Disorder
Disorder
is the natural state of things, just think about your bedroom! Without careful
attention a bedroom soon becomes cluttered with things all over the place.
The reason for this is fairly logical; there is only one situation in which
everything is ordered in a bedroom, all of the socks in the correct drawer,
the bed made, the books on the shelves, tee-shirts folded etc etc. However,
there are millions of ways in which the room can be untidy.
If
nature is left to itself, the most likely situation is one of disorder - the
probability of disorder is much greater.
Natural systems do not usually have someone to arrange them, they adopt the
most likely arrangement.
Within a natural system there are billions upon billions of particles, each
of which can be given a wide range of energies. The system adopts one of the
most likely states, i.e. a disordered state.
top
Entropy
Entropy is the term given to the natural disorder of the universe. If left
to itself, the universe tends towards disorder. It can be thought of as
an inevitable driving force. Entropy has been called 'nature's arrow'. It
is the natural tendency of systems to become disordered.
If
we look at a solid, we can see that all of the particles are carefully arranged
in specific locations. This is a highly organised and ordered system. Its
entropy is said to be very low.
However, in a gas the particles are free to move randomly and with a range
of speeds. The entropy of gases is high.
A liquid has more entropy than a crystalline solid, but much less than a
gas.
A solution contains a mixture of solute and solvent particles and has more
entropy than a simple liquid but, once again, far less than a gas.
State
|
Entropy
|
solid
|
very low
|
liquid
|
low
|
gas
|
high
|
top
Factors affecting entropy