“Spontaneous” is actually the correct word to use here, using its definition in statistical mechanics.

Here’s an example: https://principlesofchemistryopencourse.pressbooks.tru.ca/chapter/5-6/

This post isn't showcasing mansplaining. It's showcasing pedantry.

Just like this comment!

Spontaneous doesn't mean "happens suddenly without explanation" what are you on about?

Everything has a cause.

Wrong, wrong, wrong.

Eh, it definitely has a cause. A known one.

Nothing to do with the physical definition of spontaneity. Spontaneity of a process just means that the ∆G is negative or total energy of the system is lower after the process, and additional energy isn't required for the process to be thermodynamically allowed. This is, and I can't stress this enough, the simplest of simple thermo.

for the sole reason which specific molecules is nigh impossible to predict

Also unrelated, but it is fully impossible to predict, since in trying to predict it well enough you reach quantum scales where everything is probabilistic. That doesn't at all mean everything is spontaneous.

So, who is correct depends entirely on the mental framing of what someone thinks of when they read "water".

Nope, the first person is strictly correct and the second is strictly incorrect, as described above.

Water as an abstract idea of a specific type of fluid? Not spontaneous.

Nope, exactly spontaneous. You could even forget about water entirely and model this just as a bunch of nuclei and electrons in a box and derive that the lowest energy state has them being in a gas of atoms, and the initial state doesn't, which is enough to demonstrate by our earlier statements that boiling is spontaneous.

Water as in what will literally happen to the bottle of water in the picture?

This is "not even wrong" territory.

This post isn't showcasing mansplaining.

It absolutely is. We will define mansplaining here as the confidently incorrect dismissal of statements of women by men where we suspect that the genders of the participants may play a role.

The first part has been demonstrated above. It is also reasonable to assume the second given that we observe this happening to women at a far greater frequency than to men. Although, like with atoms, we cannot prove that this individual instance is a direct result, it is consistent with the probabilistic data and we would need additional evidence to conclude that this particular guy just goes around wrongly correcting everyone equally.

Nearly valid pedantry at that.

Once again, not remotely.

While you are technically correct, you also misunderstand who the target audience is and what language is required to actually make people understand.

When speaking to a normal person you don’t want to slap random jargon and care too much about precise definitions. So in that context spontaneous is a great word to describe what is happening. People without deep backgrounds in the field will not understand technical jargon and it will only make them not pay attention.

I'd still say it's spontaneous because when you reduce pressure you're removing a factor rather than adding one. It's like saying "when you compress a spring and then remove the compression force, it will spontaneously return to its previous length." Water vapor can be seen as water's "natural" state when thero no pressure forcing it to be a liquid. Also saying "simple thermo" to an astronaut is definitely mansplaining, because it implies the other person doesn't know that simple thermo. Maybe it's just pedantry, but in that case damn that's some terrible phrasing.

Hahaha, under that definition nothing spontaneous can ever occur

no

It's not an external cause. It boils on its own, because the molecules don't want to be close together.

You should be an astronaut

I agree, it really is showcasing pedantry. That man is just an asshole, not a misogynistic asshole. To me, this thread is full of confirmation bias. People who want to see what they personally believe, not objective reality.