longer chains and more cis-double bonds affect melting point and viscosity of fatty acids?
In fatty acids, longer chains increase the melting point (and viscosity) by increasing London dispersion forces. Inversely, more double bonds decrease the melting point.
What happens when both chain ...
- 117
3
votes
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475
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Shielding vs electron-electron repulsion
Example of shielding:
(source)
The last electron in the 6s subshell of $\ce {Cs}$ is shielded from the nucleus by the inner electrons.
Example of electron-electron repulsion:
The electron affinity of ...
user119245
4
votes
2
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231
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Spontaneous reaction between chlorine and a hypothetical atom
Suppose, my hypothetical element is $\ce X$, whose first ionization energy is $\pu{200kJ/mol}$. An atom of this element will react with an atom of chlorine (assume that I've already dissociated a ...
user119245
2
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1
answer
515
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My book's claim about the shielding effect of s,p,d and f electrons
It's a relatively unknown Bangladeshi book. It's called "Chemistry-First Paper (Class XI-XII)" by Professor Haradhan Nag
According to my book, "Electrons of s and p orbitals produce ...
user119245
1
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0
answers
341
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What causes little spikes in a flame? [closed]
I have a lighter at home which everytime I use it, generates little spikes (see picture below) which eventually disappear.
The Spikes are not an effect generated by the camera. I can confirm that ...
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292
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Why does the Most Stable State of an Atom Tend to be One with Full s and p Subshells?
I'm new to posting on stack exchange, although I've read a lot of it before. This question seems like it might end up being marked as a duplicate, but I've looked through a lot of the similar ...
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1
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161
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What is the reason that ice melts with increasing pressure at constant temperature (revelation)?
I've seen many explanations regarding this topic where they explain it in the sense of the anomalous expansion of water, but I actually want an answer where I can understand the different forces at ...
- 11
4
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176
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Has a concept of temperature ever been defined in the context of a single atom?
I wonder if this answer to What would happen if we supercool and then superheat an atom very abruptly? goes far enough.
I almost wrote the comment:
I don't think we can even talk about the ...
- 5,900
1
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What all information can be gathered qualitatively from the radial distribution functions of a molecule?
Apart from knowing the radius of coordination shells and the probability of finding, is there any other thermodynamic information we can gather by looking at radial distribution functions of a ...
- 79
2
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1
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How are octet-rule models supported by thermodynamics and quantum theory? [closed]
I understand that the four quantum numbers dictate how many electrons can "fit in a shell," but I don't understand how gaining a full octet is particularly energetically favorable.
The example of ...
- 29
0
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1
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79
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Getting the pressure of a system by series expansion
An average number, $N$, of bosons of spin $S = 0$ is conned to a two-dimensional domain
with surface $A$. The gas is ultrarelativistic with a single particle energy $\epsilon = cp$, where $c$ is the ...
- 351
6
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2
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327
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Tunneling in chemical reactions
We know that quantum tunneling is the reason behind several natural phenomenon like alpha decay and thermonuclear fusion inside the stars. How can it influence chemical reactions by tunnelling a ...
7
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2
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527
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Derivation of the Temperature Dependence of the Boltzmann Distribution
In lecture notes, Atkin's Physical Chemistry, etc. the Boltzmann Distribution is derived by first claiming that the system takes on properties of its weightiest configuration. The weight is therefore ...
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