system
Given the following post, respond as if you're commenting on Reddit:
human
Whats the difference between liquid and gas?

I know this many sound like an extremely simple question, but on a molecular level, what's the difference between a liquid and a gas?
From a young age we're shown a collection of diagrams showing how the structure of molecules in solids, liquids and gases differ. In diagram of the solid, they're touching, in the liquid, they're spaced apart and less structured, and in the gas, they're even further apart.
My assumption has always been (feel free to correct me if I'm wrong), that difference between a solid and a liquid is the molecules 'touching', there molecular bonds. When a substance becomes hot enough that's its molecules have enough energy to break there bonds, it becomes a liquid. We have a definite point in which a solid becomes a liquid.
Equally, there is a definite point when a gas becomes a plasma, when the molecules gain enough energy that there atomic bonds begin breaking down, making a soup of protons electrons and the works.
...but what's the definite point between liquid and gas?
Are there any properties that a gas has the a liquid does not? Theoretically, if we had a liquid and a gas of the same density, how would they behave differently?
Maybe a slept though a key part of my year 6 science classes and missed something. Help me atone for my younger laziness reddit!
gpt
The molecules/atoms in solids aren't really "touching," they are just held tightly together by weak intermolecular forces. There is an energy level at which the molecules/atoms are able to slide past one another despite the intermolecular forces, but are still held together: thus the liquid state. In a gas, however, each molecule/atom has sufficient energy to move entirely independently of it neighbors, which is why a gas will expand to fill it's container etc.