1: THE LIQUID STATE OF MATTER
Liquid water is common, but because liquids can exist only within a relatively
narrow range of temperatures and pressures,
... [Show More] the liquid state is the least
common state of matter in the universe. For example, of the 92 naturally
occurring elements, 79 are solids, 11 are gases, and only two (bromine and
mercury) are liquids.
Earlier we used the kinetic molecular theory to explain the properties of
gases. This same theory is used to explain the properties of liquids. Liquids
have less kinetic energy than gases, so the intermolecular attractive forces
are strong enough to hold the liquid particles close together but not strong
enough to keep neighboring particles in a fixed position, meaning the
particles are free to move past or slide over one another.
SOLID LIQUID
GAS
A liquid has a definite volume but not a definite shape because the
intermolecular attractive forces are strong enough to hold the particles close
together. Like a gas, a liquid takes the shape of its container (but just the
lower part of the container, whereas a gas fills the entire container).
Liquids and gases are both fluids because the particles that make up the
liquid are moving (vibrating and rotating) enough to prevent the substance
from having a fixed shape. This means that both gases and liquids flow.
Unlike gases, particles in both liquids and solids have stronger attractive
forces between them, which results in the particles being packed together
much more closely, meaning liquids have higher
densities (mass/volume), about 1000 times those of gases.
Because the particles in a liquid are close together, a liquid is relatively
incompressible, whereas gas volumes can be radically compressed so that
the final volume is 1/1000th of the original volume. Since gases have much
empty space separating the particles from one another, the particles can be
pushed together to fill that empty space, compressing the volume of the gas.
Liquids have the ability to dissolve other substance, serving as a
solvent to dissolve the solute (the solid or liquid substance that dissolves).
This ability is somewhat limited by the "like dissolves like" rule, which says
polar liquids only dissolve polar (and ionic) substances and nonpolar liquids
only dissolve nonpolar substances. Oil (nonpolar) does not dissolve in water,
which is polar, but sugar (polar) dissolves in water. Oil (nonpolar) does
dissolve in gasoline [Show Less]