so in a zero pressure environment like space, does that mean all matter is out of phase until gravity or some form of surface tension groups atoms together?

Just think of nuclide as describing a random atom the has Z protons and N neutrons whereas isotopes is refering to a specific element (Z) with varying number of neutrons N.

How is thermodynamic temperature different from viewing it from a kinetic perspective?

Does that mean that the movement of atoms relative to each other, in the kinetic sense of temperature, is not what the temperatures talk about in thermodynamics? So temperature is not a universal concept then? It is context dependent, and has many definitions?

No worries. I actually appreciate the correction! Ironically I was enervated when I wrote this so I mistyped the word lol

[removed]

And to add the comment about how velocity is relative, even if you have a large mass of material moving quickly, this doesn't make it hotter. So, velocity isn't by itself the metric you need but variance in velocity, where velocity is a vector quantity. This way you can get a picture of the range of differences in velocity amongst the particles. Temperature is directly related to this (and would only be related to this for simple point masses that only react like billiard balls.)

[removed]

Nah, for covalent the state is going to be determined by the strength of Van der Waals forces. For ionic compounds the mp and bp will relate to the electronegativity...distance and shielding making it weaker. For metals it must be the charge of the cation. Technically, if you had one atom, it has none of these intermolecular, covalent or ionic forces at play, so you could call it a gas, at an incredibly low concentration.

Ah yes, this helps a lot. Brings back a lot of statphys memories too. Thank you very much.

In a way, a time averaged system could be described as a mixed-state density matrix I suppose, which is where my intuition comes back again. I always picture a single object as being in a pure state, but there are ways it doesn't have to be.

Because when you say that entropy is tied to the probability of an observation, that really doesn't hold for an object in a superposition, since its multiplicity of states is just 1 (the superposition itself), which is where we do need to be careful I guess. I'd call it classical probabilistic, and avoid all confusion with quantum probabilistic.

So, to get more philosophical: It feels like there needs to be some sort of "outside influence" on a single particle for it to have entropy. Would you agree with this line of thinking? For some definition of outside influence.

That is not me trying to say my intuition was right by the way, it wasn't.

[removed]

Sure. That is the electronic temperature. I was coming from the perspective of a classical point-particle picture and the kinetic, not thermodynamic, definition of temperature.

[removed]

What if it was a single atom frozen in other types of matter? Couldn't you say it was frozen/moving slow in relation to the matter around it regardless of type?

[removed]

Not to be super pedantic, but the word you want is “innervated.” “Enervated” means tired. Which it’s certainly possible the arms are as well, but I don’t think it’s what you meant.

[removed]

I think this is both true and kind of not and it gets weirdly philosophical. It doesn't have temperature as we're taught about it in HS physics class, sure, since that is generally the internal kinetic energy of molecules vibrating and bumping into each other, but atoms themselves have internal degrees of freedom at the quantum level that can reasonably be used to describe temperature. The excitement state of an atom's electrons is the most obvious one.

No, because of zero-point energy atoms even at absolute zero still have some kinetic energy and thus a temperature.

[removed]

That would define the electronic temperature, not the temperature of the atom in the classical, point particle picture.

[removed]

Keep in mind that we cannot ethically study whether or not the virus has become less deadly. For the last 10-15+ years, "test and treat" has been the law of the land (it's taken longer to get set up and running in many parts of the world, but now test and treat is everywhere). "Test and Treat" means that as soon as you are shown to be living with HIV, you are immediately counseled and referred for antiretroviral therapy, which has dramatically improved survival rates in nearly everyone. HIV is a manageable infection now, and post-infection life expectancies are now similar to pre-infection life expectancies.

So you're very much comparing apples (HIV and AIDS in the 80s, 90s, and 00s, depending on where you lived) to oranges (HIV and AIDS now).

Source: infectious disease epidemiologist working on HIV/AIDS for 25+ years

Yes, but even that is still one to one correspondence with the partition function which is the number of accessible states.

The thermodynamic entropy is actually defined well at the atomic level. Where as many other properties only exist in the bulk limit.

When we talk about delocalized electrons in metals, that really applies when they're metallically bonded - ergo, when there's multiple. So yes, it does apply to metals!

A grain of sand is just that, a grain of sand. Two gains of sand are two grains of sand.

If you add more and more sand, at some point you can say you have a pile of sand, and you can describe it with new properties.

Atoms are basically the same, you need a bunch of them and then you can describe them with new properties such as viscosity, state of matter and so on.