All Questions
45,432
questions
20
votes
1
answer
940
views
When simulating spectral line broadening, which convolution is preferred?
Many computational chemistry packages permit the calculation of vibrational and electronic spectra. These spectra are obtained as a set of discrete eigenvalues however they are often convolved with ...
- 10.9k
4
votes
1
answer
12k
views
Can dissolution reactions be endothermic?
Is it possible for a dissolution reaction of the form
$$\ce{X(s) ->[solvent] X (solv)}$$
or
$$\ce{M_mX_x (s) ->[solvent] m M^x+ (solv) + x X^m- (solv)}$$
to be endothermic, i.e. $\Delta_\...
- 1,011
16
votes
1
answer
25k
views
Resolution in Mass Spectrometry
I have been reading about resolution in mass spectrometry and there are a few things I do not understand.
The resolving power is determined by $m/(m_2-m_1)$ at full width half height of a peak. The ...
- 263
5
votes
1
answer
524
views
Mercury, amalgams and mercury compounds [closed]
Mercury is toxic. It forms amalgams and inorganic mercury compounds/salts are available.
My question is on toxicity. I am interested in its toxicity, not the mode of action (as it will be part of ...
- 355
16
votes
1
answer
2k
views
What do typical results from inductively coupled plasma mass spectrometry (ICP-MS) look like, and how do I interpret them?
I have a degree in chemical engineering and remember having seen a inductively coupled plasma mass spectrometer (ICP-MS) during the laboratory part of a chemistry course I took while at university, ...
anon
7
votes
4
answers
24k
views
What is the difference between melting and dissolving?
What is the difference between melting and dissolving? I am looking some general features.
The answer should be adaptable to the melting/dissolving of ice cube (water) in a class of pure alcohol (...
- 1,011
12
votes
1
answer
3k
views
How are turbostratic graphite phases formed?
Turbostratic graphite is graphite in which there is quenched rotational disalignment between adjacent graphene sheets, i.e. one sheet is rotated with respect to its neighbor. I suppose this could be ...
- 10.9k
11
votes
3
answers
1k
views
Should one pronounce “periodic” the same in “periodic acid” and “periodic table”?
In “periodic table”, the adjective is related to the noun period, and comes from Ancient Greek περίοδος through French périodique. In “periodic acid”, it is formed from the prefix per- and iodic (like ...
- 23.8k
19
votes
1
answer
822
views
Why does benzene bend in this reaction?
From here
I can see why hapticity changes here, but not why it is necessary for the benzene ring to bend. The resonance energy of benzene is pretty large, and there's no balancing increase in ...
- 15.2k
13
votes
1
answer
2k
views
Why is the benzyne triple bond distorted?
In many places I've seen the "extra" bond in benzyne being labelled as $\ce{sp^2-sp^2}$ overlap or distorted (not parallel) $\ce{p\pi-p\pi}$ overlap. But I've failed to see why we can't have a normal, ...
- 15.2k
36
votes
3
answers
3k
views
Pauli exclusion principle and resonance
I've always been a bit uncomfortable with the concept of more than two electrons in a single orbital-like region(probability-wise) which occurs in resonance.
This seems to disobey Pauli's exclusion ...
- 15.2k
19
votes
1
answer
2k
views
What dictates the lifetime of a solvated electron in a given solvent?
Solvated electrons have a long lifetime in ammonia solutions, but their counterparts in water (called hydrated electrons) have a much smaller lifetime, of the order of microseconds in very pure water.
...
- 23.8k
9
votes
1
answer
124
views
Where do I find datasheets of zeolites?
I'm looking into uses of zeolites as water absorbers for heat storage and absorbtion cooling. However, I don't find hard numbers on the likes of absorption enthalpies at different temperatures, ...
- 780
8
votes
2
answers
1k
views
Z-matrix of a series of 5 colinear atoms
How can I write a Z-matrix for the following complex?
O==C==O H--O
\
H
I have managed to write:
...
- 23.8k
16
votes
2
answers
267
views
Is there a theory behind selecting elements that may be successful in potential superconductors?
Looking at something like $\ce{YBa2Cu3O7}$ which was one of the first cuprate superconductors to be discovered, I'm always curious how the selection of these substances as likely superconductors comes ...
- 3,007