Molecules in a solid vibrate slightly as the
intermolecular attractive forces are stronger than the heat
energies of the molecules. The strong intermolecular forces attract
and bind the molecules together in a rigid structure. Hence, a
solid has a definite shape and volume. You need to apply force to
change its shape.
Matter consists of tiny molecules that are combined
in a variety of ways. Intermolecular forces attract and bind these
molecules together. However, disruptive heat energies cause the
molecules to be in constant motion.
Compared to a solid, the molecules in a liquid are
not very close to each other and have a greater freedom of
movement. Because the molecules are free to move with respect to
each other, a liquid does not resist forces to change its shape.
However, a liquid has sufficient molecular attraction to resist
forces to change its volume.
As heat is applied to a liquid, its molecules
vibrate faster and some molecules gain sufficient heat energy to
overcome the intermolecular attraction at the surface of the
liquid. These high-energy molecules break free from the liquid and
are now in the gaseous state.
In a gas, molecules are widely dispersed so the
intermolecular forces are almost non-existent. Its molecules spread
out freely to fill all the space available. A gas offers no
resistance to change of shape and little resistance to change of
volume.
Structure, movement & properties - NGfL
|
States of Matter - Harcourt
|
Changing Matter