When we speak of physical chemistry, a liquid is a substance that fills the container in which it is located. It does not have a regular structure, but the molecules that make up the liquid move randomly. The hotter, the faster they move. The vapor pressure increases above the open container until it is equal to one atmosphere, and then begins to boil. When the temperature is lower than the boiling point, you see a certain surface held there by surface tension. When it cools, the molecules move less quickly and begin to crystallize in the solid.
It all depends on intermolecular forces that are electrostatic and long. They are usually called van der Waals forces in the liquid phase. Sometimes molecules have dipole moments, and sometimes not. The former are called polar liquids, and the latter are non-polar.
Life depends on the availability of liquid water. We believe that any other life in the Universe should have an environment with liquid water.
Here I am talking about ordinary liquids such as ammonia, water, benzene, etc., and these liquids have a certain temperature at which they freeze and boil. As for water 0 C and 100 C. But if you look out the window, you look through the glass.
The glass is a supercooled liquid. (it gets cooler!).
This means that when you heat the glass, it does not suddenly melt, but begins to become soft, and then softer, without a sharp melting point. These solids do not have a crystalline structure. They have a random orientation of the molecules (usually silica) and are called amorphous (not love).
A liquid crystal display (LCD) is also a liquid.
But there are other types of liquids, such as liquid crystals. You have a clock on the clock and on TV screens: a liquid crystal display (LCD). They flow like liquids, but all molecules can be directed equally. They are between the liquid and the crystal. Since they have a crystalline structure, it is possible to apply heat or charge in a small area, and this changes the orientation (phase) in this place. Since the light is scattered differently from other regions, it looks different - it displays an image caused by the shape of the area, heat or charge applied.
Then there is Mercury, fast silver and liquid. This is a heavy metal poison, so do not touch it. All metals melt ever, just Hg has a melting point much lower than other metals.
Cold liquids for cold shows and events.
How about really cold liquids? In concerts and theaters, you often see white fog. It is liquid nitrogen, harmless when it evaporates, because air is 80% N2. It's pretty cold, minus 196 ° C, so when it evaporates in the air, it cools the air, so you see that you see water crystals freeze in the air.
The lowest liquid boiling point is liquid helium. Think about it. This is a small spherical atom (filled 1s2 orbitals), therefore there are very small forces between them. They just roll each other. It has a boiling point of 4.22 degrees above absolute zero. Thus, it boils at 4.22 K = -268 ° C.
You've heard of superconductivity: - solids that have zero electrical resistance.
it's the same superfluid They have no viscosity, but have a surface tension like a liquid. They flow right along the sides of the container. Liquid helium is an example of a superfluid liquid.
I hope this will give a little review of the physics and physical chemistry of liquids.
